Pillartech
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Testing an IGBT

1. Check For Shorted IGBT

Using a digital ohmmeter on the diode scale:

  1. Measure resistance between C2/E1 and E2.
  2. Measure resistance between C2/E1 and C1.

If you measure a short (0 ohms) in step 1a. or 1b., the IGBT is not usable.

2. Turn on Q1, Q2

Using a digital ohmmeter on the diode scale:

  1. Touch the + (red) meter lead to G1 and the - (black) to E1.
  2. Touch the + (red) meter lead to G2 and the - (black) to E2.
  3. Measure resistance between C1 and C2/E1. Should read a low resistance (about a diode drop). Reverse meter leads, reading should be the same.
  4. Measure resistance between E2 and C2/E1. Should read a low resistance (about a diode drop). Reverse meter leads, reading should be the same.
3. Turn off Q1, Q2

Using a ohmmeter on the diode scale:

  1. Touch the + (red) meter lead to E1 and the - (black) to G1.
  2. Touch the + (red) meter lead to E2 and the - (black) to G2.
  3. Measure resistance between C2/E1 (+) and C1 (-). Should read a low resistance (same as in step 2c.). Reverse meter leads. Read infinite resistance.
  4. Measure resistance between C2/E1 (-) and E2 (+). Should read a low resistance (same as in step 2d.). Reverse meter leads. Read infinite resistance.

Note: Some digital ohmmeters do not have enough power to turn on an IGBT. A 9 volt battery may be used instead.