5- 4

5.5 How to check inverter & converter portion
Inverter and converter module can be checked by using a tester.

(Preparation)

(1)Disconnect all the connected wires and devices to the power terminals (R, S, T, U, V, W, P and RB).
(2)Tester is to be set as 1ohm range.

(How to check)

Check the ON condition of each point shown below.
(note 1) Be sure to discharge DC bus voltage beforehand, which should be checked by DC bus voltage.
(note 2) Normally, the resistance shows ∞ in case of OFF mode.
In some cases resistance does not show ∞ due to the capacitance of DC bus capacitors.
Resistance shows 3ohm ~ 50ohm (depends on the tester voltage) in case of ON mode.
Resistance values may not be completely the same due to the electrical device (IGBT chip, diode chip…) difference.
But we can regard the result is okay if all the data are nearly the same.
Tester polarity
(Red)
(
Blk)
Measure
ment
RPD OFF
D1 PD RON
SPD OFF
D2 PD SON
TPD OFF
D3 PD TON
R N ON
D4 N R OFF
SNON
D5 NSOFF
TNON
Converter
D6 NTOFF
UPOFF
TR1 PUON
V P OFF
TR3 P V ON
WPOFF
TR5 PWON
U N ON
TR4 N U OFF
VNON
TR6 NVOFF
WNON
Inverter
TR2 NWOFF
RB POFF
PRB ON
RB NOFF
BRD
TR7
NRB OFF
A K OFF
AGOFF
K A OFF
KGON
GAOFF
Thyristor
THY
GKON
ON; Low resistance
OFF; High resistance
Converter Inverter
PD P
D1 D2 D3
D4
D5 D6
R
S
T
TR7
C+
RB
U
V
W
TR4 TR6 TR2
TR1 TR3 TR5
NBRD
G
K
A
Thyristor portion
THY