Systems Operation

Usage:

General System Description

The control panel is normally used for prime power operation and only operates with engine systems that are energized to run. The control panel will shut down the generator set when an engine fault occurs. At the same time, it will indicate by a fault lamp whether the fault is due to high water temperature, low oil pressure, engine overspeed, or spare fault (if connected).

Key Switch Operation

Key Switch In START Position

DC Schematic Of Key Switch In START Position

When the key switch (KS) is in the START position, KS contacts B and S (lines 11 and 10) and contacts B and R (lines 11 and 13) are closed. The starting motor magnetic switch (SMMS1) (line 9) is now energized. SMMS1 closes it's contact (line 6) to energize the pinion solenoid (PS1) (line 6). PS1 closes it's contact (line 5) to energize the starting motor (SM1) (line 5). The slave relay (SR1) (line 13) is also energized when the KS is in the START position. SR1 contacts 30 and 87 (line 7) close to energize the fuel solenoid (FS). Fuel is now provided to the engine during starting.

Key Switch In RUN Position

DC Schematic Of Key Switch In RUN Position

After the engine starts and the key switch (KS) is returned to the RUN position, KS contacts B and S (line 11 and 10) open. The starting motor magnetic switch (SMMS1) (line 9) is now de-energized. There is a mechanical block within the KS that prevents returning the KS to the START position without going to the STOP position first. This prevents cranking the engine while the engine is running.

With the KS in the RUN position, contacts B and R (line 11 and 13) close to keep the slave relay (SR1) (line 13) energized. SR1 contacts 30 and 87 (line 7) remain closed to energize the fuel solenoid (FS). Fuel is now provided to the engine.

The arming delay timer (ADT) (line 15) is also energized when the KS is in the RUN position. The ADT controls the amount of time that the oil pressure shutdown circuit is disabled after engine cranking. The ADT has an adjustable time delay (factory set at 15 seconds) that must elapse before the arming relay (AR) (line 15) is energized. The delay allows time for engine oil pressure to build-up after engine starting. During the delay, the activation of an oil pressure fault is prohibited. The control panel ignores the oil pressure switch (OPS) (line 43) during the delay time. After the time delay elapses, the ADT energizes the arming relay (AR). Contacts 4 and 7 of the AR (line 43) close. The oil pressure relay (OPR) (line 43) and the oil pressure light (OPL) (line 44) can now respond to an OPS contact closure for a low oil pressure shutdown fault.

NOTE: The fault light indicators (OSR, WTR and OPR) can be ON only when key switch is in the RUN position. To reset a fault light, turn key switch to the STOP position.

Key Switch In STOP Position

DC Schematic Of Key Switch In STOP Position

When the keyswitch (KS) is turned to the STOP position (line 10), KS contacts B and R (lines 11 and 13) open and slave relay (SR1) (line 13) is de-energized. SR1 contacts 30 and 87 (line 7) open and fuel solenoid (FS) (line 7) is de-energized. Fuel is no longer provided to the engine.

Engine Shutdown Operation

The engine can be shutdown manually or automatically. The most common method of shutting down the engine is by manually turning the key switch to the STOP position. For more information on this method, see the topic Key Switch In STOP Position.

When any one of the following conditions exist, the corresponding fault light will illuminate, the corresponding relay will energize and the engine will shutdown automatically.

* If the engine should overspeed as determined by the electronic speed switch (ESS).

* If the engine water temperature should rise above the upper limit of the water temperature switch (WTS).

* If the engine oil pressure should fall below the low limit of the engine oil pressure switch (OPS).

* If a shutdown condition should occur for the spare fault as determined by the customer.

Each of these shutdown methods (except spare fault) are described in the topics which follow. The conditions required for the spare fault shutdown are determined by the customer. However, the actual shutdown operates the same as the other faults.

Engine Shutdown Caused By Oil Pressure Fault

DC Schematic Of Engine Shutdown Caused By Oil Pressure Fault

When the key switch (KS) returns to RUN from the START position, KS contacts B and R (lines 11 and 13) close. The slave relay (SR1) (line 13) is now energized. SR1 contacts 30 and 87 (line 7) close to keep the fuel solenoid (FS) energized. Fuel is now provided to the engine.

The arming delay timer (ADT) (line 15) is also energized when the KS is in the RUN position. The ADT controls the amount of time that the oil pressure shutdown circuit is disabled after engine cranking. When the ADT is first energized a 15 second delay begins before the arming relay (AR) (line 15) is energized. After the 15 second delay the ADT energizes the AR. Contacts 4 and 7 of the AR (line 43) close. The oil pressure relay (OPR) (line 43) and the oil pressure light (OPL) (line 44) can now respond to a closed OPS (low oil pressure). During normal conditions, the 15 second delay allows the initial oil pressure to build-up which opens the oil pressure switch (OPS) (line 43).

If initial oil pressure does not build-up in the 15 second time delay, the OPS (line 43) will remain closed. Also, AR contacts 7 and 4 (line 43) are now closed. The circuit to the oil pressure relay (OPR) (line 43) and the oil pressure light (OPL) (line 44) is now complete. The OPR and the OPL are energized. OPR contacts (line 44) close and the OPR is latched. Also, OPR contacts (line 47) close to energize the engine failure relay (ENFR) (line 49). The normally closed ENFR contacts 1 and 7 (line 13) open to de-energize slave relay (SR1) (line 13). Without current to SR1, SR1 contacts 30 and 87 (line 7) open and fuel solenoid (FS) (line 7) is de-energized. Fuel is no longer provided to the engine.

While ENFR relay (line 49) is energized, the ENFR contacts 8 and 5 (line 52) close and provide power to the optional shunt trip coil (SHTC) (line 52). The optional SHTC opens the optional generator output circuit breaker.

Procedure To Restart The Engine

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To prevent personal injury due to accidental starting of the engine, disconnect the batteries before doing maintenance or repair work.

1. Turn the key switch (KS) to STOP. The OPL (line 44) turns off. The AR (line 13) de-energizes which opens AR contacts (line 43). With AR contacts (line 43) open, the OPR (line 43) de-energizes which opens OPR contacts (line 44). Also, OPR contacts (line 47) open to de-energize the ENFR (line 49). The ENFR contacts 1 and 7 (line 13) close to allow restart.

2. Correct the low oil pressure fault.

3. Close the optional circuit breaker.

4. The system is ready to start when the key switch is turned to the START position.

Engine Shutdown Caused By Water Temperature Fault

DC Schematic Of Engine Shutdown Caused By Water Temperature Fault

When engine coolant temperature becomes too high, the water temperature switch (WTS) (line 39) closes. The water temperature relay (WTR) (line 39) and the water temperature light (WTL) (line 40) are now energized. WTR contacts (line 40) close and the WTR is latched. Also, WTR contacts (line 48) close to energize the engine failure relay (ENFR) (line 49). The normally closed ENFR contacts 1 and 7 (line 13) open to de-energize slave relay (SR1) (line 13). Without current to SR1, SR1 contacts 30 and 87 (line 7) open and fuel solenoid (FS) (line 7) is de-energized. Fuel is no longer provided to the engine.

Procedure To Restart The Engine

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To prevent personal injury due to accidental starting of the engine, disconnect the batteries before doing maintenance or repair work.

1. Turn the key switch (KS) to STOP. When the engine cools, the WTS opens which de-energizes the WTR and turns OFF the WTL. WTR contacts (line 48) open to de-energize the ENFR relay (line 49). The ENFR contacts 1 and 7 (line 13) close to allow restart.

2. Correct the high water temperature problem. Allow the engine temperature to cool so that the WTS will open (reset).

3. Close the optional circuit breaker.

4. The system is ready to start when the key switch is turned to the START position.

Engine Shutdown Caused By Engine Overspeed Fault

DC Schematic Of Engine Shutdown Caused By Engine Overspeed Fault

When engine speed increases above the overspeed setting (118% of rated speed) of the electronic speed switch (ESS), ESS contacts 7 and 8 (line 35) close. The overspeed relay (OSR) (line 35) and the overspeed light (OSL) (line 36) are now energized. OSR contacts (line 36) close and the OSR is latched. Also, OSR contacts (line 49) close to energize the engine failure relay (ENFR) (line 49). The normally closed ENFR contacts 1 and 7 (line 13) open to de-energize slave relay (SR1) (line 13). Without current to SR1, SR1 contacts 30 and 87 (line 7) open and fuel solenoid (FS) (line 7) is de-energized. Fuel is no longer provided to the engine.

Also when the ENFR (line 49) is energized, ENFR contacts 6 and 9 (line 58) close. This resets the electronic speed switch (ESS) (line 57).

Procedure To Restart The Engine

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To prevent personal injury due to accidental starting of the engine, disconnect the batteries before doing maintenance or repair work.

1. Turn the key switch (KS) to STOP. ESS contacts 7 and 8 (line 35) open. The OSL (line 36) turns off and the the OSR (line 35) de-energizes. OSR contacts (line 49) open to de-energize the ENFR relay (line 49). The ENFR contacts 1 and 7 (line 13) close to allow restart.

2. Correct the engine overspeed problem.

3. Close the optional circuit breaker.

4. The system is ready to start when the key switch is turned to the START position.