Hitachi L100 NOTE:, NOTE:, Table Legend –, IGBT Test Method

6–15

L100 Inverter

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.

[+1]	[+]
D1 D2 D3	TR1	TR2	TR3

[R]	+	[U]
[S]		[V]
[T]		[W]

Troubleshooting Maintenance and

D4

D5

D6

[–]

TR4

TR5

TR6

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]

[N]

≅ 0 Ω

TR4

[U]

[–]

≅ 0 Ω

+1

[R]

≅ 0 Ω

[N]

[S]

≅ ∞ Ω

[–]

[U]

≅ ∞ Ω

D2

[S]

+1

≅ ∞ Ω

D6

[T]

[N]

≅ 0 Ω

TR5

[V]

[–]

≅ 0 Ω

+1

[S]

≅ 0 Ω

[N]

[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]

[N]

≅ 0 Ω

TR2

[V]

[+]

≅ ∞ Ω

TR7

[RB]

[+]

≅ 0 Ω

[N]

[R]

≅ ∞ Ω

[+]

[V]

≅ 0 Ω

[+]

[RB]

≅ ∞ Ω

TR3

[W]

[+]

≅ ∞ Ω

[RB]

[–]

≅ 0 Ω

[+]

[W]

≅ 0 Ω

[–]

[RB]

≅ 0 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.