Insulation resistance tests – Generac Power Systems IM Series User Manual

Page 11

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INSULATION RESISTANCE TESTS

General

Refer to EFFECTS OF DIRT AND MOISTURE ON RV
GENERATORS (Page 5). The resistance of rotor and
stator windings should be tested periodically, using a
"Hi-Pot" resistance tester.

CAUTION!: When using the Hl-Pot (Insulation Resis
tance) tester, follow the tester manufacturer’s In
structions carefully. Improper use of the tester can
result in serious damage to the generator. Do not

apply voltage in excess to those recommended in
this Manual to Stator or Rotor windings.____________

The Hi-Pot Tester

The Hi-Pot tester shown is oniy one of many brands

available. It is equipped with an On/Off switch. Thepiiot

Lamp glows to indicate tester power is availabie. The

breakdown tamp will light to Indicate failure of the winding
being tested.

Testing Stator insuiation

6 Gain Access to Stator Leads: Remove screws that

retain the front panel to the panel housing. Remove the
generator cover. Inside the panel housing, locate the
Electronic Voltage Regulator and the 30-amp Circuit
Breaker (CB1).

C Disconnect Stator Leads: Disconnect Stator a-c
output wires 11 and 22 from the Electronic Voltage
Regulator terminals. Disconnect Stator Wire 33 from the
30-amp Breaker (CB1). Separate wires 22 and 44 at their

junction. Finally, disconnect Stator Excitation Wiriding

Wires 2 and 6 from the Electronic Voltage Regulator
terminals.

DANGER!: Follow the Instructions carefully. Wire
terminal ends must not be touching any part of the
generator when Hl-Pot voltage Is applied. Do not
exceed the recommended voltages. Apply voltage
to windings for a maximum of 1 second only.

Test All Stator Windings to Ground: Connect terminal
ends of Stator a-c output Wires 11, 22, 33, 44, 2 and 6
tightly together. Make sure no terminal end is in contact
with the generator frame. Then proceed as follows:

1 .Connect RED test lead of Hi-Pot tester to joined ter

minal ends of Wires 11,22, 33, 44, 2 and 6.

2. Connect the BLACK test lead to a dean, painted frame
ground (on generator Stator can).

3. Turn Hi-Pot tester switch OFF. Then plug tester into a

120 voits wall socket and set its Voltage Selector Switch

to 500 volts.

CAUTION!: IN STEP 4, DO NOT APPLY VOLTAGE
LONGER THAN ONE MINUTE.

4. Tum tester switch ON and check that Pilot Lamp is ON.
Then, set Voltage Selector Switch to 2000 volts. Observe
the BREAKDOWN lamp, wait one second, then turn
tester switch OFF.