Utility Voltage Dropout And Engine Cranking - Guardian 4389 Repair Manual

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Table of Contents

SECTION 4.2

OPERATIONAL ANALYSIS

• After fifteen (15) seconds and when the circuit board's 15-second timer has timed out, if utility voltage is still

below 60 percent of nominal, circuit board action will energize the circuit board's crank and run relays (K1 and

K2) simultaneously.

• The crank relay (K1) will remain energized for about 15 seconds on the first crank cycle. The relay will then de-

energize for 7 seconds and will again energize. This time it will remain energized for 7 seconds. Thus, the

engine will crank cyclically for 7 second crank-rest cycles. This cyclic cranking will continue until either the

engine starts or until about ninety (90) seconds of crank-rest cycles have been used up.

• When the crank relay (K1) is energized, circuit board action delivers 12 volts DC to a starter contactor relay

(SCR), via Wire 56. When the SCR energizes, its contacts close and battery power is delivered to a starter

ELECTRONIC

C2-10

VOLTAGE

REGULATOR

162

CB2

C2-8

DIAGRAM KEY

BA - BRUSH ASSEMBLY

BCR - BATTERY CHARGE RELAY

CB1 - CIRCUIT BREAKER, MAIN OUTPUT

CB2 - CIRCUIT BREAKER, ALT. EXCITATION

CB3 - CIRCUIT BREAKER, EXTERNAL OUTLET, PUSH/PULL

D - DIODE

FS - FUEL SOLENOID

F1 - FUSE 15 AMP

F2 - FUSE 7.5 AMP

HTO - HIGH OIL TEMPERATURE SWITCH

IM1 - IGNITION MODULE, CYLINDER #1

IM2 - IGNITION MODULE, CYLINDER #2

LOP - LOW OIL PRESSURE SWITCH

SC - STARTER CONTACTOR

SCR - STARTER CONTACTOR RELAY

SP1, SP2 - SPARK PLUGS

SW1 - AUTO / OFF / MANUAL SWITCH

SW2 - SET EXERCISE SWITCH

SM - STARTER MOTOR

TX - TRANSFORMER, 16 Vac 56 VA & 16 Vac 1 VA (DUAL SEC.)

= 12 VDC ALWAYS PRESENT

= AC VOLTAGE

= GROUND FOR CONTROL PURPOSES

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