15 - Pressure Relay For OLTC - (AKM - 35600 - Qualitrol)

1ZSC000498-AAZ en
ABB Power Technologies

Info. No.
From/Date PP/T/CO/TK 2007-03-15
Pressure relay
Background
The AKM Qualitrol 35600 is a pressure relay designed to meet the requirements of
On-Load Tap-Changer (OLTC) protection according to IEC 60214-1. It provides
fast response when the pressure exceeds one of several available preset levels and
is stable over a wide temperature range. In addition, its powder coated aluminum
housing is vented and well suited to the demands of outdoor environments. It
comes complete with a 3-way valve to allow for isolation of the OLTC while
checking the relay. A location is provided for padlocking the valve handle in the
(non-test) operating position. The test port is equipped with a gasketed cap for
additional sealing security.
Design
The sensing element is a phosphor bronze bellows, which expands in response to
rising pressure. It is fastened to a cantilevered switch actuator whose resistance is
controlled by an extension spring. When the pressure rises to the preset level the
actuator overcomes the extension spring force to operate the switch. The spring and
actuator are factory calibrated and are not intended to be field adjustable.
Fig. 1. Interior of pressure relay.
Postal adress Telecopier

ABB Power Technologies AB, Components Nat 0240 – 121 57
SE-771 80 LUDVIKA, Sweden Int +46 240 121 57
1ZSC000498-AAZ en
PP/T/CO/TK 2007-03-15
Page 2
Installing the relay

Overview
The valve is mounted to the tank using a 4 bolt mounting pattern (see Fig. 2) with a
flat sealing surface.
Fig. 2. Dimensions in mm.
The valve must be mounted on a vertical surface with the cable entry facing
downwards, or angled down from the horizontal, to assure proper venting.
The relay can also be delivered without a valve, for retrofit mounting at an existing
valve.
Step-by-step installation instructions:

1. Remove the cover from the pressure relay and connect the cables to the
terminal block.
2. Bolt the pressure relay flange onto a pre-arranged flange on the OLTC.
ABB Power Technologies 1ZSC00498-AAZ en
PP/T/CO/TK 2007-03-15
Page 3
Test procedure
Overview
With the valve handle (shown below) the pressure relay can be tested without
detaching it from the OLTC or creating a possible leak path. By moving the handle
to the test position the relay can be isolated from the OLTC, thereby allowing for
testing of the relay without risk of leaking. The pressure relay can then easily be
tested by applying air pressure, using a pump or squeeze bulb, to the test port on
the valve. The lever can also be padlocked in the service position. The insulation
resistance of the entire assembly can also be tested.
Valve handle
(in operating position)
R 1/8” test tap

Valve handle
(in test position)
Fig. 3. Test instruction.
Step-by-step test instructions

1. Set the valve lever to the test position.
2. Connect the air pump and the pressure gauge to the test tap on the pressure
relay.
3. Raise the pressure until the pressure relay actuates.
4. Read the pressure on the gauge and check against the pressure relay operating
point: maximum deviation is ± 10 %.
5. Check that the alarm signal resets to off when the pressure is lowered.
6. After finishing the check, turn the valve lever back to the service position.
Troubleshooting procedure
If the relay trips without apparent cause and all auxiliary equipment has been
checked and found to be functioning properly, the relay should be tested to assure
the insulation system is intact. Insulation resistance should be measured (1) between
C and N.O. contacts, and (2) with all contacts common and measured to ground.
Measurements are made at 500 V AC for 1 minute duration as per IEC 60255-5.
1ZSC000498-AAZ en
PP/T/CO/TK 2007-03-15
Page 4
Operating specifications
Operating pressure Models for 50, 100, 150 and 200 kPa setpoints
Proof pressure 300 kPa
Accuracy +/- 3 kPa
Response time Less than 15 ms at 20-50 MPa rate of rise
Ambient temperature -40 °C to +80 °C
Enclosure protection class IP55
Bellows pressure tightness 3 x 10-4 cc/sec
Mounting Two horizontally mounted orientations
Materials Housing and cover: powder coated aluminum
Bellows: phosphor bronze
Actuator plate: stainless steel
Wetted materials Phosphor bronze, brass, nitrile
Suitable for exposure to 110 °C
Cable diameter range 12.5mm – 15mm
Wire size 2.5 mm2 max.
Switch rating 5 A at 125 V AC resistive
3 A at 250 V AC resistive
0.8 A at 110 V DC resistive
0.2 A at 110 V DC, L/R = 40 ms
0.15 A at 125 V DC, L/R = 40 ms
0.1 A at 220 V DC, L/R = 40 ms
Dielectric strength 2000 V AC for 60 s, all contacts to ground
Insulation resistance IEC 60255-5
Calibration method None required

15 - Pressure Relay For OLTC - (AKM - 35600 - Qualitrol)

Uploaded by

Copyright:

Available Formats

15 - Pressure Relay For OLTC - (AKM - 35600 - Qualitrol)

Uploaded by

Document Information

Original Description:

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

15 - Pressure Relay For OLTC - (AKM - 35600 - Qualitrol)

Uploaded by

Copyright:

Available Formats

1ZSC000498-AAZ en

ABB Power Technologies

Fig. 1. Interior of pressure relay.

Postal adress Telecopier

Installing the relay

Fig. 2. Dimensions in mm.

Step-by-step installation instructions:

R 1/8” test tap

Fig. 3. Test instruction.

Step-by-step test instructions

You might also like