Checking The Inverter And Converter Semiconductor Devices - Mitsubishi Electric 800 Series Hardware Instruction Manual

NOTE
• Continuous use of a leaked, deformed, or degraded smoothing aluminum electrolytic capacitor (as shown in the table above)
may lead to a burst, breakage, or fire. Replace such capacitor without delay.
5.1.4 Checking the inverter and converter
semiconductor devices
 Preparation
• Disconnect the external power supply cables (R/L1, S/L2, T/L3) and motor cables (U, V, W). (Measurement can be made
without disconnecting the cables connecting the inverter and the converter unit (FR-CC2).)
• Prepare a continuity 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.
NOTE
• Before measurement, check that the smoothing capacitor is discharged.
• At the time of electric discontinuity, the measured value is almost ∞. When there is an instantaneous 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. When all measured values are almost the same (although values may not be constant depending on the
tester type), it shows that there are no electrical paths with problems.
 Semiconductor device numbers and terminals to be checked
D1
Converter unit D2
D3
TR1
Inverter TR3
TR5
(Assuming that an analog meter is used.)
Converter unit
D1 D2
R/L1
S/L2
T/L3
D4 D5
106
5. PRECAUTIONS FOR MAINTENANCE AND INSPECTION
5.1 Inspection item
Tester
polarity
Continuity
R/L1 P/+ No
D4
P/+ R/L1 Yes
S/L2 P/+ No
D5
P/+ S/L2 Yes
T/L3 P/+ No
D6
P/+ T/L3 Yes
U P/+ No
TR4
P/+ U Yes
V P/+ No
TR6
P/+ V Yes
W P/+ No
TR2
P/+ W Yes
P/+ P/+
TR1
D3
C C
D6
TR4
N/- N/-
Tester
polarity
Continuity
R/L1 N/- Yes
N/- R/L1 No
S/L2 N/- Yes
N/- S/L2 No
T/L3 N/- Yes
N/- T/L3 No
U N/- Yes
N/- U No
V N/- Yes
N/- V No
W N/- Yes
N/- W No
Inverter
TR3 TR5
U
V
W
TR6 TR2