Capricorn Controls DA01EPM1-1 Data & Application Note Page 1 of 8

EPM72 Engine Protection Module

Genset Controls - Timers - Monitors - Trips - Battery Charging - Spares & Accessories - Custom Products

• All facilities as KSM72 ..... plus much more !

• (optional) Pin for Pin compatibility with RSM72

• (optional) Crank-Cut & Over-crank lockout

• (optional) Integral Hours Counter

Combining the convenience of manual operation with engine

protection against Low Oil Pressure (LOP), Coolant Fault (HET) and EPM72D
(optionally) Overspeed & / or an Auxillary Input, these Keystart
Modules are easily mounted into almost any control panel or
switchbox. Set in a compact 72mmsq DIN sized module they can be used with a wide range of engine driven
equipment.

The front panel has five ‘High Intensity’ LED’s indicating system status. The key switch provides…

PREHEAT (EPM72_J option Only)

Select Pre-Heat if required, just prior to starting the engine. Use it for the shortest possible
time to preserve charge in the battery (typically 10sec – but dependant on the ambient
temperature). Do not leave the switch in this position. (See page-3 for ‘Timed Pre-Heat’
options).

OFF / RESET Use to stop the engine and resets all Shutdowns. Always ensure that the engine is stationary
before restarting.

RUN Powers the unit, energises the fuel solenoid and starts the Hold-Off timer (T0). If the key
remains in this position for 25sec’s or more, the Hold-Off timer will elapse and the module
will latch out on ‘Low Oil Pressure’. To start the engine from an alarm condition, the key
must first be turned to the ‘OFF’ position for at least 1 second (see above).

START Hold in this position to crank the engine, releasing it to the ‘Run’ position as soon as the
engine ‘fires’. If the engine fails to start after approx. 10 sec’s return the key to the ‘OFF’
position, wait approx. 10 sec’s and try again. If the engine fails to start after three attempts,
turn the key to the ‘Off’ position and consult the manufactures Handbook.

Assuming that the engine ‘fires’, the keyswitch is released to disengage the starter motor; the set runs up to
normal speed and the Hold-Off timer (T0) is running. The tachometer circuitry (EPM72B or D) continually
monitors for Overspeed. When the hold-off timer has elapsed, the LOP and HET fault circuits are enabled. In the
event of a shutdown, the appropriate fault Led is lit, the Alarm output (if applicable) is activated, the Fuel &
Starter relays are locked out and the LOP & HET channels disabled (first-up interlock).

The 'close to –Ve on fault', Auxiliary input is always active as it is not inhibited by T0 or any other shutdown. If
T0 is required then select an EPM72 with the ‘T’ option (see page 5).

Designed & manufactured in England by Capricorn Controls

Telephone: +44 (0) 1295 272360 Fax: +44 (0) 1295 264766 E-mail: sales@ capricorn-controls.com
Page 2 of 8
ORDERING INFORMATION

Channel – 5 Pin Compatible

Model No. Connectors Overspeed Charge Fail ‘Lamp Only’ With

EPM72A One --- --- Yes KSM72A

EPM72B One Yes --- Yes KSM72B
EPM72C One --- Yes --- KSM72C
EPM72D One Yes Yes --- KSM72D
EPM72CV Two EPM72C + ‘Aux’ input + outputs for: Swt +ve & Alarm
* EPM72CZ Two EPM72CV + Timed Pre-Heat output
EPM72DV Two EPM72D + ‘Aux’ input + outputs for: Swt +ve, Alarm & Meter
EPM72DZ Two EPM72DV + Timed Pre-Heat output
EPM72D - / XX Dummy 2nd Connector for wiring, allowing later upgrade to RSM72, by changing modules
EPM72E As EPM72D + ‘Crank-Cut’ on running + ‘Overcrank’ Lock-out + Meter O/P
Options Features Term.

* EPM72 - A Open collector 'Alarm' output on term.7 (single connector builds only) 7
EPM72 - H Integral (LCD) 'Hours Counter'
♣ EPM72 - - M Magnetic Pick-Up (MPU) speed sensing in place of 'Main Alternator' frequency sensing. 9 & 10
EPM72 - - - R 'Active-Low' drivers for external lamps &/or relays via a separate 8-way (top) connector. a ---- h
EPM72 - - - - S 'Symbols' on front panel in place of text.
* EPM72 - - - - -T 'Active-Low' driver output at the end of T0 period (& no fault shutdown) 7
EPM72 - - - - - -V Pre-Heat terminated after T0 time (max. 25sec from crank-cut) to suit certain engines
♦ EPM72 - - - - - - X LED-1 to show 'Aux.' channel 'Status' in place of 'DC on'. Please specify 'overstick' label!
⊗ EPM72 - - - - - - - Y Pulsed output for Fuel pull-in coil. Typically for.YANMAR engines. 7

Input Phasing

EPM72 - - - Het (Cooling Fault) & Lop (Low Oil Pressure) are both 'closed to ground' (Batt -Ve) on fault
EPM72 - - - / HR 'Het Reversed' - open from ground (Batt -Ve) on fault
EPM72 - - - / LR 'Lop Reversed'- open from ground (Batt -Ve) on fault
EPM72 - - - / HLR 'Het & Lop Reversed' - {both of the above} - open from ground (Batt -Ve) on fault

NOTE: 1/ * & ⊗ These Models & Options are 'Mutually Exclusive' as they all use terminal 7, but for different functions!
These 'Active-Low' driver output(s) are open collector transistors, each rated at 40V / 150mA
2/ ♦ The ‘X’ Option is only available on EPM72 DV & DZ builds.
3/ ♣ The ‘M’ option is only available on the EPM72B--, EPM72D-- & EPM72E-- builds
4/ EPM72CZ & DZ builds, inhibit the Starter until the Pre-Heat time has elapsed
5/ ⊗ The ‘Y’ option is only available on EPM72CZ & DZ builds

SPECIAL BUILDS
EPM72 - - - / - - / X0? These 'X' numbers, indicate non-standard product, which has been manufactured to suit a
specific customer. They do not appear in any catalogues and may only be available to the original customer. When
re-ordering, please quote the full part number together with the 'Serial Number' of the original unit(s).

CUSTOMISED PRODUCTS
If you require spare or replacement units with 'Model Numbers' & / or 'Build Options' not listed here --- please
contact our sales desk for the latest price and delivery. Always quote the serial No. of the original unit.

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 Capricorn Controls DA01EPM1-1 Data & Application Note Page 3 of 8

CONNECTIONS
Always ensure that the correct wire sizes are used and that all terminals are tightened correctly.

Terminal Description Input / Output Connect To ------

1 LOP Low Oil Pressure -Ve Input Low Oil Pressure switch
2 HET High Engine Temp. -Ve Input High Engine Temp. switch
3 Starter Max. Load 16 Amps (resistive) * +Ve Output Solenoid or Solenoid Relay
4 Batt+ Supply +Ve Battery positive
5 Fuel Max. Load 16 Amps (resistive) * +Ve Output Solenoid or Solenoid Relay
6 Batt - Common DC -Ve supply Battery negative
7 (See text)
8 C.F. Charge Failure +Ve Output Charging Alternator (WL)
9 AC or MPU - Speed sensing 115/230VAC (Main Alternator or
10 AC or MPU+ Speed sensing Magnetic Pick-Up (see ‘Options’)

11 (Reserved for RSM72)

12 Meter + Analogue Meter Output +Ve Output RPM Meter / DC Voltmeter --- see text
13 Pre-Heat Open Collector Transistor *** -Ve Output Pre-Heat control relay
14 Alarm Open Collector Transistor *** -Ve Output Alarm control relay
15 Swt +Ve Switched +Ve Output ** +Ve Output To power, ‘Alarm’ relay etc.
16 Aux Auxiliary Shutdown -Ve Input Expansion Module(s) or Spare I/P
17 (Reserved for RSM72)
18 (Reserved for RSM72)
19 L.T. Lamp Test +Ve Input ‘Global’ Lamp Test circuits

NOTE : * De-rate to 14% for Inductive Loads (2.2A for Relay or (Solenoid) see below
** Limit to 500mA Maximum.
*** Limit to 300mA Maximum. Flywheel diode(s) should be connected across inductive Load(s)

WARNING: Fuel & Starter Outputs

Although the on board relays and are quite capable of directly switching small solenoids, we would recommend
that slave relays are always used as a matter of course unless both the Fuel & Starter Solenoid currents are known,
and are within the specification of the EPM72. In line with other manufacturers, we quote the Fuel and Starter
outputs as 16A (resistive) which relates to the contact ratings of the internal relays. However, as both Solenoids &
Relays are inductive loads this 16A rating must always be de-rated to 14%, that is maximum continuous current
of 2.2A to allow for a 'seven times' inrush, when the inductive load is energised.

WARNING: Voltages dangerous to human life

Voltages dangerous to human life may be present at some of the terminal connections of this unit. Ensure that all
AC and DC supplies isolated before attempting any connection / disconnection.

Noise Suppression Components

Both AC & DC inductive components (i.e. Relays, solenoids, etc) should be connected as shown --

Diode
+V For further information or advice -
‘C–R‘ AC DC Please contact the sales desk
Snubber COIL COIL

--V

Designed & manufactured in England by Capricorn Controls

Telephone: +44 (0) 1295 272360 Fax: +44 (0) 1295 264766 E-mail: sales@ capricorn-controls.com
Page 4 of 8

Basic Connections

Standard Low Oil Pressure sensor

1
Models
Cooling Fault sensor(s)
2
EPM72A
EPM72B 3 Starter
EPM72C Relay
EPM72D 4
* F1
EPM72E
5 * Fuel
Relay
+ Charging WL
6 Battery Alternator
--
7 See text

9
Main Alternator
40 – 280VAC
10

Toothed
--Ve 9
* * Flywheel

Signal
10
EPM72_M

Screened Cable
Magnetic Pick-Up

EPM72DV 11 Used on RSM72 Remote Start Modules *

EPM72DZ + --
ONLY 12 Meter
1mA / 75ohm Ammeter
13
Pre-Heat
Relay * Term.5 for RPM indicator .. or
Fuel + digital voltmeter for
14 Alarm
Relay
* Calibration purposes.

15 +V Output in RUN position

16 Auxiliary
Shutdown
Used on RSM72 Remote Start Modules
17 Batt -Ve
Close to Run
18 Open to Stop Lamp Test (optional)

19 *

NOTES : 1/ Items marked * are generally available ‘ex-stock’ from Capricorn Controls.
2/ Term.17 & 18, close for auto-start on RSM72. Pre-wire for upgrade path to Remote Start Module
3/ Low Oil Pressure & Cooling Fault sensors are shown ‘close to ground’ on fault ……. See text
4/ Cooling Fault could be ‘High Engine Temp’ & / or ‘Low Coolant Level’
5/ Fuse F1, rate at 5A A/S if Fuel & Starter slave relays used or 10A A/S if only starter slave fitted
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 Capricorn Controls DA01EPM1-1 Data & Application Note Page 5 of 8

Wiring Instructions for Specific Build 'Options'

1/ EPM72--M-- Speed sensing via Magnetic Pick-Up (in place of main alternator frequency sensing).

Term. 9 (-Ve) and term.10 (signal) should be connected to the Magnetic Pick-Up terminals via a screened cable.

Always ensure that --

(a) The screen is ONLY connected to term.9 and if wired via a terminal block, that the integrity of the screen is
maintained.
(b) If one of the Magnetic Pick-Up connections is connected to it's case, that this one is connected to term.9
(c) The correct gap is set between the Magnetic Pick-Up and the Flywheel teeth.

2/ EPM72--R-- Seven, 'active-low' drivers allow external lamps &/or relays (150mA / 30VDC max each
output) to be connected via an 8 way (top) connector. Typical applications include: remote indication
(i.e. using an LPM72 Lamp Module) and volt-free contacts for 'Dial-Out' Alarm Systems.

(EPM72) term.15
A
a RL1 Low Oil Pressure A
Bb RL2 Cooling Fault B
Cc RL3 Overspeed C
Dd RL4
Auxiliary D
Ee RL5
Fail to Start E
Ff Running F
RL6
Gg Alarm G
RL7
Hh (Lamp Test) H
Do not connect
Batt +Ve
term.15
(EPM72DVR or DZR)

4/ EPM72--T-- 'Active-Low' driver output (on term.7) at the end of the 'T0' hold-off timer period

RSM72 - - T -

16 7
Auxiliary I/P

Connected as shown above, the 'Aux.' channel is subject to the 'T0' timer, and provided with 'First-up
Interlock'. This 'T0' output is capable of sinking 150mA / 30VDC and could be used to drive an
external relay (connect to term.15 SW+ or term.5 Fuel +).

Designed & manufactured in England by Capricorn Controls

Telephone: +44 (0) 1295 272360 Fax: +44 (0) 1295 264766 E-mail: sales@ capricorn-controls.com
Page 6 of 8

5/ EPM72 - - A Active Low Alarm Output

5 Batt +Ve
Slave
6
Relay
‘ A ‘ Option : Alarm Output 7

6/ EPM72 - - J Active High Manual Pre-Heat Output

5 Batt -Ve
Slave
6
Relay
‘ J ‘ Option : Manual Pre-Heat 7

7/ EPM72 - - Y Active Low (1sec) Pulse Output for fuel solenoids with separate ‘pull-in’ coil.

5 Fuel + to ‘Hold’ coil

Slave
6
Relay
‘ Y ‘ Option : 1 sec Pulse O/P 7

Here the Slave Relay will be used to switch Batt +Ve (at perhaps > 30A, for 1 sec) to the fuel solenoid
‘Pulse’ Coil. The ‘Hold’ coil current would normally be within the rating of the on-board relay.

Connection to an EXM72 Expansion Module

The EXM72 Expansion Module should be connected as shown. It provides up to four shutdown
channels and incorporates its own T0 Timer and a wealth of other features.

EPM72DV or DZ EXM72
Remote Start Module Expansion Module

Fuel+ 5 4 +Ve

Aux 16 7 INT

Alarm 14 9 HoldOff

Please refer to the EXM72 ‘Data & Application Note’ for further information

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 Capricorn Controls DA01EPM1-1 Data & Application Note Page 7 of 8

FAULT FINDING ----- EPM72 BASED SYSTEMS

Always check the ‘obvious’ first ----
♦ System correctly wired
♦ Correct EPM72 type fitted for the specific application
♦ EPM72 suitably calibrated
♦ All connections use suitably rated cables to comply with all appropriate regulations.
♦ All terminal screw connections tight.
♦ Battery(s) charged, in good condition, clean & tight connections and of the correct voltage
♦ The Module MUST be fitted in a control panel with adequate protection from extremes of Temperature, Humidity &
Vibration

WARNING - Incorrect wiring could damage the module i.e. -

1/ Loose connections on battery negative (term.6) & / or battery +Ve (term.4)
2/ Connecting any ‘Active low’ outputs (i.e. Pre-Heat, Alarm, etc.) directly to a positive supply.
3/ connecting any positive DC outputs (i.e. Starter, Fuel, Exc.+, etc.) directly to a negative supply.
4/ connecting any DC terminals to an AC supply.

• Unit Dead - set will not start :

Check for battery supply on term.4(B+) and term.6(B-) of the EPM72 using a DC voltmeter or by shorting term.4 to
term.19 (lamp test) [EPM72DV or DV models] and observing if the Led’s light.
• False tripping of Overspeed shutdown :
(a) Module requires calibration (see below)
(b) Open-circuit probe (magnetic pick-up version ONLY). Always use a screened cable where the screen is connected to
Batt-Ve at the controller end only.
(c) Engine ‘over-speeding’.
(d) External relays and Contactor coils may require noise suppression components (see page 2).
• Fuel operates but no Starter :
(a) Preheat timer set near maximum (50secs), wait for this time to elapse.
• Engine starts correctly and then shuts-down on ‘Over-Crank’ :
(a) Short-circuit probe or probe too far from flywheel teeth (magnetic pick-up version ONLY).
(c) AC sensing version - short-circuit, open-circuit or with a voltage <50VAC or frequency incompatible with the
EPM72 type fitted.
• No Pre-Heat output [EPM72DZ]: Pre-Heat timer (0 - 50 sec) set near minimum, adjust to suit application.
• Low oil pressure shutdown : Faulty pressure switch, incorrect type or trip setting
• Cooling Fault (High engine temp.) shutdown : (b) Faulty temperature switch, incorrect type or trip setting
(c) Incorrect EPM72 type for use with Temperature switch fitted
• Charging Alternator fails to excite :
(a) incorrect type of EPM72 fitted
(b) rear mounted 82R resistor damaged, missing or too high a value (may require 47R on certain 12VDC Alternators).
(c) charge fail (term.8) not connected to WL. connection on the charging alternator
• Overspeed and / or Nominal-Speed Calibration :
(a) Connect a digital (or other D.C voltmeter) to term.12 (meter +) and battery negative
(b) Run engine at or close to normal speed, measure & note the actual frequency (or speed using a tacho)
(c) Calculate: Meter output (at required Overspeed) = OS / Nominal x 2.50 (i.e. [57Hz / 50Hz] x 2.50V = 2.85V)
(d) Set ‘Overspeed Trip’ pot fully anti-clockwise, adjust the ‘Speed Cal’ pot until the meter reads 2.85V
(e) Slowly, wind the ‘Overspeed Trip’ pot clockwise until the unit (just) shutsdown on Overspeed.
(f) Wind ‘Cal’ potentiometer 3 turns anti-clockwise. Repeat (b).
(g) Adjust Cal pot for meter output = Actual / Nominal x 2.50V (i.e. [52Hz / 50Hz] x 2.50V = 2.60V)

Designed & manufactured in England by Capricorn Controls

Telephone: +44 (0) 1295 272360 Fax: +44 (0) 1295 264766 E-mail: sales@ capricorn-controls.com
Page 8 of 8
SPECIFICATION
Supply
12 / 24V Single range supply, operating from 6V to 30VDC
Drop Out : < 4 VDC Absolute maximum supply : 40VDC

Speed Sensing
Magnetic Pickup 600 Hz to 6 kHz at rated speed. (5V to 100Vac pk - pk)
Alternator 50 Hz to 400 Hz at rated speed. (40V to 280V Rms. absolute Maximum)

User Adjustable Functions

Pre-Heat Timer 0 - 50 sec (set at minimum, unless requested otherwise) [EPM72CZ or DZ]
Over-crank Delay 7 - 24 sec (set at 15sec, unless requested otherwise) [EPM72E]
Hold-Off Timer 5 - 25 sec (set at 25sec, unless requested otherwise)
Speed Calibration --- Set ‘Cal’ potentiometer for meter output = 2.50Vat Nominal Speed EPM72B, D or E]
Crank Cut Threshold 15 - 60% of Rated Speed (set at 40% unless requested otherwise) [EPM72E]
Overspeed Trip Level 102 - 125% of Rated Speed (set at 117% unless requested otherwise)
General
Ambient temperature -100C to +550C Operating, -250C to +700C Storage
Construction
Through panel fitting, 72mm sq. DIN standard case. Reverse screen-printed “LEXAN” front panel.
Printed Circuit Boards are varnished as standard.

Dimensions
Notes:
1/ Not to Scale
2/ All dimensions in mm
3/ Panel cut-out
68 x 68 mm
72

72 152

MOUNTING
The module must be fitted into a suitable control panel that provides adequate protection from the
extremes of Temperature, Humidity & Vibration. If the control panel is set-mounted then suitable
‘Anti-Vibration’ mounts MUST be used
Note: If specific information or a replacement unit is required, please ensure that the ‘Serial Number’ of the original unit is
quoted.

CAPRICORN CONTROLS LIMITED

INDUSTRIAL ELECTRONIC ENGINEERS
SPECIALIST CONTROLS FOR ENGINE APPLICATIONS
Thorpe Close, Banbury, Oxon., OX16 4SW. England
Tel: +44 (0) 1295 272360 Fax: +44 (0) 1295 264766
E-mail: sales@capricorn-controls.com Web: www.capricorn-controls.com
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E. & O. E. The Proven Solution to Power Controls DA01EPM1-1