Webasto BCT010300C Repair Manual download pdf (Page 34)

Troubleshooting – Refrigerant Compressor

Webasto Product N.A., Inc. 32 www.techwebasto.com

™

6.4.1 Checking for a Ground Fault (a Short to

Ground)

Step 1: Disconnect Power

Disconnect all electrical power supplies to the system,

making sure that all power legs are open.

(NOTE: The system may have more than one power

supply.)

Step 2: Check for a Ground Fault

Remove the protective terminal cover. If there is any

evidence of overheating at any lead, this is a good

indication that a compressor motor problem exists. At

this time, do not replace or attach leads or connectors

that have been damaged by overheating.

Disconnect leads and/or remove all components (such as

relays and capacitors) from the terminal pins.

If a capacitor is present, using a 20,000

ohm resistor, discharge it before

removing it from the system to avoid

damage to measuring devices and risk of

electric shock.

When removing a current type relay, keep it upright.

Check the compressor for a ground fault using either a

megohmmeter (“megger”) or a Hi-Potential Ground

Tester (“Hi-Pot”).

To reduce the risk of electrocution,

always follow the manufacturers’

procedures and safety rules when using

these devices.

Connect one lead of either the megger or Hi-Pot to the

copper suction line. Connect the other lead to one of

the terminal pins.

Repeat this procedure for the two remaining terminal

pins. If the instrument indicates any resistance less that 2

megohms between any pin and the housing (copper

suction line), a ground fault exists.

To avoid electric shock, electrocution, and

terminal venting with ignition do not

energize a compressor that has a ground

fault.

If a ground fault exists, keep the power off and replace

the compressor. See “System Cleanup and Compressor

Replacement After Compressor Failure” starting on

page 36.

If the compressor is not replaced immediately, mark and

red tag the compressor to indicate there is a ground

fault. Do not reconnect the power leads. Tape and

insulate each power lead separately.

If a ground fault does not exist, leave the power off and

all external components disconnected from the terminal

pins. Check for continuity and proper resistance using

the procedure in Section 6.4.2.

CAUTION

WARNING

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Webasto BCT010300C Repair Manual Page 34

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