Generac Power Systems 20 kW LP Rotor Insulation Resistance Test 10 kW, Cleaning The Generator

Section 1.5

Testing, cleaning and drying

Part 1

General information

Testing All Stator Windings To Ground:

1.Disconnect Stator Output Leads 11 and 44 from the generator main line circuit breaker.

2.Disconnect Stator Output Leads 2 and 6 from the capacitor located on the end of the stator assembly.

3.Remove Stator Output Leads 22 and 33 from the neutral connection and separate the two leads.

4.Connect the terminal ends of Wires 11, 22, 33, and 44 together. Make sure the wire ends are not touching any part of the generator frame or any terminal.

5.Connect the red test probe of the Hi-Pot tester to the joined terminal ends of Stator Leads 11, 22, 33, and 44. Connect the black tester lead to a clean frame ground on the stator can. With tester leads connected in this manner, proceed as follows:

a.Turn the Hi-Pot tester switch OFF.

b.Plug the tester cord into a 120 volt AC wall socket and set its voltage selector switch to “1500 volts”.

c.Turn the tester switch ON and observe the breakdown lamp on tester. DO NOT APPLY VOLTAGE LONGER THAN 1 SECOND. After one (1) second, turn the tester switch OFF.

6.Connect the terminal ends of Wires 2 and 6 together. Make sure the wire ends are not touching any part of the generator frame or any terminal.

7.Repeat Step 5.

If the breakdown lamp came on during the one (1) second test, cleaning and drying of the rotor may be necessary. After cleaning and drying, repeat the insu- lation breakdown test. If breakdown lamp comes on during the second test, replace the rotor assembly.

Rotor Insulation Resistance Test

(8-10 kW)

No test available.

Rotor Insulation Resistance Test

(12-20 kW)

Before attempting to test rotor insulation, the brush holder must be completely removed. The rotor must be completely isolated from other components before starting the test. Attach all leads of all stator windings to ground.

1.Connect the red tester lead to the positive (+) slip ring (nearest the rotor bearing).

2.Connect the black tester probe to a clean frame ground, such as a clean metal part of the rotor shaft.

3.Turn the tester switch OFF.

4.Plug the tester into a 120 volts AC wall socket and set the voltage switch to “1500 volts”.

5.Turn the tester switch “On” and make sure the pilot light has turned on.

6.Observe the breakdown lamp, then turn the tester switch

OFF. DO NOT APPLY VOLTAGE LONGER THAN ONE

(1) SECOND.

If the breakdown lamp came on during the one (1) second test, cleaning and drying of the rotor may be necessary. After cleaning and drying, repeat the insu- lation breakdown test. If breakdown lamp comes on during the second test, replace the rotor assembly.

POSITIVE (+)

TEST LEAD

Figure 9. Testing Rotor Insulation (12-20kW)

Cleaning The Generator

Caked or greasy dirt may be loosened with a soft brush or a damp cloth. A vacuum system may be used to clean up loosened dirt. Dust and dirt may also be removed using dry, low-pressure air (25 psi maximum).

*CAUTION: Do not use sprayed water to clean the generator. Some of the water will be retained on generator windings and terminals, and may cause very serious problems.

Drying The Generator

To dry a generator, proceed as follows:

1.Open the generator main circuit breaker. NO ELECTRICAL LOADS MUST BE APPLIED TO THE GENERATOR WHILE DRYING.

2.Disconnect all Wires 6 from the voltage regulator.

3.Provide an external source to blow warm, dry air through the generator interior (around the rotor and stator wind- ings. DO NOT EXCEED 185° F. (85° C.).

4.Start the generator and let it run for 2 or 3 hours.

5.Shut the generator down and repeat the stator and rotor insulation resistance tests.

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