Hitachi WJ200 Series

6−17
IGBT Test Method
The following procedure will check the inverter transistors (IGBTs) and diodes:
1. Disconnect input power to terminals [R, S, and T] and motor terminals [U, V, and
W].
2. Disconnect any wires from terminals [+] and [–] for regenerative braking.
3. Use a Digital Volt Meter (DVM) and set it for 1Ω resistance range. You can check the
status of the charging state of terminals [R, S, T, U, V, W, +, and –] of the inverter
and the probe of the DVM by measuring the charging state.
Table Legend Almost infinite resistance: ≅ ∞ Ω Almost zero resistance: ≅ 0 Ω
Part DVM Measured
Value
Part DVM Measured
Value
Part DVM Measured
Value
– + – + – +
D1 [R] [+1]
≅ ∞ Ω
D5 [S] [–]
≅ 0 Ω
TR4 [U] [–]
≅ 0 Ω
[+1] [R]
≅ 0 Ω
[–] [S]
≅ ∞ Ω
[–][U]
≅ ∞ Ω
D2 [S] [+1]
≅ ∞ Ω
D6 [T] [–]
≅ 0 Ω
TR5 [V] [–]
≅ 0 Ω
[+1] [S]
≅ 0 Ω
[–] [T]
≅ ∞ Ω
[–][V]
≅ ∞ Ω
D3 [T] [+1]
≅ ∞ Ω
TR1 [U] [+]
≅ ∞ Ω
TR6 [W] [–]
≅ 0 Ω
[+1] [T]
≅ 0 Ω
[+] [U]
≅ 0 Ω
[–][W]
≅ ∞ Ω
D4 [R] [–]
≅ 0 Ω
TR2 [V] [+]
≅ ∞ Ω
TR7 [RB] [+]
≅ ∞ Ω
[–] [R]
≅ ∞ Ω
[+] [V]
≅ 0 Ω
[+] [RB]
≅ 0 Ω
TR3 [W] [+]
≅ ∞ Ω
[RB] [–]
≅ ∞ Ω
[+] [W]
≅ 0 Ω
[–] [RB]
≅ ∞ Ω
NOTE: The resistance values for the diodes or the transistors will not be exactly the
same, but they will be close. If you find a significance difference, a problem may exist.
NOTE: Before measuring the voltage between [+] and [–] with the DC current range,
confirm that the smoothing capacitor is discharged fully, then execute the tests.
D1
[R/L1]
D2 D3
D4 D5 D6
[PD/+1] [P/+]
[RB]
TR1 TR2 TR3
TR4 TR5 TR6 TR7
[U/T1]
+
-
[N/ ]
[S/L2]
[T/L3]
[V/T2]
[W/T3]