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F-13

TROUBLESHOOTING & REPAIR

F-13

 

 

 

MAIN INVERTER BOARD RESISTANCE TEST (continued)

8.Check the IGBTs for “shorts”. Check each IGBT (6) from Gate to Collector. Normal resistance is approx- imately 100 ohms.

Also check each device from Gate to Emitter. Normal resistance is approximately 40 ohms.

Check each device from Emitter to Collector. Normal reading is high resistance in one polarity and a low resistance in the opposite polarity.

Note: These devices will usually fail “short”resulting in a zero or very low resistance reading. If they “open” physical damage should be evident.

FIGURE F.3 LOCATION OF IGBTS (6)

LEAD 2 (NZL)

WRK

LEAD 3 (EL)

Plug J1

IGBT’s

(6)

Harness

Plug

RIGHT SIDE OF MACHINE

GCE

PRO-CUT 25

Page 47
Image 47
Lincoln Electric SVM149-A service manual IGBT’s