Igbt Test Method - Hitachi L200 Series Service Manual

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 [RB] 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, RB, +, and –] of the inverter
and the probe of the DVM by measuring the charging state.
D1
[R]
[S]
[T]
D4
Table Legend – Almost infinite resistance: ≅ ∞ Ω Almost zero resistance: ≅ 0 Ω
DVM
Part
+
D1 [R]
+1
D2 [S]
+1
D3 [T]
+1
D4 [R]
[N]
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.
[+1] [+] [RB]
D2 D3
+
TR7
D5 D6
[–]
Measured
Part
Value
–
≅ ∞ Ω
+1 D5
≅ 0 Ω
[R]
≅ ∞ Ω
+1 D6
≅ 0 Ω
[S]
≅ ∞ Ω
+1 TR1
≅ 0 Ω
[T]
≅ 0 Ω
[N] TR2
≅ ∞ Ω
[R]
TR3 [W]
TR1 TR2
TR4 TR5
DVM
Measured
Part
Value
+ –
≅ 0 Ω
[S] [N] TR4
≅ ∞ Ω
[N] [S]
≅ 0 Ω
[T] [N] TR5
≅ ∞ Ω
[N] [T]
≅ ∞ Ω
[U] [+] TR6
≅ 0 Ω
[+] [U]
≅ ∞ Ω
[V] [+] TR7
≅ 0 Ω
[+] [V]
≅ ∞ Ω
[+]
≅ 0 Ω
[+] [W]
6–15
SJ200 Inverter
TR3
[U]
[V]
[W]
TR6
DVM
Measured
Value
+ –
≅ 0 Ω
[U] [–]
≅ ∞ Ω
[–] [U]
≅ 0 Ω
[V] [–]
≅ ∞ Ω
[–] [V]
≅ 0 Ω
[W] [–]
≅ ∞ Ω
[–] [W]
≅ 0 Ω
[RB] [+]
≅ ∞ Ω
[+] [RB]
≅ 0 Ω
[RB] [–]
≅ 0 Ω
[–] [RB]