M

OTS80PB and OTS60PB

OTS100AF, OTS80AF and OTS60AF

Oil Test Set

USER GUIDE

1
 G SAFETY WARNINGS

Safety warnings and precautions must be read and understood before the OTS is used. They must be observed during
use.

„„The OTS must be used only in the way intended and for the stated purposes described by Megger.

„„The OTS must not be used if any part of it is damaged.

„„The OTS must be properly earthed. A supplementary earth terminal is provided.

„„Position the OTS so that power can be easily removed.

„„The OTS must not be used in wet locations or with rain falling on the instrument.

„„The OTS must be used only for testing electrical grades of insulating liquids. No other objects or substances
should be placed in the test chamber.

„„The OTS must be used only with one of Megger’s precision test vessels or VCM100D/VCM80D correctly fitted on
the support horns in the test chamber.

„„Replacement fuses must be of the correct type and rating.

„„If batteries are fitted, the 12 VDC charger must only be powered from a negative earthed vehicle 12 VDC source
using the Megger supplied lead. - PB units only

„„Calibration or repair must be carried out only by a Megger qualified repair facility.

„„The test chamber must be kept clean and free from lint or other fibres.

„„The OTS80PB/OTS60PB weighs between 16 kg and 23 kg.

The OTS100AF/OTS80AF/OTS60AF weighs 30 kg.
Care should be taken when lifting the instrument.

„„It is prohibited to insert foreign objects into any gap on the instrument before or during a test.

„„Unit must be used in a well ventilated location. Small quantities of ozone may be created after prolonged
testing.

NOTE
THE OTS MUST BE USED BY ONLY SUITABLY TRAINED AND COMPETENT PERSONS.
IF THESE INSTRUMENTS ARE NOT USED IN THE MANNER SPECIFIED PROTECTION
MAY BE IMPAIRED

2
Symbols used on this instrument

G Caution: refer to accompanying notes

F Danger high voltage, risk of electrical shock

d DC voltage

a AC voltage

c Equipment complies with current EU Directives

u Earth terminal

f Fuse

USB terminal

Equipment complies with ‘C tick’ requirements

Do not dispose of in the waste stream

3
Contents
Accessories and equipment 24
Safety warnings 2
Optional 24
Symbols used on this instrument 3 Spares 24

General description 5 Repair and warranty 25

Features and benefits 6 End of life disposal 26

Applications 7
Instrument controls and indicators 8
Keypad and printer panel 8
Rear panel 9
Preparations for use 10
Getting started 10
Supply voltage 10
Assembly 10
Test vessel preparation 10
Instrument setup procedure 12
Calibration 13
Test vessel mortised stirrer 13
Transportation and storage 13
Operating instructions 14
Top level tabs 14
Navigation and character entry 15
Set favourite test standards 16
Performing a breakdown test 16
Test in progress 16
Test results 17
Custom tests 18
Basic memory functions 19
Transfer results to USB flash drive 19
Print quality and changing paper 20
Vessel and electrodes 20
VCM100D/VCM80D 20
Test vessel motorised stirrer 20
Preventive maintenance 21
General 21
Cleaning 21
Care for OTS electrodes 21
New electrodes 21
Electrode storage 21
Cleaning oxidising/dirty electrodes 21
Technical specifications 22
Technical specification 22
VCM100D/VCM80D voltage meters
technical specification 23
Storage and transportation 23

4
General description
Megger’s Oil Test Sets are liquid dielectric breakdown
testers.

The OTS80PB, OTS60PB models are portable

instruments, designed for use in the field, where as the
OTS100AF, OTS80AF and OTS60AF are designed for
laboratory use.

They are fully automatic, powered by battery or mains

(model dependent) and facilitate accurate breakdown
voltage tests on mineral, ester and silicon insulating oils.
The precision test vessel sets the accuracy standard for
the liquid insulation test industry. For ease of use the
instrument comes pre-programmed with a ‘library’ of
international breakdown test standards and the ability
to create custom tests.

The instrument is housed in a metal case with moulded

end caps that accommodate convenient carry handles. The test chamber is designed with an easy-clean surface and
provides a drain for spilt oil through an internal pipe routed to the rear of the instrument. A beaker or similar can be
used for spillage collection. The test area is covered by a plastic lid with an electrically protective inner conductive layer
which, with the metal case, provides a safe equipotential enclosure for high voltage testing.

The lid allows in plenty of ambient light and users are able to view the test and witness stirring and the breakdown. The
chamber lid is dual redundant safety protected with micro-switches to prevent accidental electrification.

The advanced test vessel design yields highly accurate and repeatable results. Two stirring options are available; an
internal magnetic bean stirrer which is dropped into the oil and an optional lid mounted impeller that conforms to the
ASTM D 1816 standard. Stirring during breakdown testing is employed to produce an homogeneous distribution of
contaminants within the oil and to free any carbon generated between electrodes during testing.

Electrode gap is set by precision adjustment wheels that lock in position ensuring that the electrodes do not move
during a busy day in the field. It is, however, advisable to check the electrode condition and gap daily because it is a
critical parameter in breakdown voltage testing. Flat anodised Aluminium gap setting gauges are supplied in popular
sizes to facilitate electrode gap setting. Electrodes are detachable and are available in shapes that meet all international
standards, i.e. disk, spherical and mushroom (VDE) electrodes.

A selection of international breakdown tests are chosen from a library of standard sequences and started from the user
friendly menu on the LCD display. The top level test screen displays all pertinent test information to ensure the correct
electrodes are used with the specified electrode gap setting.

Results are viewed on screen and printed on either an external USB printer or the internal printer following a test result.
In the event of a breakdown not occurring before reaching the maximum voltage, the instrument will return maximum
voltage. This is a safety measure to ensure the instrument is not driven over its designed maximum voltage.

The instrument automatically turns off the display 15 minutes after completion of a test sequence or last use.

Safety features incorporated in the design include dual safety micro-switches and zero volt touch bar, the screened
chamber lid and convenient power supply On/Off switch. Pressing any button during a test will immediately remove the
high voltage and terminate the test. It is important to earth this instrument using the ground connection at the rear of
the instrument to ensure safe operation.

OTS PB models
The OTS60PB (60 kV) and OTS80PB (80 kV) oil test sets are small and the lightest on the market with weight ranging
from 16 kg to 23.5 kg depending on model configuration. They come complete with optional carry bag and transport
case. The carry bag has pouches for electrode accessory pack, leads, quick user guide, paper roll etc. These units can be
supplied mains powered only, or mains powered and battery operated for additional flexibility in portable applications.
The optional batteries are NiMH, or if selecting an 80 kV model a lead acid battery can be specified. In addition, an
internal 12 V DC charger and vehicle adaptor cable is standard when any battery option is fitted.
5
The OTS80PB is line powered with the option of internal batteries (either Lead Acid, NiMH or no battery) but the
OTS60PB only offers NiMH battery or no battery option. In addition to line power charging, a 12 V DC charger facility
is factory fitted with either battery option. A vehicle 12 V DC charger cable is provided to charge the instrument’s
batteries. Customers who order one of the battery pack options should be mindful of the need to maintain battery
capacity. As a minimum, lead acid batteries should be fully charged every 3 months. Customers who chose the NiMH
battery option are advised to operate from battery without line power periodically to ensure maximum battery life.

OTS AF models
The OTS60AF (60 kV), OTS80AF (80 kV) and OTS100AF (100 kV) models have much a larger test chamber for even
easier access and cleaning, particularly useful in a lab environment. They are fitted with a 12 key alpha-numeric keypad
to facilitate entry of test ID, file names, notes etc. Alpha characters are entered by repetitive pressing on a key, the same
way as text is entered in modern cellular telephones. The AF models also have the ability to use a USB barcode reader
to scan oil sample barcode labels, ideal for better integration with a LIM system.

Features and benefits

„„Fully automatic breakdown tester with test voltages up to 100 kV / 80 kV / 60 kV depending on model
„„Advanced 400 ml oil vessel with accurate electrode gap setting and adjustment locking mechanism
„„Flat electrode gap gauges that will not damage electrodes
„„Easy clean test chamber with oil drain
„„Magnetic bead stirrer or optional lid mounted impeller (conforming to ASTM D 1816)
„„Direct trip control employing voltage and current measurement
„„Rapid response to trip (<10 μs)
„„Automatic oil temperature measurement
„„Intuitive user interface with backlit QVGA colour display (visible outdoors)
„„Simple transfer of test results via USB flash drive
„„USB barcode reader scans oil sample barcode labels (AF models only)
„„Optional VCM100D/VCM80D voltage check units measure voltage directly
„„Optional carry case with shoulder strap (PB models only)
„„Optional transport case (PB models only)

6
Applications
The oil test set is used for determining the dielectric strength of high voltage insulating liquids, such as the insulating
oils used in transformers, switchgear and other electrical apparatus. The dielectric breakdown voltage is a measure
of the insulating ability of a liquid to withstand electrical stress. Contaminants such as cellulosic fibres, conducting
particles, dirt, and water reduce breakdown voltage of an insulating liquid. A low result indicates the presence of one
or more of these contaminants.

The test set is fully automatic. The operator has simply to prepare the test vessel, load it with sample oil, place it
in the test chamber, select the appropriate specification for the tests and then start the test sequence. The test set
automatically carries out the sequence of tests as defined by the pre-selected national specifications. Oil testing
specifications, for which the sets are pre-programmed, are as follows:

„„ASTM D 1816-12 „„BS EN 60156-96 „„SABS EN60156

„„ASTM D 1816-12E (ester oil) „„CEI EN 60156-95 „„VDE0370 part 5
„„ASTM D 877A-13 „„IRAM 2341 „„AS1767.2.1
„„ASTM D 877B-13 „„UNE EN 60156 „„PA SEV EN60156
„„IEC 60156-95 „„NF EN 60156 „„IS C 2101-99 (M)
„„BS148/EN60156 „„GOST 6581-75 „„JIS C 2101-99 (S)
„„IS 6792 „„IS 6792-2

A critical factor with respect to field testing of oil is its temperature, because samples from a transformer taken shortly
after switch off can be many degrees hotter than equivalent room temperature laboratory tests performed at 20 ºC to
23 ºC.

NB: Certain standards require field tests to be performed between 20 ºC and 30 ºC.

7
Instrument controls and indicators
Keypad and internal printer panel
The control panel, illustrated below, is located to the front right side of the instrument and contains a QVGA colour
screen (1), navigation keypad with ‘OK’ button and a ‘TEST’ button. The operation is user friendly and driven from six
top level windows. A start-up LED is used during instrument initialisation. The lower, vertical section of the front panel
houses an ON/OFF power switch and a USB Type A interface socket

OTS PB models item description

1. 3.5 inch, backlight, bright colour QVGA display

2. On/off LED
3. External power LED / icon
4. TEST’ button with associated red warning LED
5. USB socket
6. Navigation keypad with ‘OK’ select button
7. ON/OFF

OTS AF models item description

1 1. 3.5 inch, backlight, bright colour QVGA display

2. On/off LED
3. External power LED / icon
4. TEST’ button with associated red warning LED
2
5. 12 key alphanumeric keypad
6. Navigation keypad with ‘OK’ select button
3

5
6

The instrument printer panel, shown below, houses the optional internal printer. A flat
panel replaces the printer if not ordered. The printer is a dot matrix impact printer with
57.5 mm wide paper roll. Paper results printed on this printer will not blacken in high
temperatures. The panel has two locking studs and a control print advance button.

8
Rear panel
The rear panel illustrated below accommodates all connections to the instrument with the exception of a front facing
USB interface.

OTS PB model item description

1. Ground connection with cable lug

2. IEC line power socket

3. Fuses

4. USB Type A socket

5. USB Type B socket

6. 12 VDC charger socket

OTS AF model Item description

1 2
1. Ground connection with cable lug
2. IEC line power socket
3. Fuses
4. USB Type A socket
5. USB Type B socket

3 4 5

It is mandatory for safe operation that an earth ground cable is attached to this instrument before performing tests.
The ground connection is identified as item 1 in the illustration. Attention must be paid to product warnings and
markings.

Line power is applied via an IEC socket (2) and is fused (3). On all PB models, the internal batteries, if supplied, can be
charged by a jack type socket (6) from a vehicle or correctly rated wall plug transformer. If batteries are ordered with
this product a charger and vehicle charging cable is supplied. Note that the instrument is not designed to operate from
12 VDC, only to charge the batteries.

Two USB interface connectors, one type A (4) and one type B (5), offer USB host and device interfaces. A second USB
type A (host) interface is located on the front of the instrument for user convenience. The USB type A interface (4) is
used to drive a printer or flash/hard disk drive.

9
Preparations for use

Getting started
It is important to read the user guide thoroughly before operating the Oil Test Sets for the first time. The safety
warnings are particularly important.

Supply voltage
Before connecting line power to the instrument, the ground connector should be connected to a suitable earth point.

Both the AF and PB models are designed to operate on 50/60 Hz AC line power in the range 90 to 265 V AC.
For PB models, a 12 V DC power circuit for battery charging is fitted when either NiMH or lead acid battery packs are
ordered. The battery can be either charged using the supply 12 V vehicle charger cable or from mains power.

Assembly
„„Unpack instrument and contents of the packing box.
„„Ensure that the instrument is placed on a solid surface or table with sufficient working space.
„„Connect ground to a suitable earth connector.
„„Fitselected electrodes to the threaded shafts in the test vessel taking care not to scratch electrode surfaces.
Electrodes should be hand tightened onto the shafts to prevent any movement during use.
„„Adjustment of the electrode gap should be done with the feeler gauges provided, adjustment wheels locked and
the gap rechecked.
„„Fit test vessel into instrument chamber.
„„Ifbatteries are fitted, before switching on the instrument for the first time, connect power and leave for a period
of at least four hours. This will ensure a full charge of the battery. (PB models only)
„„Read the section in this document entitled, “Instrument Operation” before powering up the Oil Test Sets for the
first time.
„„Connect line power.
„„Turn on the instrument.
„„Follow the instrument setup procedure detailed below.

Test Vessel Preparation

1. Storing and subsequent cleaning

IEC 60156 recommends that a separate test vessel assembly is used for each type of
insulating fluid that it is to be tested. The standard requires that the test vessels are
filled with dry insulating fluid of the appropriate type, then covered and stored in a dry
place.
ASTM offers an alternative option of storing the vessels empty in dust-free cabinet.
Immediately prior to testing, vessels stored full of oil must be drained and all internal
surfaces, including the electrodes, rinsed with fluid taken from the sample to be tested.
The vessel should then be drained again, and carefully filled with the test sample,
taking particular care to avoid the formation of bubbles. If the vessel was stored empty, or if it is to be used for a
different type of fluid from that with which it was filled during storage, it should be cleaned with an appropriate
solvent before rinsing and filling.
ASTM D1816 specifies the use of a dry hydrocarbon solvent such as kerosene, which meets the requirements of D235.

Solvents with a low boiling point should not be used as these evaporate rapidly, cooling the vessel and giving rise to the
risk of condensation. Solvents commonly used include acetone and, in the USA, toluene. Toluene is banned in Europe.

10
Use lint-free clean-room wipes to clean the vessel. Do not use paper towels as they may introduce particles that hold
moisture, causing breakdown values to be dramatically reduced.
Touching the electrodes or the inside of the vessel should be avoided and during cleaning, the electrodes should be
checked for pitting or scratches that may cause breakdown voltage values to be decreased. Remember that the rules of
cleaning apply to all parts that will come in contact with the oil sample during testing.

2. Setting the electrode gap

Setting the electrode gap accurately is very important; the results obtained are only valid if the
gap is correct. A big problem is movement of the electrodes after the gap has been set and for
this reason, many users of oil test sets check the electrode gap frequently – sometimes before
every test. A better solution is to use test sets where the electrodes can be locked in position,
such as the instruments in Megger’s latest OTS range.
Megger recommends the use of flat, smooth gap gauges. The latest Megger gauges have a
black anodized coating, which not only provides a smooth surface but also shows when the
gauge is worn, as the shiny aluminium starts to show through the coating.

3. Rinsing and then immediately filling the test vessel with the insulating fluid sample

Prior to filling the test vessel it is important to rinse the vessel with clean oil or with some of the sample oil about to
be tested. Rinsing should always be performed before each test, even if performing repetitive testing in an oil test
laboratory.

Remember that when rinsing the vessel, equal attention should be given to any magnetic bead, impeller, baffle plate,
lid and to the electrodes, not just the vessel walls. Rinsing should be applied to any surfaces that will come in contact
with the oil sample during testing.

After rinsing the test vessel with the sample oil it is most important to ensure it is immediately filled with the oil sample
to be tested. Any significant delay, (even a few minutes), may result in the oil film on the vessel’s walls absorbing
water from the air; since the walls have a large surface area, this is likely to contaminate the oil sample and reduce the
breakdown voltage once it has been mixed with the sample. Just 30 parts per million, (ppm), of water is sufficient to
halve the breakdown values.

In fact, ASTM D1816 specifies that the test vessel must be filled with the oil sample within just 30 seconds of the
rinsing taking place.

When filling, pour the oil sample into the vessel swiftly but with minimum turbulence so as not
to entrap air.

Allow the sample to stand for a few minutes before testing to allow air bubbles to clear.

However is important not to leave the sample to stand for longer than absolutely necessary
as it may absorb water from the air in the headspace above it, again reducing the breakdown
voltage. As soon as the bubbles have cleared the baffle/lid should then be fitted to exclude air
contact as below.

„„Excluding air from circulating oil when using an impeller to stir the insulating fluid sample

If you are using an impeller stirrer that utilises a baffle plate to exclude air from the oil sample, ensure that oil does not
pass over the upper surface of the baffle plate.

It is also important that the oil sample is in full contact with the underside of the baffle plate.

This will prevent moisture being absorbed from the contact of

circulating oil with air as intended by the test standard. 400ml Fill to Line
400ml Fill to Line

„„Fill the test vessel slowly and down the side wall as not to
cause splashing that will introduce unwanted air bubbles into
the test sample

FILL TO 400ml LINE

✓
400ml Fill to Line

✖
400ml Fill to Line

DO NOT OVERFILL

11
 „„Fill the test vessel to the 400ml fill line, DO NOT OVERFILL
„„Gently place the stirrer lid onto the test vessel so that the
baffle plate contacts the oil slowly, again so not to cause

✓ ✖
400ml Fill to Line 400ml Fill to Line

splashing that will introduce unwanted air bubbles into

the test sample
400ml Fill to Line 400ml Fill to Line

„„Periodically remove baffle plate from the stirrer lid and clean
thoroughly. FIT STIRRER LID CAREFULLY DO NOT SPLASH

Empty trapped oil - occurs if overfilled

Figure 4 Filling the test vessel

4. Selecting the optimum stirring option for the insulating oil sample to minimise air/moisture
contamination

When testing to IEC 60156:

IEC 60156 allows the optional use of a stirring impeller, the use of a magnetic bead stirrer or even no stirring at all.
The standard states that differences between tests with or without stirring have not been found to be statistically
significant. The use of a magnetic stirrer is only permitted when there is no risk of removing magnetic particles from
the oil sample under test. When oil is used as a coolant as well as an insulator it may be useful to stir the sample during
testing. For example oil from a transformer is normally circulated in use to help cool the transformer, but in doing so
might also pick up contaminants and debris with it; so to achieve the most realistic breakdown results an oil sample
taken from such a device would normally be stirred during test to ensure the best chance of detecting any detrimental
effects of particle contamination. Oil from a circuit breaker is normally static in use, so particles would naturally fall to
the bottom where they are unlikely to cause a problem. So in static use applications, an oil sample would not usually be
stirred during testing.

The use of a magnetic bead for IEC60156 is recommended where possible as oil will circulate in the lower portion
of the test vessel, whereas the impeller will circulate all of the oil in the test vessel. The magnetic bead therefore has
the advantage that any moisture absorbed by oil in contact with air is not stirred into the sample, avoiding unwanted
contamination. If the impeller is used it is vital that air is prevented from coming into contact with the surface of the
oil by fitting the baffle plate and ensuring that the oil level is sufficient to make contact with the bottom surface of the
plate without flowing over its top surface.

When testing to ASTM D1816:

ASTM D1816 specifies that the oil is stirred throughout the test sequence, and a two bladed motor-driven impeller
is specified. The standard prescribes the impellor dimensions and pitch as well as the operating speed, which must
be between 200 rpm and 300 rpm. But remember, with this stirring requirement it is vital that air is prevented from
coming into contact with the oil as described above.

When testing to ASTM D877:

ASTM D877 does not specify oil sample stirring.

12
Instrument setup procedure
The required language option is selected from the top level tabbed window. Use the right arrow key to navigate across
the tabs to the language screen. The flag symbol is used as an icon representing language option. Simply use the up/
down arrow buttons to select the required language and press ‘OK’.
The following actions, accessed from the Settings tab window, should be taken before running a test:
1. Set date and time – Time/Date option.
2. Adjust the display backlight for optimum legibility – Display Setup option.
3. Select units - metric or imperial.
4. Set printer options.
A library of international oil test standards is preloaded into the instrument. It is important to select the test standards
that will actually be used to prevent having to navigate through the complete list. Navigate across the top level tabs
using left/right arrow buttons to the ‘Tools’ window and use the up/down arrow buttons to go to ‘Select Favourite
Tests’.

Navigate to a required test and press OK to select or deselect a standard test. Functions like, ‘SELECT ALL’ and ‘RETURN’
when all required standard tests have been selected.

Calibration
The Oil Test Sets are calibrated in the factory prior to delivery so there is no need to calibrate on initial setup.

The VCM100D/VCM80D voltage check devices can be used to confirm the output voltage of the instrument by reading
the voltage directly at the electrode before running tests. Periodic checking of actual test voltage using the VCM100D/
VCM80D is recommended. The voltage check test is accessed from the Tools tab window.

Test vessel motorised stirrer

Unpack the optional motorised stirrer assembly from its box and fit the stirrer
shaft to the underside of the stirrer assembly. The unit is ready for use. The oil
test vessel lid is removed and the stirrer assembly used as a lid for tests that
require stirring.

Megger supplies as standard with the stirrer lid assembly three impellers.
Firstly there’s the large red impeller which is useful for very dirty oil. This has larger blades to help ensure the effective
circulation of any particulates between the electrodes during the test so that the full potential of their effect on
breakdown voltage may be assessed.

The other two impellers are alternative impellers. The Impeller on the left is optimised for IEC 60156, whilst the one on
the right is ideal for ASTM D1816.

Vigorous circulation can exacerbate the inclusion of any moisture captured on the surface film of oil left behind after
rinsing at the vessel preparation stage, making the need for rapid filling even more critical, so as not to detrimentally
affect breakdown results.

Refer to application note ref “OTS_VESSEL_AN_en” for further information on vessel and impeller preparation.

Transportation and storage

The Oil Test Sets are precision instruments that generate high voltage upto 100 kV (model dependent) and need to be
transported and stored carefully.

A transportation case is available as an option and required by customers wanting to transport the OTS80PB or
OTS60PB instruments by road, rail or air.

The unit should be stored in a room or area where the environment is within the temperature range of -30 ºC to 65 ºC
and maximum humidity of 95% at 45 ºC.

13
Operating instructions

Top level tabs

The user is presented with a set of six tabbed, top level windows as depicted below which facilitate instrument control.
Left and right arrow keys navigate between tabs.

Home Setup File

Information Tools Language

The home tab contains summary information for each showing the selected automatic test standard, ID of
the asset the insulating liquid comes from, the type of insulator, electrode gap and the stirrer if required.
This is the main screen from which tests are run.

Setup window offers instrument settings of language (can also be set from language window – overcomes
difficulty when instrument is set to unknown languages), time/date, display, units, printer and a setting to
select fast detection of breakdown.

Users can print, save, recall, delete and download results to a USB drive from the file window.

The Information window offers details about the instrument software configuration/version as well as a help
function that serves as an indexed user guide.

The tools window offers the ability to manage test standards including the ability to define custom tests,
favorite tests and add and remove new standards and standard upgrades via USB disk. An automatic
electrode clean function is included as a means of removing deposits from electrode surfaces. This window
also runs a test using the VCM100D/VCM80D voltage testers to check output voltage at the electrode
barrier.

The flag symbol is used as an icon representing language option. Simply use the right arrow button to
navigate to across the tabs tot he language symbol. Then up/down arrow buttons to select the required
language and press ‘OK’.

The battery symbol will be shown on PB models only.

14
Navigation and Character Entry
The keypad consists of arrow keys surrounding an
‘OK’ button used for navigating the screens and
selecting functions and options. These six buttons fully
control the instrument.

Within each user interface window the up and down

arrow buttons are used to navigate up and down the
functions listed on the left side of the screen.

On the PB models only, the ‘OK’ key either scrolls

through options associated with each function or enters a lower level window to perform a function.

Left and right arrow buttons navigate between tabs on the top level window for optimum speed. Individual tab
windows save the highlight function and return to the same position on each screen.

Users can navigate into lower level windows using the up/down arrow buttons and the ‘OK’ button to reach, for
example, the ‘Display Setup’ function.

The user navigates to ‘Display Setup’

and presses ‘OK’ to get to the display
setup window. The up/down or the
left/right buttons adjust brightness
with a bar indicator showing
brightness percentage. The ‘OK’
button is used to set brightness after
adjustment and subsequent return to
the settings window.

The following images illustrate this function for the PB models:

A virtual QUERTY keypad that facilitates alphanumeric entry to specify asset ID, filename and custom test name. A
character is selected by navigating to it, current character shows with a blue background, and pressing the ‘OK’ button.
After typing the required characters the virtual keyboard ‘OK’ is selected to return to previous window.

Numeric entry is via a virtual keypad as shown to the right. Digit entry is the same as the full virtual keypad with a
keypad ‘OK’ activating a return to previous window.

The image illustrate the function for the AF models.

Keypad entry is via the 12 button keypad. If an alpha character is required the
relevant key is pressed until the character appears in the screen entry field.
Uppercase alpha characters are default and lower case mode is entered by
pressing the shift ( ) key before entering the desired character. Pressing shift
again will enter numeric digit entry mode.

15
Favourite test standards
It is important to setup favourite test standards from the standards library to avoid navigating thorough the entire
list each time you want to change to a different test. To do this navigate to the ‘Tools’ top level window and select
‘Manage test standards’. Then move down to ‘Select favourite tests’ and choose only those tests which you require,
making sure you have the most recent version of each test, unless you specifically want to use an old test standard.
Tests are greyed out when selected. Simply return to the previous screens to save your selection. The screens below
illustrate this process.

Performing a breakdown
Select the ‘Home’ tab window using the arrow keys and ‘OK’ button. This
window offers a summary of information required for a measurement. The
following image shows a typical setup with the selected standard test, the
test identification or asset ID comprised of an asset number and two digit
serial number, the type of oil, required electrode gap, electrode shape and
finally the stirrer.

When the user selects a particular standard only valid options are
presented with respect to gap setting, electrodes and stirrer options.

Navigation is simple; up and down arrow buttons move up and down the left side of the window whilst options for
each line can be scrolled through using the ‘OK’ key, or information
entered in the case of Test ID.

Test in progress
During a test the screen flashes red warning HV symbols to remind the
user that a high voltage test is in progress. As a safety measure, any key
press will immediately halt the test.

The electrode potential difference is displayed as it ramps up in

over-sized digits to emphasise the presence of high voltage.

Between tests there is a dwell time and possibly a stirring action. A count
down timer indicates period of dwell or stirring remaining.

16
Test results
At the end of any test results are shown on the screen. A typical example is the ASTM D 1816-12
test. This image shows the complete on-screen information presented to the user however the
screen size is naturally smaller so a slider function enables the user to navigate through the result
and print it if required.

All screen based test results accommodate 10 tests but tests with less than 10 results use only the
relevant data to produce statistics i.e. statistics of mean breakdown voltage, data dispersion, range
and standard deviation.

Printing a result can be selected as default or from the PRINT function within the results window.

17
Custom tests
Custom tests are tests that can be defined by a user by giving the user control over the range of parameters set in a
test. Three custom tests have been pre-programmed for user definition;
„„Custom (5) – this test contains 5 successive breakdown tests

„„Custom (6) – this test contains 6 successive breakdown tests

„„Custom (10) – this test contains 10 successive breakdown tests
„„

Navigate to the Tools top level screen as illustrated below. Select, “Manage Test Standards” by pressing the OK button.
Go down to, “Edit Custom Test Parameters” and press the OK button. The custom parameters screen shows a set of
variables that control a breakdown test. Each variable is user settable, simply navigate down to the required setting,
press the OK button and proceed to change the value as required. For numeric entry on the OTS AF models the
decimal point can be entered by quickly pressing the digit ‘1’ twice. So to enter 2.5 mm gap setting the user enters the
following sequence:
„„2

„„1, 1
„„5

„„OK

In the customs test parameters screen ‘set max. kV’ may appear as, ‘set kV (max. xxx)’ in certain versions of firmware.
All entry fields in the custom test parameters screen are range checked to ensure it is valid. When all values are set the
user navigates back to the Tools screen via the RETURN function. The user should ensure that the relevant custom tests
are selected as favorite tests before leaving the manage test standards screen.

18
Basic memory functions
The internal memory is limited to fifty test records where a record represents a full result of one of the programmed
standard tests. Best practice is to backup internal results on a daily basis by saving onto a USB memory device. When
saving to USB memory device, a filename in the format of a maximum eight characters is required and the filename
entered must only contain characters A-Z, a-z and 0-9.

Memory functions are accessible from the files menu and include the following:
„„Save

„„Recall

„„Delete

„„Print last result

The user can select between internal memory and a USB memory device for the
save, recall and delete functions. After selection of a memory location the relevant
files are displayed on screen. Navigation is via the arrow keys as follows:

Up and down arrow move up and down one item at a time. Left and right arrows implement a page up and page
down function to assist navigation where large numbers of file are present.

In the delete function window the user can select all, deselect all or select one file at a time. Select a single file by
navigating to the file (blue highlight) and pressing OK to select (red highlight changing to grey when navigating away
from the selected file.)

The recall function operates on one file at a time.

Transfer results to USB flash drive

Users may want to copy results from internal memory to a USB memory device as either an end-of-day procedure or
whenever the 50 result file limit is reached. The following procedure will backup files to a USB memory device:

1. From the file menu, select ‘Save’

2. Then ‘Select USB’
3. Enter a filename using only characters A-Z, a-z and 0-9 via the virtual keypad on the PB models or the actual keypad
on the AF models, and return to save function screen
4. Navigate down to ‘Select Results’ – a full list of internally saved results are presented by TestID.
5. Select required results and then ‘SAVE’ to transfer the results to filename (as entered) on the memory device.
6. Navigate back to top level functions and remove the memory device (if required)

19
Print quality and changing paper
The printer cover is removed by turning the two fasteners through a quarter turn and pulling the panel off.

The printer ribbon may need to be moved on to improve print quality. To do this, remove the printer cover and turn the
right hand rotary winder in direction indicated on the ribbon case. To change the printer ribbon, simply press the ribbon
assembly where it says, “PUSH EJECT,” to remove the old ribbon and replace with a new one. The part is an Epson
ERC-09, Megger part number 25995-002.

Paper is fed into the housing with the lose paper facing the rear of the
instrument. Ensure that the paper is neatly cut and not curled up at
the end.

Holding the end of the paper roll, insert the paper under the cross bar and into the printer slot as shown (blue arrows)
in the drawing opposite. Press the print feed key repeatedly until the paper is just visible feeding through the print
mechanism.

Replace the printer front cover by first locating it at the base of the panel and secure it with the fasteners which are
turned back a quarter turn to secure the panel in place. Finally press the paper feed button to advance the paper
through the front cover paper slot.

Vessel and Electrodes

The oil test vessel and electrodes require no maintenance other than
cleaning. Electrodes can be unscrewed and replaced with another shape
electrode. Electrodes should be examined regularly to ensure no pitting has
occurred and the electrodes renewed where pitting is evident.

The instrument includes a built in electrode cleaning function which can

be activated from the tools menu. This function will perform 24 sequential
breakdowns to remove deposits on electrode surfaces.

VCM100D/VCM80D
The VCM100D/VCM80D are not user serviceable items but may require periodic cleaning using a clean cloth dampened
with Isopropyl Alcohol (IPA).

Test vessel motorised stirrer

Megger’s motorised stirrer is integrated into a modified lid assembly and simply replaces the vessel lid. Power is
connected via a flush mounted rear insert and is disconnected as the stirrer assembly is lifted. This unit is not user
serviceable.

20
Preventive maintenance

General
The OTS is a HV instrument generating up to 100 kV (model dependent) and is not user serviceable. The user should
ensure that the lid is not cracked or distorted before use. The only internal part of the instrument that is accessible to
the user is the printer paper housing allowing renewal of paper and ribbon when required. Opening the instrument
is strictly forbidden and will constitute a breach of warrantee. There is no need for any tools to be used with this
instrument other than the supplied gauges and magnetic bean retriever. Printer cover locks can be turned using a
suitable coin.

Cleaning
To clean the outer surfaces of the instrument, first disconnect from line power and then wipe the instrument using a
clean cloth dampened with Isopropyl Alcohol (IPA).

The user must ensure that the test chamber is always kept clean, particularly prior to a test. Wipe away any spilt oil in
the chamber or on the outside of the test vessel with a lint free cloth. When a lot of oil is spilt in the test chamber the
unit is designed with a drain facility at the rear. Simply unclip the clear tube and drain oil into a beaker or other suitable
container.

To clean the inside of the test vessel follow the instructions given in the relevant test specification or, in the case of no
instructions, cleaned with a small volume of the next sample of oil to be measured.

Care for OTS electrodes

Brass electrodes supplied with the Megger oil test sets will show signs of deposits built up from insulating oil
breakdown testing. If left they will oxidise and appear dull.

New electrodes
Megger electrodes are supplied in a kit with gap gauges and magnetic stirrer beans and retrieval stick. The electrodes
have different shapes but are cared for in the same way. If new electrodes require cleaning, isopropyl alcohol (IPA) may
be used to clean them off. It is advisable to immerse the electrodes in clean insulating oil for a couple of hours prior to
use.

Electrode storage
Electrodes may be stored in a suitable container or immersed in clean mineral insulating oil. Electrodes in a test vessel
left to stand overnight may be left with the last oil sample tested in the vessel.

Cleaning oxidised/dirty electrodes

Dirty electrodes may be cleaned with a clean, soft cloth and brass cleaner but care should be taken to use minimal
pressure to avoid removal of excessive electrode material. After removing the dirt clean the electrodes with a clean
cloth and IPA. It is advisable to immerse the electrodes in clean insulating oil for a couple of hours prior to use.

If electrodes are pitted or scratched they should be discarded and new electrodes fitted.

21
Technical Specification
The following technical specifications apply to the OTS AF and PB models, unless otherwise stated:

Test voltage PB models:

0 to 60 kV rms maximum (30 kV - 0 - 30 kV)
0 to 80 kV rms maximum (40 kV - 0 – 40 kV)
AF models:
0 to 60 kV rms maximum (30 kV - 0 - 30 kV)
0 to 80 kV rms maximum (40 kV - 0 - 40 kV)
0 to 100 kV rms maximum (50 kV - 0 - 50 kV)

Voltage resolution 0.1 kV

Voltage accuracy ±1% ±2 digits
Vessels 400 ml (standard)
150 ml (option)
Thermoplastic polyamide chamber provides precision electrode
alignment, adjustment wheels lock electrodes in position
Temperature sensor resolution 1 ºC
Power supply Line voltage/power 90 to 264 VAC, 300 VA
Line frequency 48 / 63 Hz
Fuses 2 x 4 A CFST ceramic, 20 mm x 5 mm, for 250 V
Batteries (PB model option only) Lead Acid 2 x 12 V 4 Ah, or NiMH 24 V 2 Ah
DC power supply (PB model only) 12 VDC, 60 VA – fitted with battery option,
used to charge battery only
Internal printer (optional) Dot matrix impact printer with graphical output
Paper 57.5 mm wide, weight 52 gm per roll
Epson black ribbon cassette ERC-09B
Protection Safety interlock on test chamber
Discharge barrier on polycarbonate test chamber cover
Display 320 x 240 QVGA colour display with backlight
Dimensions (W x H x D) OTS80PB 520 mm x 380 mm x 250 mm
OTS60PB 520 mm x 330 mm x 250 mm
OTS100AF 520 mm x 420 mm x 290 mm
OTS80AF 520 mm x 420 mm x 290 mm
OTS60AF 520 mm x 420 mm x 290 mm
Weight OTS80PB
no battery 20.5 kg
NiMH battery 21 kg
Lead acid batteries 23.5 kg
OTS60PB
no battery 16.3 kg
NiMH battery 16.8 kg

OTS100AF 30 kg
OTS80AF 30 kg
OTS60AF 30 kg
Operating temperature 0 ºC to +50 ºC
Storage temperature -30 ºC to +65 ºC

22
Humidity 80% RH at 40 ºC operation
95% RH at 40 ºC storage
Altitude 1000 m
Safety Designed in accordance with IEC61010
EM Light industrial IEC 61326-1 Class B, CISPR 22, CISPR 16-1
and CISPR 16-2

VCM100D/VCM80D Voltage check meters

The VCM100D and VCM80D are OTS accessories that enable the voltage output of the oil test set to be checked by
measuring the actual voltage at the HV electrodes. The calibration meters fit in the oil test set chamber in place of a
standard vessel and are designed to ensure that the load on the OTS transformer is similar to the load during an oil
dielectric strength test.

Meter type Proprietary 100 kV/80 kV Megger OTS voltmeter with

4 seven-segment digit digital readout

Accuracy at 23 °C 2.0% plus 2 digits to 50 kVrms

2.5% plus 2 digits > 50 kVrms to 75 kVrms
3.0% plus 2 digits > 75 kVrms to 100 kVrms
(VCM100D only above 80 kV)
Operational temperature range 0 °C to 40 °C
Storage temperature range 30 °C to +70 °C
Operational humidity range 50% RH at 20 °C
Storage humidity range 93% RH at 40 °C
Safety The meter is only approved for use with Megger oil test sets
Dimensions (W x H x D) 250 mm x 150 mm x 115 mm
Weight 1.8 kg

Storage and transportation

The Oil Test Sets are precision instrument that generates HV to 100 kV and needs to be transported and stored
carefully.

For PB models, a transportation case is available as an option and required by customers wanting to transport the
OTS80PB or OTS60PB by road, rail or air. A soft, shoulder carry case is provided as an option with the OTS80PB or
OTS60PB. It opens up to facilitate running a test without removal of the instrument and provides two side pouches for
storage.

The unit should be stored in a room or area where the environment is within the temperature range of -30 ºC to 65 ºC
and maximum humidity of 95% at 45 ºC.

If the OTS80PB or OTS60PB has batteries fitted it should be fully charged at least once every three months to maintain
full battery capacity.

23
Only Megger supplied accessories can be used with the OTS range. Non approved
equipment cannot be guaranteed to work with the OTS.

Factory fitted accessories depending on order configuration

„„Internal printer
„„Electrode sets – IEC, ASTM and full electrode set containing one of each type of electrode
„„Vessel lid mounted impeller for use with 400 ml vessel(standard red impeller supplied, see page 9)
„„Power lead
„„PowerDB Lite CD

Optional accessories & spares

„„VCM100D voltage check meter 1001-105

„„VCM80D voltage check meter 1001-801
„„Vessel assembly 400 ml (no electrodes) 1001-473
„„Vessel assembly 150 ml (no electrodes) 1001-474
„„Vessel
lid mounted impeller for use with 400 ml vessel 1001-102
n ASTM alternative propeller shaft assembly 1007-153
n IEC alternative propeller shaft assembly 1007-154
n Large red impeller
„„OTS super-user kit 1007-467
Included accessories:
n Vessel 400 ml assembly
n Vessel 150 ml assembly
n Stirrer lid assembly with three impellers
n ASTM alternative propeller shaft assembly
n IEC alternative propeller shaft assembly
n Large red impeller
n The Megger guide to insulating oil dielectric breakdown testing booklet
n Carry case
„„Electrode set IEC 156 1001-447
„„Electrode set ASTM D 877/1816 1001-478
„„Full electrode set – contains all electrodes 1001-479
„„Printer paper 25991-001
„„Barcode reader, USB 1001-047
„„Electrodes - Spherical (pair) 6220-484
„„Electrodes - Mushroom (pair) 6220-580
„„Electrodes - Cylindrical (pair) 6220-483
„„Electrodes- Non-standard cylindrical with
0,5 mm edge radius (pair) 6220-538
„„Electrode gauge set 1, 2, 2.5, 2.54, 4 mm 1002-144

24
Repair and warranty

The Test set circuit contains static sensitive devices, and care must be taken in handling the printed circuit board. If the
protection of a product has been impaired it should not be used, and be sent for repair by suitably trained and qualified
personnel. The protection is likely to be impaired if, for example, the product shows visible damage, fails to perform the
intended measurements, has been subjected to prolonged storage under unfavourable conditions, or has been exposed
to severe transport stresses.

New products are guaranteed for 1 year from the date of purchase by the user.
Note: Any unauthorized prior repair or adjustment will automatically invalidate the warranty.

Note: Please ensure when returning an instrument for repair or warranty it is adequately packed. It is
recommended that the original packaging is taken note of, or retained, in case it is required. The instrument
should be carefully boxed and protected, and then be securely strapped to a pallet. Please note that damage
caused in transportation due to poor packaging may invalidate a warranty claim.”

Instrument repair and spare parts

For service requirements contact:–

Megger Limited or Megger

Archcliffe Road Valley Forge Corporate Center
Dover 2621 Van Buren Avenue
Kent, CT17 9EN Norristown, PA 194
England U.S.A.
Tel: +44 (0) 1304 502243 Tel: +1 (610) 676-8579
Fax: +44 (0) 1304 207342 Fax: +1 (610) 676-8625

or an approved repair company.

Approved repair companies

A number of independent companies have been approved for repair work on most Megger products, using genuine
Megger spare parts. Consult the Appointed Distributor / Agent regarding spare parts, repair facilities and advice on the
best course of action to take.

Returning a test set for repair

If returning a test set to the manufacturer for repair, it should be sent freight pre-paid to the appropriate address. A
copy of the invoice and of the packing note should be sent simultaneously by airmail to expedite clearance through
customs. A repair estimate showing freight return and other charges will be submitted to the sender, if required, before
work on the instrument commences.

25
End of life disposal

WEEE
The crossed out wheeled bin placed on the Megger products is a reminder not to dispose of the product at the end of
it’s product life with general waste.
Megger is registered in the UK as a Producer of Electrical and Electronic Equipment.
The Registration No is WEE/HE0146QT

Batteries
The crossed out wheeled bin placed on the batteries is a reminder not to dispose of them with general waste at the
end of their life.

OTS60PB/ OTS80PB

THE OTS60PB is supplied with either no battery fitted or with a NiMH battery pack fitted.
THE OTS80PB is supplied with either, no battery fitted, a sealed lead acid battery, or a NiMH battery pack fitted.

All OTS variants have been fitted with a lithium Ion memory backup cell, 3V 220mAh CR2032 type. The CR2032
battery replacement should only be performed by a Megger authorised repair agent, who will correctly dispose of the
spent battery.

For end of life disposal only the CR2032 backup cell is located in the front panel module mounted behind instrument’s
display. These are classified as Portable Batteries and should be disposed of in the UK in accordance with Local
Authority requirements

The sealed lead acid battery replacement should be performed only by a Megger authorised repair agent, who will
correctly dispose of the spent battery.
For end of life disposal only, the sealed lead acid batteries are located behind the right hand end panel. These are
classified as Portable Batteries and should be disposed of in the UK in accordance with Local Authority requirements.

The NiMH battery pack replacement should be performed only by a Megger authorised repair agent, who will correctly
dispose of the spent battery.
For end of life disposal only, the sealed lead acid batteries are located behind the right hand end panel. Spent NiMH
batteries are classified as Industrial Batteries. For disposal in the UK contact Megger Ltd.

For disposal of batteries in other parts of the EU contact your local distributor. Megger is registered in the UK as a
producer of batteries. The registration number is BPRN00142

Declarations of conformity
Hereby, Megger Instruments Limited declares that radio equipment manufactured by Megger Instruments Limited
described in this user guide is in compliance with Directive 2014/53/EU. Other equipment manufactured by Megger
Instruments Limited described in this user guide is in compliance with Directives 2014/30/EU and 2014/35/EU where
they apply.

The full text of Megger Instruments EU declarations of conformity are available at the following internet address:
megger.com/eu-dofc

26
 M
Australia Sverige
Megger Pty Limited Megger Sweden AB
Unit 1, 11-21 Underwood Road Eldarvägen 4
NSW 2140 Box 2970
T +61 (0)2 9397 5900 SE-187 29 TÄBY
F +61 (0)2 9397 5911 T +46 8 510 195 00
E auenquiries@megger.com F +46 8 510 195 95
E SVinfo@megger.com
Dubai
Megger Schweiz
Dubai Megger AG
United Arab Emirates Ob. Haselweg 630
T +971 4 456 9057 5727 Oberkulm, Aargau
E mesales@megger.com T +41 62 768 20 30
F +41 62 768 20 33
Canada
Megger Thailand
110 Milner Avenue Unit 1 Megger
Scarborough Ontario M1S 3R2 30/46 Moo 13
T +1 416 298 9688 (Canada only) Nongprue, Banglamung
T +1 416 298 6770 Chonburi 20150
F +1 416 298 0848 T +66 860103395
E casales@megger.com E THenquiries@megger.com

France United Kingdom

Megger SARL Megger Limited
Z.A. Du Buisson de la Couldre Archcliffe Road, Dover
23 rue Eugène Henaff Kent CT17 9EN
78190 TRAPPES T +44 (0)1 304 502101
T +33 (0)1 30.16.08.90 F +44 (0)1 304 207342
F +33 (0)1 34.61.23.77 E uksales@megger.com
E infos@megger.com
USA
Deutschland Megger
Megger GmbH 4271 Bronze Way, Dallas,
Obere Zeil 2 Texas 75237-1019
61440 Oberursel T +1 800 723 2861 (USA ONLY)
T 06171-92987-0 T +1 214 333 3201
F 06171-92987-19 F +1 214 331 7399
E DEanfrage@megger.com E sales@megger.com

India USA
Megger (India) Pvt Limited Megger
501 Crystal Paradise Mall Valley Forge Corporate Centre
Off Veera Desai Road 2621 Van Buren Avenue
Andheri(w) Norristown, PA 19403
Mumbai - 400053 T +1 610 676 8500
T +91 22 26740468 F +1 610-676-8610 (USA ONLY)
F +91 22 26740465 E sales@megger.com

South Africa USA

PO Box 22300 Megger
Glen Ashley 4022 4064 State Highway 6 South
Durban College Station, TX 77845
South Africa T +1 979 690 7925
T +27 031 5646578 F +1 979 690 0276
F +27 031 5637990 E sales@megger.com

This instrument is manufactured in the United Kingdom.

The company reserves the right to change the specification or design without prior notice.

Megger is a registered trademark

Part No. OTS60PB--OTS80PB--OTS60AF--OTS80AF--OTS100AF_UG_en_V05 10/2017

www.megger.com

27