Mitsubishi Electric FR-D720-0.2K-G, Instruction Manual

Page: 277 / 302

274
Inspection items
6.1.4 Display of the life of the drive unit parts
The self-diagnostic alarm is output when the life span of the control circuit capacitor, cooling fan and each parts of the inrush
current limit circuit is near its end. It gives an indication of replacement time.
The life alarm output can be used as a guideline for life judgement.
6.1.5 Checking the inverter and converter modules
<Preparation>
(1) Disconnect the external power supply cables (R/L1, S/L2, T/L3) and motor cables (U, V, W).
(2) Prepare a tester. (Use 100

range.)
<Checking method>
Change the polarity of the tester alternately at the drive unit terminals R/L1, S/L2, T/L3, U, V, W,
P/
+ and
N/
-, and check for
continuity.
<Module device numbers and terminals to be checked>
Parts Judgement Level
Main circuit capacitor 85% of the initial capacity
Control circuit capacitor Estimated remaining life 10%
Inrush current limit circuit
Estimated remaining life 10%
(Power ON: 100,000 times left)
Cooling fan Less than 50% of the predetermined speed
POINT
Refer to page 231 to perform the life check of the drive unit parts.
NOTE
1. Before measurement, check that the smoothing capacitor is discharged.
2. At the time of discontinuity, the measured value is almost

. When there is an instantaneous continuity, due to the
smoothing capacitor, the tester may not indicate

.

At the time of continuity, the measured value is several to
several tens-of ohms depending on the module type, circuit tester type, etc. If all measured values are almost the
same, the modules are without fault.
Tester Polarity
Measured
Value
Tester Polarity
Measured
Value
Converter modu
le
D1
R/L1 P/+ Discontinuity
D4
R/L1 N/- Continuity
P/+ R/L1 Continuity N/- R/L1 Discontinuity
D2
S/L2 P/+ Discontinuity
D5
S/L2 N/- Continuity
P/+ S/L2 Continuity N/- S/L2 Discontinuity
D3
T/L3 P/+ Discontinuity
D6
T/L3 N/- Continuity
P/+ T/L3 Continuity N/- T/L3 Discontinuity
Inverter mod
ul
e
TR1
U P/+ Discontinuity
TR4
U N/- Continuity
P/+ U Continuity N/- U Discontinuity
TR3
V P/+ Discontinuity
TR6
V N/- Continuity
P/+ V Continuity N/- V Discontinuity
TR5
W P/+ Discontinuity
TR2
W N/- Continuity
P/+ W Continuity N/- W Discontinuity
(Assumes the use of an analog meter.)
Converter module Inverter module
D1 D2 D3
D4 D5 D6
TR1 TR3 TR5
TR4 TR6 TR2
U
V
W
R/L1
S/L2
T/L3
C
P/+
N/-