Generac Power Systems NP-40G - Manual (Page 21)

Section 1.5- COMPONENTS TESTING
Introduction
Problems that occur In the computer-controlled
RV generator generally Involve the following sys­
tems or components:
1. The engine.
2. The Speed Control System.
3. The AC Generator.
4. The Genistor.
5. Battery Charge Circuit.
6{ CCG Circuit Board.
7. Wiring Harness and Front Panel.
This Section will discuss test procedures for the
following components. Also see Part 8 of this
Manual, “TROUBLESHOOTING".
1. The AC Generator (Stator).
2. The Genistor.
3. Battery Charge Circuit.
4. CCG Circuit Board.
A short circuit between windings.
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:
A. If the engine starts but the Stepper Motor does
not move, and shutdown occurs after several sec­
onds, look for the following:
1. Broken or shorted Power Supply winding
(Wires PS1 and PS2).
2. Broken or shorted Timing winding (Wires TIM1
and TIM2).
NOTE: If the Power Supply windina Is shorted to
ground, a burned area on the CCG circuit board
mircult board ground track) may be visible. If the
Timing winding Is shorted to ground, the circuit will
probably be damaged but bum-up may not be vls-
B. If the engine shuts down but speed did NOT
exceed 4500 rpm, look for the following:
1. One of the main windings (Power Phase 1 or
2) is open.
2. One of the main windings (Power Phase 1 or
2) is shorted to ground.
TESTING THE STATOR WITH A VOM:
A Volt-Ohm-Milliammeter (VOM) can be used to
test the Stator windings for tne following faults:
□ An open circuit condition.
□ A "short-to-ground“ condition.
□
□
NOTE: The resistance of Stator windings Is very
low. Some meters will not read such alow resis­
tance and will simply Indicate “continuity". Recom­
mended Is a high quality, digital type meter capable
of reading very low resistances.
TESTING POWER PHASE WINDINGS:
A. Refer to Figures 1 and 2. To test the Power
Phase windings for an open circuit condition, pro­
ceed as follows:
1. Disconnect the following wires:
a. Lead “AC1" (Gray) at the Genistor.
b. Lead “AC2” (Yellow) at the Genistor.
c. Lead “SL1" (Orange) at the Genistor.
d. Lead “SL2" (Brown) at the Genistor.
e. Lead No. 11 (Blue) at the Main Circuit Breaker
(CB1).
2. Make sure all of the disconnected leads are
isolated from each other and are not touching the
frame during the test.
3. Set a VOM to its "Rxl" scale and zero the
meter.
4. Connect one VOM test lead to Lead No. 11
K . Then, connect the remaining test lead as
s:
a. To Lead AC1 and note the resistance reading,
b. To Lead AC2 and note the resistance reading,
c. To lead SL1 and note the resistance reading,
d. To lead SL2 and note the resistance reading.
NOMINAL RESISTANCE- POWER PHASE WINDINGS
0.30 to 0.42 ohm
Figure 1. Schematic- Stator Windings
POWER
PHASE 1
POWER
PHASE 2
nSGfiSIPr
PS1 c
POWER
SUPPLY
TIMING
TIMI T1M2
BATTERY
CHARGE
Page 1.5-1