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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

Part

DVM

Measured

Part

DVM

Measured

 

+

Value

 

+

Value

 

+

Value

D1

[R]

[+1]

∞ Ω

D5

[S]

[]

0 Ω

TR3

[W]

[+]

∞ Ω

 

[+1]

[R]

0 Ω

 

[]

[S]

∞ Ω

 

[+]

[W]

0 Ω

D2

[S]

[+1]

∞ Ω

D6

[T]

[]

0 Ω

TR4

[U]

[]

0 Ω

 

[+1]

[S]

0 Ω

 

[]

[T]

∞ Ω

 

[]

[U]

∞ Ω

D3

[T]

[+1]

∞ Ω

TR1

[U]

[+]

∞ Ω

TR5

[V]

[]

0 Ω

 

[+1]

[T]

0 Ω

 

[+]

[U]

0 Ω

 

[]

[V]

∞ Ω

D4

[R]

[]

0 Ω

TR2

[V]

[+]

∞ Ω

TR6

[W]

[]

0 Ω

 

[]

[R]

∞ Ω

 

[+]

[V]

0 Ω

 

[]

[W]

∞ 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.

Troubleshooting and Maintenance

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Hitachi X200 Series instruction manual 15, Igbt Test Method