Omron MX2 Series User Manual page 546

11 Maintenance and Inspection
Test Method
Measure the resistance at the inverter main circuit terminals block R/L1, S/L2, T/L3, U/T1, V/T2, W/T3,
RB, P/+2, and N/− by alternating the polarity of the tester to judge the conduction state.
• Before starting the test, measure the voltage between P/+2 and N/− in the DC voltage range to check
that the smoothing capacitor is sufficiently discharged.
• The tester will show nearly infinite resistance in a no-conduction state. (With conduction, the tester
will show a resistance from a few Ω to several tens of Ω.)
However, it may not show infinite resistance if a momentary conduction is detected due to the influ-
ence of the smoothing capacitor.
The inverter or converter unit is in good condition if the measured value for each item in the following
table is nearly equal, although it does not match exactly because of the element type, tester type, and
so on.
D1
D2
D3
Converter
unit
D4
D5
D6
Converter unit
D1 D2 D3
R/L1
S/L2
T/L3
D4 D5 D6
11 - 8
Tester polarity Measurement
+ (Red) − (Black)
result
+1
R/L1 No conduction
+1
R/L1 Conduction
+1
S/L2 No conduction
+1
S/L2 Conduction
+1
T/L3 No conduction
+1
T/L3 Conduction
R/L1 N/− Conduction
N/− R/L1 No conduction
S/L2 N/− Conduction
N/− S/L2 No conduction
T/L3 N/− Conduction
N/− T/L3 No conduction
Regenerative braking unit
+1
RB
P/+2
TR1
C
TR7
TR4
N/−
TR1
TR2
TR3
Inverter
unit
TR4
TR5
TR6
Regenerative
TR7
braking unit
Inverter unit
TR2 TR3
U/T1
V/T2
W/T3
TR5 TR6
Multi-function Compact Inverter 3G3MX2-V1 User's Manual (I585-E1)
Tester polarity Measurement
+ (Red) − (Black)
result
U/T1 P/+2 No conduction
P/+2 U/T1 Conduction
V/T2 P/+2 No conduction
P/+2 V/T2 Conduction
W/T3 P/+2 No conduction
P/+2 W/T3 Conduction
U/T1 N/− Conduction
N/− U/T1 No conduction
V/T2 N/− Conduction
N/− V/T2 No conduction
W/T3 N/− Conduction
N/− W/T3 No conduction
RB P/+2 No conduction
P/+2 RB Conduction
RB N/− No conduction
N/− RB No conduction