Hitachi CONVENTION 14 - Manual (Page 234)

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 1 Ÿ 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: # ’ Ÿ Almost zero resistance: # 0 Ÿ
DVM DVM DVM Part
+ –
Measured
Value
Part
+ –
Measured
Value
Part
+ –
Measured
Value
[R] [+1] # ’ Ÿ [S] [–] # 0 Ÿ [W] [+] # ’ Ÿ D1
[+1] [R] # 0 Ÿ
D5
[–] [S] # ’ Ÿ
TR3
[+] [W] # 0 Ÿ
[S] [+1] # ’ Ÿ [T] [–] # 0 Ÿ [U] [–] # 0 Ÿ D2
[+1] [S] # 0 Ÿ
D6
[–] [T] # ’ Ÿ
TR4
[–] [U] # ’ Ÿ
[T] [+1] # ’ Ÿ [U] [+] # ’ Ÿ [V] [–] # 0 Ÿ D3
[+1] [T] # 0 Ÿ
TR1
[+] [U] # 0 Ÿ
TR5
[–] [V] # ’ Ÿ
[R] [–] # 0 Ÿ [V] [+] # ’ Ÿ [W] [–] # 0 Ÿ D4
[–] [R] # ’ Ÿ
TR2
[+] [V] # 0 Ÿ
TR6
[–] [W] # ’ Ÿ
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.
6 15
T
roubleshooting and
Maintenanc
e
6 15
T
roubleshooting and
Maintenance