1. Rectifier Module Test

a) Set the multimeter to diode test mode (ensure the test leads are plugged into the correct ports).
b) Procedure:

• Place the black lead on the DC bus positive (+) terminal, and touch the red lead to each power input terminal R, S, T in sequence. Record the three readings.
• Place the red lead on the DC bus negative (-) terminal, and touch the black lead to R, S, T in sequence. Record the three readings.
  c) Evaluation:
• All six readings should be roughly equal (around 0.4V), indicating a healthy rectifier bridge.
• If any phase reads 0 or shows a significant deviation, the corresponding rectifier module is faulty.

2. Inverter IGBT Test

Method 1: Diode Test
a) Set the multimeter to diode test mode.
b) Procedure:

• Place the black lead on the DC bus positive (+) terminal, and touch the red lead to each motor output terminal U, V, W in sequence. Record the three readings.
• Place the red lead on the DC bus negative (-) terminal, and touch the black lead to U, V, W in sequence. Record the three readings.
  c) Evaluation:
• All six readings should be roughly equal (around 0.43V), indicating healthy IGBTs.
• If any phase reads 0 or shows an excessive deviation (e.g., >0.05V), the corresponding IGBT is damaged.

Method 2: Resistance Test (Secondary Verification)
a) Set the multimeter to resistance mode (use a high range, e.g., 2MΩ or above).
b) Procedure:

• Place the black lead on the DC bus positive (+) terminal, and touch the red lead to U, V, W in sequence. Record the three readings.
• Place the red lead on the DC bus negative (-) terminal, and touch the black lead to U, V, W in sequence. Record the three readings.
  c) Evaluation:
• All six readings should be roughly equal (around 4.2MΩ), indicating healthy IGBTs.
• If any phase reads 0 or shows a significant deviation, the corresponding IGBT is damaged.