AUTOMATIC START-STOP - TM-5-3895-349-14-P0857

OIL PRESSURE

WATER TEMPERATURE

AMMETER

AMMETER - The ammeter should register in the charging

In cold weather the temperature-gauge may fluctuate

range when the engine is running above low idle. If the

in or near the cold range. This indicates the engine is

gauge still registers a discharge as the engine speed is

being overcooled. In these instances the use of radiator

increased, determine the cause.

louvers is suggested.

AUTOMATIC START-STOP

fails to start, the cranking timer will time out and lock the

An automatic start-stop system ensures that power is

start circuit open, preventing the batteries from being

supplied to a load when the normal power source is

discharged.

interrupted. The cranking panel is the heart of the system

and consists of the failure warning system and relays to

During the cranking cycle, the safety shutoffs are

start and stop the engine. When a power failure occurs the

inoperative to prevent a low oil pressure shut down. When

system senses the failure, starts the engine and transfers

oil pressure reaches a safe level the safety circuit is armed

the load to standby. When power is restored, it senses

by the arming relay, High water temperature or low oil

power restoration, transfers the load from standby and

pressure will now stop the engine and prevent major

stops the engine. The major use of automatic start-stop

damage.

systems is standby electric sets. This discussion is limited

to that application.

If an unsafe engine condition exists, a sending unit

completes the circuit to the safety relay and locking relay.

The remote contacts close when a power failure occurs

The safety relay de-energizes the fuel solenoid and stops

and completes the circuit to the cranking timer and the start

the engine. The locking relay insures that the circuit to the

slave relay. The start slave relay completes the circuit to

safety relay is complete even if the remote contacts open.

the starter motor and the engine begins cranking.

The safety circuit must be reset by moving the start

As the engine starts and increases in speed, the

selector switch to the OFF position. Before restarting any

frequency sensing relay turns off the cranking timer and

unit which has been shut down by the safety circuit, the

starts the slave relay. This disconnects the starter motor

cause must be determined and corrected.

circuit and protects the starter from overspeed damage. If

the engine

DETERMINING THE CAUSE OF SHUTDOWN

Anytime an engine is shut down by its safety circuit, the

WARNING

cause must be determined. In some cases the cause will

DO NOT remove the pressure cap of an

be obvious but often an investigation will have to be made.

overheated unit. The coolant is under

Do not put the engine back into service without determining

pressure and relieving this pressure

and correcting the cause of the shutdown.

will cause the coolant to flash into

steam.

Serious bums and engine

HIGH WATER TEMPERATURE

damage can result from the escaping

coolant. Pressure in a radiator or surge

Look for the obvious first.

tank may be reduced by pouring warm

water on the top tank to condense the

1. Check for water on the floor from spilled or leaking

steam.

coolant.

CAUTION

2. Check the water temperature gauge for accuracy.

NEVER add cold water to an overheated

engine.

3. Check air flow through the radiator.