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Governors America Corp. © 2021 Copyright All Rights Reserved
ESD5550-5570 Series Speed Control Unit
1-2021-E1
PIB1003
The engine’s exhaust smoke at start-up can be minimized by completing the following adjustments:
1. Switch 1 (SW1) controls the Lead Circuit. The normal position is ON. Move the switch to the OFF
position if there is fast instability in the system.
2. Switch 2 (SW2) controls a circuit designed to eliminate fast erratic governor behavior, caused by very
soft or worn couplings in the drive train between the engine and generator. The normal position is
OFF.
3. Move to the ON position if fast erratic engine behavior due to a soft coupling is experienced
LeaD cIrcUIT anD SofT coUPLInG
Droop is typically used for the paralleling engine driven generators. When in droop operation, the engine speed will decrease as engine
load increases. The percentage of droop is based on the actuator current change from no engine load to full load.
1. Place the optional external selector switch in the DROOP position. DROOP is increased by clockwise rotation of the DROOP adjust-
ment control.
2. After the droop level has been adjusted, the rated engine speed setting may need to be reset. Check the engines speed and adjust
that speed setting accordingly.
Though a wide range of droop is available with the internal control, droop level requirements of 10% are unusual. If droop levels experi-
enced are higher or lower than those required, contact GAC for assistance.
DrooP oPeraTIon
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ADJUSTMENTS (CONTINUED)
WIDe ranGe remoTe varIaBLe SPeeD oPeraTIon
Remote variable speed can be obtained with the an external potentiometer. A single remote speed adjustment potentiometer can be used
to adjust the engine speed continuously over a specific speed range.
1. Select the desired speed range and corresponding potentiometer value as detailed in section 4, ADDING A POTENTIOMETER. If the
exact range cannot be found, select the next higher range potentiometer.
2. Connect the speed range potentiometer as shown in WIRING Diagram.
3.
An additional fixed resistor may be placed across the potentiometer to obtain the exact desired range.
4. To maintain engine stability at the minimum speed setting, a small amount of droop can be added by turning DROOP adjustment CW.
5. At the maximum speed setting the governor performance will be near isochronous, regardless of the droop adjustment setting.
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METHODS OF OPERATION
One of two methods of operation for the ESD5550/5570 may now selected; starting at operating speed, or starting at idle.
1. Remove the connection between Terminals M & G.
2. Start the engine and accelerate directly to the operating
speed (Gen Sets, etc.).
3. Adjust the SPEED RAMPING for the least smoke on acceler-
ation from idle to rated speed.
4. If the starting smoke is excessive, the STARTING FuEL may
need to be adjusted slightly CCW.
5. If the starting time is too long, the STARTING FuEL may need
to be adjusted slightly CW.
This method separates the starting process so that each may be
optimized for the lowest smoke emissions.
1. Replace the connection between Terminals M & G with a
switch, usually an oil pressure switch.
2. Start the engine and control at an idle speed for a period of
time prior to accelerating to the operating speed.
3. If the starting smoke is excessive, the STARTING FuEL may
need to be adjusted slightly CCW.
4. If the starting time is too long, the STARTING FuEL may need
to be adjusted slightly CW.
5. When the switch opens, adjust the SPEED RAMPING for the
least amount of smoke when accelerating from idle speed to
rated speed.
STarTInG aT oPeraTInG SPeeD
STarTInG aT IDLe SPeeD
