Troubleshooting Flowcharts; Introduction; Section 5: Troubleshooting Flowcharts; If Problem Involves Ac Output - Generac Power Systems 4451 & 4986 Repair Manual

section 5

tRoublesHooting FloWcHaRts

The "Flow Charts" in this section may be used in
conjunction with the "Diagnostic Tests" of Section 6.
Numbered tests in the Flow Charts correspond to
identically numbered tests of Section 6.
FREQUENCY GOOD -
VOLTAGE &
FREQUENCY BOTH
HIGH OR LOW
GO TO PROBLEM 1
(BELOW)
Problem 1 - Voltage & Frequency Are Both High or Low
TEST 5 - CHECK
STEPPER MOTOR
CONTROL
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INTROdUCTION

If Problem Involves AC Output

TEST 1 - CHECK NO
LOAD VOLTAGE &
FREQUENCY GOOD -
VOLTAGE HIGH
ZERO OR RESIDUAL
OR
VOLTAGE LOW
GO TO VOLTAGE GO TO PROBLEM 2
REGULATOR
ADJUSTMENT,
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FREQUENCY IS GOOD,
BUT NO-LOAD
VOLTAGE IS HIGH
OR VOLTAGE
Problems 1 through 5 apply to the AC generator only.
Beginning with Problem 5, the engine DC control sys-
tem is dealt with.
FREQUENCY
ZERO VOLTAGE AND
ZERO FREQUENCY
VOLTAGE
GO TO PROBLEM 2
IS LOW
NO-LOAD VOLTAGE &
FREQUENCY GOOD -
VOLTAGE/FREQUENCY
FALLS OFF UNDER LOAD
GO TO PROBLEM 3
GO TO VOLTAGE
REGULATOR
ADJUSTMENT,
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