Checking The Inverter And Converter Modules - Mitsubishi Electric FR-A820-00046 Instruction Manual

Inspection item
7.1.4

Checking the inverter and converter modules

Preparation
● Disconnect the external power supply cables (R/L1, S/L2, T/L3) and motor cables (U, V, W).
● Prepare a tester. (For the resistance measurement, use the 100 Ω range.)
Checking method
Change the polarity of the tester alternately at the inverter terminals R/L1, S/L2, T/L3, U, V, W, P/+, and
N/- and check the electric continuity.
NOTES Before measurement, check that the smoothing capacitor is discharged.
At the time of electric discontinuity, the measured value is almost ∞. When there is an instantane-
ous electric continuity, due to the smoothing capacitor, the tester may not indicate ∞. At the time
of electric continuity, the measured value is several Ω to several tens of Ω. If all measured values
are almost the same, although these values are not constant depending on the module type and
tester type, the modules are without fault.
Module device numbers and terminals to be checked
Converter module
Tab. 7-2:
(Assumes the use of an analog meter.)
7 - 4
Inverter module
Tester polarity
R/L1 P/+
D1
P/+ R/L1
S/L2 P/+
D2
P/+ S/L2
T/L3 P/+
D3
P/+ T/L3
U P/+
TR1
P/+ U
V P/+
TR3
P/+ V
W P/+
TR5
P/+ W
Continuity check of the modules
Precautions for maintenance and inspection
Fig. 7-1:
Module device numbers and terminals to be
checked
Result
Discontinuity
D4
Continuity
Discontinuity
D5
Continuity
Discontinuity
D6
Continuity
Discontinuity
TR4
Continuity
Discontinuity
TR6
Continuity
Discontinuity
TR2
Continuity
Tester polarity
Result
R/L1 N/– Continuity
N/– R/L1 Discontinuity
S/L2 N/– Continuity
N/– S/L2 Discontinuity
T/L3 N/– Continuity
N/– T/L3 Discontinuity
U N/– Continuity
N/– U Discontinuity
V N/– Continuity
N/– V Discontinuity
W N/– Continuity
N/– W Discontinuity
I001305E