SR4 GENERATOR MOUNTED CONTROL PANEL FOR SPARK IGNITED (SI) E Caterpillar

Components

Usage:

Location Of Components

NOTE: For schematics and wiring diagrams, refer to the Schematics And Wiring Diagrams section in this manual.

NOTE: For specifications on components located on the engine, refer to the Engine Service Manual.

Control Panel
(1) Panel light (PL). (2) AC voltmeter (ACV). (3) Ammeter voltmeter phase selector switch (AVS). (4) AC ammeter (ACA). (5) Optional modules. (6) Start/Stop modules. (7) SI Engine control shutdown light (SESL). (8) Voltage adjust rheostat (VAR). (9) Oil pressure gauge (OPG). (10) Frequency meter (FM). (11) DC voltmeter (DCV). (12) Water temperature gauge (WTG). (13) Governor switch (GS) or Speed adjustment potentiometer (SP). (14) Panel light switch (PLS).

Start/Stop Modules
(15) Automatic Start/Stop module. (16) Manual Start/Stop module.

Optional Modules
(17) Synchronizing lights module (with reverse power relay). (18) Synchronizing lights module. (19) Alarm module, NFPA 99. (20) Alarm module, NFPA 110.

Control Panel Door (Rear View)
(1) Panel light (PL). (2) AC voltmeter (ACV). (3) Ammeter voltmeter phase selector switch (AVS). (4) AC ammeter (ACA). (5) Optional modules. (6) Start/Stop modules. (7) SI Engine control shutdown light (SESL). (8) Voltage adjust rheostat (VAR). (9) Oil pressure gauge (OPG). (10) Frequency meter (FM). (11) DC voltmeter (DCV). (12) Water temperature gauge (WTG). (13) Governor switch (GS) or Speed adjustment potentiometer (SP). (14) Panel light switch (PLS). (21) Frequency meter resistor (FMR).

Start/Stop Modules (Rear View)
(15) Automatic Start/Stop module. (16) Manual Start/Stop module.

Optional Modules (Rear View)
(17) Synchronizing lights module (with reverse power relay). (18) Synchronizing lights module. (19) Alarm module, NFPA 99. (20) Alarm module, NFPA 110.

Subpan
(22) Terminal board A (TBA). (23) Terminal board B (TBB). (24) Cycle crank module (CCM). (25) Cooldown module (CDM). (26) Electronic governor (EG). (27) Fuse 1 (F1). (28) Fuse 2 (F2). (29) Fuse 3 (F3). (30) Terminal board C (TBC). (31) Auxiliary relay (AUX). (32) Fuse 9 (F9). (33) Pulse width modulated speed signal converter (PWM).

Standard Components

For abbreviations list, and schematics and wiring diagrams refer to the section Schematic And Wiring Diagrams in this manual.

Ammeter-Voltmeter Phase Selector Switch

The ammeter-voltmeter phase selector (AVS) switch has four positions. Positions 1, 2 and 3 allows the operator to check generator output current and voltage for each of the phases 1, 2 and 3 respectively. AC current and AC voltage are checked on the AC ammeter (ACA) and AC voltmeter (ACV) respectively. There is no reading when the AVS switch is in position 0.

AC Ammeter

The AC ammeter (ACA) gives an indication, in amperes, of the current from each phase of the generator to the load. The AVS connects the ammeter to the current transformers (CT1, CT2 or CT3) on phases (T1, T2 or T3) respectively. The CT's transform the actual line current, in its respective phase lead, to a level (approximately 0 to 5 amperes) within the input range of the ammeter. The ammeter is calibrated to give an indication of the actual current flow in one phase of the generator.

AC Voltmeter

AC voltmeter (ACV) shows the potential difference (voltage) between phases T1-T2, T2-T3 or T3-T1 at positions 1, 2 or 3 respectively of the AVS.

Frequency Meter

The frequency meter (FM) shows the frequency in hertz (cycles per second) of the electricity made when the generator set is in operation. There is a direct relation between the frequency of the generator and the rpm of the engine, as shown in the following formula:

Voltage Adjustment Rheostat

Voltage adjust rheostat (VAR) is used to adjust the voltage output of the generator. This rheostat takes the place of the voltage level rheostat located on the generator voltage regulator assembly.

NOTE: On generators equipped with a generator mounted control panel, the jumper wire on the regulator terminals four and terminal seven must be removed to allow proper operation with the panel mounted rheostat.

Reference: Form No. SENR7968, SR-4 Generator; Operation Of Generator; Regulator Adjustment.

Oil Pressure Gauge

Oil pressure gauge (OPG) shows engine lubrication pressure in both kPa and psi. As soon as the engine starts and switch ESS (CT) closes, the oil pressure gauge is connected to battery voltage. There is a relation between the current flow in this circuit and the engine oil pressure read on the gauge. The oil pressure sending unit (OPSU) controls the current flow by a change in resistance according to the change in engine oil pressure.

Water Temperature Gauge

Water temperature gauge (WTG) shows the engine coolant temperature in both centigrade (°C) and Fahrenheit (°F). As soon as the engine starts and switch ESS (CT) closes, the water temperature gauge is connected to battery voltage. There is a relation between the current flow in this circuit and the coolant temperature read on the gauge. The water temperature sending unit (WTSU) controls the current flow by a change in resistance according to the change in coolant temperature.

Optional Components

For abbreviations list, and schematics and wiring diagrams refer to the section Schematic And Wiring Diagrams in this manual.

Automatic Start/Stop Module

This start/stop module has an engine control switch (ECS); an emergency stop pushbutton (ESPB) and four fault light indicators (OCL, OSL, WTL and OPL).

(1) Emergency stop pushbutton (ESPB). (2) Overcrank light (OCL). (3) Overspeed light (OSL). (4) Water temperature light (WTL). (5) Engine control switch (ECS). (6) Low oil pressure light (OPL).

Engine Control Switch

Engine Control Switch (ECS)

The engine control switch can be turned to four positions:

STOP position - When turned to this position from the AUTO or MAN positions, the contacts (9 and 10) (line 27) and (9 and 11) (line 26) open. When open the circuit to the run relay (RR) (line 25) is opened, this de-energizes RR and shuts down the engine. The ECS (5) also closes contacts (5 and 8) (line 29). This will keep battery (B+) to fault relays and fault lights that may have energized under a fault shut down condition. The engine control switch should be kept in the STOP position while a fault is being corrected.

OFF/RESET position - If a fault occurs, the engine will automatically shut down and light the correct shut down fault light. After the fault is corrected, the ECS (5) is turned to the OFF/RESET position to reset the fault relay and turn off the fault light. Power is still available to panel illumination lights and the fault lamp test circuit. This position can also be used for normal shutdown of the engine.

AUTO position - For standby application, the ECS (5) is turned to the AUTO position. In this position, the engine starts when a remote initiating contact (IC) (line 28) closes. This signals for an automatic start. When the IC contacts open, the engine will shut down, or if equipped with an optional cooldown timer the engine will run for the timer period then shut down.

MAN position - This position starts the engine. If a fault should occur, the panel will automatically shut the engine down and indicate the fault.

Emergency Stop Push Button

This button is red in color. It is used to shutdown the engine in an emergency. If ESPB (1) is used, overspeed light (3) will light. OSL (3) and any other fault lights cannot be reset by way of the engine control switch while ESPB (1) is pushed in. After ESPB (1) is pushed in, it will remain pushed in until reset.

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

To reset ESPB (1), rotate the knob in the direction shown on ESPB (1). The button will then move out from the panel.

NOTE: Before starting, check ESPB (1) mounted on the engine junction box. It has to be in the reset position also.

NOTE: The ESPB should not be used for normal shut downs.

Four Light Fault Board

There are four fault indicator lights and relays mounted on a printed circuit board assembly. This board is mounted in the automatic start/stop control module. If the engine should overcrank, overspeed, have a coolant temperature above the upper limit or have oil pressure below the low limit, one of the four lights will light. At the same time, the engine will be signaled to shutdown.

The light(s) remains lit with the ECS in the STOP position. It also remains lit and cannot be reset if the emergency stop push button (ESPB) is pushed in.

To reset the fault light(s), turn the ECS to the OFF/RESET position.

NOTE: If the fault is due to overspeed, the air shutoff solenoid (on the engine) and the speed switch (in the junction box) must be reset before starting the engine.

Each fault light indicator is a combination light and test button. A particular fault lamp can be tested by pushing in on the indicator light.

Manual Start/Stop Module

(1) Emergency stop pushbutton (ESPB). (2) Engine control switch (ECS). (3) Engine failure light (EFL).

The manual start/stop module has an emergency stop pushbutton (1), an engine control switch (2) and an engine failure light (3).

Engine Control Switch

Engine Control Switch (ECS)

The ECS (2) can be turned to three positions:

START position - This position is used to crank the engine. As soon as the engine starts and oil pressure is seen on the gauge, the ECS (2) is released and a spring returns the switch from the START to the RUN position.

NOTE: The ECS (2) should be held in the start position until oil pressure is enough to de-arm the oil pressure failure circuit. Even though the ECS (2) is held in the START position, crank termination will automatically occur when the engines reaches 400 rpm.

RUN position - This position is for normal operation after crank termination. In this position, the engine fault circuits are armed. If a fault occurs and the engine shuts down, the ECS (2) should be left in the RUN position until the fault is corrected.

STOP/RESET position - Under normal operation, this ECS (2) position is used to shut down the engine. When the engine shuts down due to a fault, the ECS (2) is turned to this position to reset the engine failure light (EFL) and permit an engine restart. In all positions, there is power to test the EFL and turn on the optional panel illumination lights.

Emergency Stop Push Button

This button is red in color. It is used to shutdown the engine in an emergency.

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

To reset the ESPB, rotate the knob in the direction shown on the ESPB. The button will then move out from the panel.

NOTE: Before starting, check the ESPB mounted on the engine junction box. It has to be in the reset position. When ESPB was used to shut down the engine, the air shutoff has to be reset.

NOTE: The ESPB should not be used for normal shut downs.

Engine Failure Light

In the manual start/stop module there is only one engine failure light (EFL) indicator. It will light for high water temperature, overspeed and low oil pressure. At the same time, the engine will shut down.

After the engine has shut down, the EFL indicator remains lit as long as the ECS remains in the RUN position.

When the fault has been corrected, turn the ECS to the STOP/RESET position to reset the EFL indicator.

NOTE: If the fault is due to overspeed, both the air shutoff solenoid (on the engine) and the speed switch (in the junction box) must be reset before starting the engine.

NOTE: The EFL indicator is a combination light and test button. It can be tested by pushing in on the indicator light.

Synchronizing Lights Module

Synchronizing Lights Module
(1) Synchronizing lights. (2) Plug. (3) Synchronizing switch.

The optional synchronizing lights module is located on the right side of the panel door (same location as for the optional alarm module). The synchronizing lights module is not used when the panel is equipped with either the optional 2301 governor or 2301 governor with pre-regulator.

Synchronizing lights (1) are used as an aid in paralleling units. Each light has one lead connected to the load and the other lead connected to the generator output. Together, they indicate when the voltages are in phase so the breaker can be closed to put the generator on line.

NOTE: For a complete explanation on how to parallel two units, make reference to form number SEBU6051, Operation and Maintenance SR-4 and SRCR Generators.

NOTE: For connection of the synchronizing light module and connection of resistor taps in the module, make reference to the section, Schematics And Wiring Diagrams.

Installation Of Synchronizing Module

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To avoid electrical shock and personal injury, all on line generator sets must be shutdown before installing or repairing the synchronizing module.

Make an orderly shutdown of all generators connected to the system. Then connect synchronizing module wires to the terminals as follows:

Load lead wire L1 to control panel terminal (L1).Load lead wire L3 to control panel terminal (L3).Wire T11 to the load side of fuse F11.Wire T12 to the load side of fuse F12.Wire T13 to the load side of fuse F13.

The customer is responsible for providing proper wire and fusing to connect L1 and L3 to the load side of the generator output circuit breaker. (Refer to the AC Schematic).

Adjust the connection of wires T11 and T13 on synchronizing resistors (SLR1) and (SLR2) respectively as required for your particular generator AC voltage. Refer to the chart that follows and the section, Point To Point Wiring Diagrams.

Synchronizing Resistor Tap Connection Chart
(4) Resistor taps.

NOTE: Remove the synchronizing module cover for access to the resistor taps.

EXAMPLE: For a generator with 400 volts line to line, T11 and T13 should be connected to tap B on the respective SLR.

Synchronizing Lights Module (With Reverse Power Relay)

For schematics and wiring diagrams, refer to the Schematics And Wiring Diagrams section in this manual.

NOTE: The synchronizing lights module (with reverse power relay) option looks and operates the same as the module without the reverse power relay with the exception of:

the reverse power relay (RPR) mounted on the back of the module.

the reverse power fault light (RPL) mounted on the front of the panel.

For information on the synchronizing lights module, make reference to the previous section on the Synchronizing Lights Module.

Introduction

The reverse power relay (RPR) provides system protection when the generator set is operating in parallel with another unit. If for some reason the engine loses power, the other unit in parallel will attempt to motorize (drive electrically) the engine and generator. Instead of power flowing OUT of the generator, power flows IN. This makes the generator a motor. This reverse flow of power could overload the other generators and the whole system.

Synchronizing Lights Module, With Reverse Power Relay
(1) Synchronizing lights. (2) Lens. (3) Synchronizing switch.

The reverse power relay (RPR) is a single phase relay which is energized by power flowing in only one direction (power into the generator instead of out). In a reverse power fault, the relay (RPR) (located on AC Schematic) closes its contact across RPR (5 and 6) (line 49) (located on DC schematic). This will cause the engine to shut down and the generator to be taken off line.

After the reverse power fault is corrected, the RPR and fault light must be reset by turning the engine control switch (ECS) to the RESET position.

The operation of the RPR can be tested by pushing the test button on the RPR while the generator is on load. The generator must be on line with at least 15% of rated kW.

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To avoid personal injury from electrical shock, be careful not to touch the high voltage terminal while adjusting the reverse power relay.

The relay trip point is field adjustable, but is normally factory set at approximately 15% of the generator rated kW.

Alarm Module

Alarm Module (NFPA 99 shown)
(1) Preliminary alarm lights (PAL). (2) Alarm silence pushbutton (ADS). (3) Alarm. (4) Lamp test switch (LTS).

NOTE: Reference the section, Schematics And Wiring Diagrams for the Alarm Module schematics.

The alarm module is an attachment located in the right side of the control panel. The purpose of the alarm module is to warn the operator of an engine condition before the condition gets bad enough to cause an engine shutdown or prevent the engine from starting. It will not shutdown the engine.

NFPA 99 Alarm Module

The NFPA 99 alarm module activates its warning system for conditions listed in the chart.

When an alarm condition occurs, the proper alarm switch (located on the engine) closes to complete the circuit which will light the respective warning light and power the audible alarm.

The audible alarm can be manually silenced by pushing the alarm disconnect switch (ADS) (line 13). When pushed, the switch ADS closes the circuit and energizes the alarm disconnect relay (ADR) (line 12). When energized, the relay ADR opens and closes its contacts across the following terminals:

ADR (7 and 4) (line 12) - This contact closes to lock in relay ADR.ADR (7 and 1) (line 11) - This contact opens to de-energize (silence) the audible alarm.

NOTE: The ADR will remain locked in until the condition which triggered the alarm is fixed. When fixed, the warning light(s) will go out and de-energize relay ADR. This causes contacts ADR (7 and 4) to open and contacts ADR (7 and 1) to close. Contacts ADR (7 and 1) close so the alarm is armed for the next condition(s).

Except for the low lube oil pressure alarm light (LOPL), all alarm circuits are armed all of the time. The LOPL is armed when the time delay relay (TDR) (line 4) energizes and closes contacts TDR (4 and 7) (line 6). Relay TDR energizes after the following occurs:

The engine, after reaching 400 rpm, closes the engines electronic speed switch (ESS) crank termination (CT) (line 4) and provides power to the time delay timer (TD).

After the adjustable 90 second delay elapses, the time delay timer (TD) energizes the time delay relay (TDR).

If the LOPL is armed (approximately 90 seconds after crank termination) and initial oil pressure is not built-up, the auxiliary switch (LOPAS 1) (line 5) remains closed to complete the circuit to fault indicators LOPL (line 6) and ALM (line 11).

A second optional low oil pressure auxiliary switch (LOPAS 2) (line 6) works in combination with an oil pressure step switch ESS (OPSS). At a certain engine speed the ESS (OPSS) starts a 90 second time delay, after which it closes. If oil pressure is not enough to have opened switch (LOPAS 2) then LOPAS 2 completes the circuit to the low oil pressure indicator (LOPL) (line 6) and the ALM (line 11).

The engine failure relay (ENFR) has a contact across normally open contacts ENFR (9 and 6) (line 11) to allow use of the audio alarm (ALM) (line 11) in case of an engine overspeed or an overcrank fault.

NOTE: This does not cause any of the warning lights on the alarm module to light.

When the engine has a normal shutdown. The ESS (CT) opens to cut power to timer (TD). The TD prevents relay TDR from energizing which opens the contacts TDR (4 and 7) (line 6) and keeps the alarm system from activating.

NOTE: If an automatic start/stop module is used, then the arming relay (AR) has a normally open contacts ADR (6 and 9) (line 5) placed between control panel terminals 18 and 70 (line 6). These contacts will close when relay AR in the automatic start/stop module is energized.

NFPA 110 Alarm Module

The NFPA 110 alarm module activates its warning system for conditions listed in the chart. The module will operate properly only when used with an automatic start/stop module.

NOTE: If the NFPA 110 alarm module is used with a manual start/stop module, the low lube oil pressure alarm light (LOPL) and audible alarm (ALM) will indicate a fault on startup and will turn off if the oil pressure builds to the proper level.

When an alarm condition occurs, the proper alarm switch (located on the engine) closes to complete the circuit which will light the respective warning light and power the audible alarm.

The audible alarm can be manually silenced by pushing the alarm disconnect switch (ADS) (line 23). When pushed, the switch ADS closes the circuit and energizes the alarm disconnect relay (ADR) (line 23). When energized, the relay ADR opens and closes its contacts across the following terminals:

ADR (7 and 4) (line 22) - This contact closes to lock in relay ADR.ADR (7 and 1) (line 21) - This contact opens to de-energize (silence) the audible alarm.

Except for the low lube oil pressure alarm light (LOPL), all alarm circuits are armed all of the time. The LOPL is armed when the arming relay (AR) located in the automatic stop/start module energizes and closes contacts AR (6 and 9) (line 6).

The engine failure relay (ENFR) has a contact across normally open contacts ENFR (9 and 6) (line 21) to allow use of the audio alarm (ALM) (line 21) in case of an engine overspeed or an overcrank fault.

NOTE: This does not cause any of the warning lights on the alarm module to light.

When the engine has a normal shutdown. The relay (AR) de-energizes opening contacts AR (6 and 9) and keeps the alarm system from activating.

Governor Switch

NOTE: The optional governor switch is available on control panels using the Caterpillar Hydra-Mechanical or PSG governors equipped with synchronizing motors.

After crank termination, the governor switch (GS) is enabled (allowed to operate), permitting a change in engine rpm (generator frequency). Move the switch up to increase rpm, down to decrease rpm. The governor switch makes it possible to adjust the engine speed (generator frequency) from the front of the control panel.

Speed Potentiometer

The speed adjust potentiometer (SP) is used with the optional 2301 and 1724/8290 governors to control engine speed. It's mounted in the panel in the location used by the governor switch in Hydra-Mechanical or PSG governor units. See section 2301 Governor, 2301 Governor With Pre-Regulator, and 1794/8290 Isochronous Governor. The engine speed can be adjusted up or down by turning the potentiometer.

2301 Governor, 2301 Governor With Pre-Regulator And 1724/8290 Isochronous Governor

These options provide a control panel mounted 2301 governor or a 1724/8290 Isochronous Speed Control Governor and are available for non-paralleling applications only. The 2301 option also provides a fuse (F4) or an optional pre-regulator which are mounted inside the control panel. The pre-regulator filters the B+ power to the 2301, preventing it from being damaged by voltage spikes. The pre-regulator should be used in abrasive environments where poor battery maintenance, loose battery terminals, or 32 VDC Nicad battery systems are likely.

The 2301 governor and the 1724/8290 Isochronous Governor have a speed potentiometer which is mounted in the panel front (in place of the optional governor switch).

Power (B+) is provided by the manual or automatic control panel at panel terminal (5), whenever the engine starts and runs.

For complete operation and troubleshooting information on the 2301 governor, refer to the module 2301 Electric Governors For Generator Set And Industrial Engines, Form No. SENR2928.

Cycle Cranking Module

Cycle Cranking Module
(1) Crank. (2) Rest

The cycle cranking module (CCM) is only provided with automatic start-stop panels.

NOTE: Jumper between terminals (26 and 36) on terminal board B (TBB) must be removed when the CCM is installed. Reference the section, Schematics And Wiring Diagrams.

The cycle cranking module (CCM) (line 6) has a relay and a timer. This attachment is used to cycle crank and rest the starting motor (SM). The relay controls the circuit to the starting motor magnetic switch (SMMS) which controls the circuit to the SM. The cycle timer controls the relay. The overcrank timer (OCT) (line 9) controls the time that the CCM is activated.

When run relay (RR) (line 25) contact (8 and 5) closes, battery positive is applied to CCM (line 6) from terminal (36). This activates the timer. The timer's normally closed (N.C.) contact stays closed. This allows the engine starting motor magnetic switch (SMMS) to energize and to activate the starting motor. When the cranking time is over, as set by the cranking potentiometer (1), the N.C. timer contact opens. This de-energizes the SMMS and the starting motor. The contact remains open through rest period. The rest period is set by timer rest potentiometer (2). When the rest period has expired, the N.C. timer contact closes again for a crank period. This cycle repeats until any of the following happens:

1. Electronic speed switch termination ESS (CT) opens the circuit, indicating that the engine is running.

2. Emergency stop pushbutton (ESPB) is pushed to open the circuit.

3. Run relay (RR) contact (8 and 5) (line 8) opens due to an overcrank fault or by turning the ECS to the OFF or STOP position.

NOTE: The crank potentiometer (P1) and the rest potentiometer (P2) are each adjusted to 10 seconds at the factory.

Cooldown Timer Module

The optional cooldown timer module (CDM) is available for auto start-stop panels. It allows the engine to run without load after the initiating contact (IC) (line 28) has opened across panel terminals (48 and 49) (line 28). This allows the engine to cooldown before shutdown.

NOTE: jumpers 49A to 49 and 48A to 48 on TBB must be removed upon installation of the CDM.

When the contact (IC) closes, the CDM output relay energizes to close its normally open (N.O.) contact (line 27) across panel terminals (48A and 49A).

When the contact (IC) opens, the CDM starts a time delay. The CDM relay remains energized during the time delay. When the time delay is finished, CDM relay contact across (48A and 49A) opens to de-energize the run relay (RR) and shutdown the engine. This delay is adjustable up to 36 minutes.

Panel Lights

Two optional panel illumination lights are located on each side at the top of the panel door. They are turned ON and OFF by the panel light switch (PLS), which is located on the right side of the panel door. The panel lights can be operated at any time regardless of engine control switch position or engine status.

Auxiliary Relay Module

The optional auxiliary relay module (AUX) (line 23) is available in auto start-stop panels. On normal start-up, electronic speed switch (ESS) crank termination (CT) closes to energize the AUX relay. The auxiliary relay module has normally open contacts (7 and 4), (8 and 5) and (9 and 6) and normally closed contacts (7 and 1), (8 and 2) and (9 and 3). Each contact is rated 10 amps at 28 VDC or 120 VAC. Contacts (2 and 8) and (8 and 5) are wired out to generator housing terminal strip points A1, A2 and A3 for easy customer access.

Engine Control Shutdown Light

The optional engine control shutdown light (ECSL) is located on the left side of the control panel. It is available only on 3500 low emission engines. Its purpose is to provide a warning light on the control panel which will indicate when the Caterpillar Inc. Electronic SI Engine Control (SIEC) has shutdown the engine. The ECSL is deactivated when the SIEC is de-activated.

DC Voltmeter

The optional DC voltmeter (DCV) is used when the generator set engine is equipped with an alternator charging circuit. The DCV indicates the charging voltage to the battery. The DC voltmeter is turned on when the engine control switch is in the AUTO or MAN positions on the Auto Start-Stop Modules. On the Man Start-Stop module the DC voltmeter is on when the engine control switch is in the RUN position.