Generac Power Systems 941-2 Service Manual page 23

INTRODUCTION
Problems that occur In the computer-controlled RV
generator generally involve the following systems or
components:
1. The engine.
2. The Speed Control System.
3. The AC Generator.
4. Battery Charge Circuit.
5. A6060 Circuit Board.
6. Wiring Harness and Front Panel.
This Section will discuss test procedures for the fol-
lowing components. Also see Part 8 of this Manual,
"TROUBLESHOOTING".
1. The AC Generator (Stator).
2. Battery Charge Circuit.
3. A6060 Circuit Board.
STATOR ASSEMBLY
GENERAL:
For additional information on the Stator, refer to the
following:
1. "Stator Assembly" on Page 1.2-2.
2. Section 1.4, "INSULATION RESISTANCE".
SYMPTOMS OF STATOR FAILURE:
If the engine starts but the Stepper Motor does not
move, and shutdown occurs after several seconds,
look for broken or shorted timing windings (Wires
TIM1 and TIM2).
TESTING THE STATOR WITH A VOM:
A Volt-Ohm-Milliammeter (VOM) can be used to test
the Stator windings for the following faults:
• An open circuit condition.
• A "short-to-ground" condition.
• A short circuit between windings.
NOTE: The resistance of Stator windings Is very
low. Some meters will not read such a low resis-
tance and will simply Indicate "continuity"
Recommended Is a high quality, digital type meter
capable of reading very low resistances.
TESTING POWER PHASE WINDINGS:
A. Refer to Figures 1 and 2 on this page and the next. To test the
Power Phase windings for an open circuit condition, proceed
as follows:
COMPONENTS TESTING
1. Disconnect the following wires:
a. Lead "AC1" (Grey) at CB1A.
b. Lead "AC2" (Yellow) at BR1.
c. Lead "SL1 " (Orange) at CB1B.
d. Lead "SL2" (Brown) at BR3.
2. Make sure all of the disconnected leads are iso-
lated from each other and are not touching the
frame during the test.
3. Set a VOM to its "Rx1" scale and zero the meter.
4. Connect one test lead to AC1 and one test lead
to AC2. Note the resistance reading.
5. Connect one test lead to SL1 and one test lead
to SL2. Note the resistance reading.
NOMINAL RESISTANCE- POWER PHASE WINDINGS
0.414 to 0.465 ohm
Figure 1. Stator Leads
B. To test the Power Phase windings for a "short-to-ground" con-
dition, proceed as follows:
1. Make sure all leads are Isolated from each other
and are not touching the frame.
2. Set a VOM to its "Rx10,000" or "Rx1K" scale
and zero the meter.
3. Connect one VOM test lead to the terminal end
of Stator Lead "AC1", the other test lead to a
clean frame ground on the Stator.
a. The meter should read "infinity".
b. Any reading other than "infinity" indicates a
"short-to-ground" condition.
c. Repeat #3 again using Stator Lead "SL1."
Section 1.5
Page 1.5-1