Insulation Resistance Test Using Megger; Dielectric Strength Test - Mitsubishi Electric FR-A500L Series Instruction Manual

5.3.4 Insulation resistance test using megger

1) Before performing the insulation resistance test using a megger on the external circuit, disconnect the
cables from all terminals of the inverter so that the test voltage is not applied to the inverter.
2) For the continuity test of the control circuit, use a tester (high resistance range) and do not use the megger
or buzzer.
3) For the inverter, conduct the insulation resistance test on the main circuit only as shown below and do not
perform the test on the control circuit. (Use a 500VDC megger.)

5.3.5 Dielectric strength test

Do not conduct a dielectric strength test. The inverter's main circuit uses semiconductors, which may be
deteriorated if a pressure test is made.
Daily and Periodic Inspection
Area of
Inspection
Inspec-
Item
tion
Check ambient
Surrounding
temperature, humidity,
environment
dust, dirt, etc.
General
Check for unusual
Overall unit
vibration and noise.
Power
Check that main circuit
supply
voltage is normal.
voltage
(1) Check with megger
(2) Check for loose
General
(3) Check for
Main
(4) Clean.
circuit
(1) Check conductors
Conductors,
(2) Check cable
cables
Terminal
Check for damage.
block
Power
supply
DC500V
megger
Description
Daily
(across main circuit
terminals and
ground terminal).
screws and bolts.
overheat-ing of
each part.
for distortion.
sheaths for
breakage.
PROTECTIVE FUNCTIONS
R<L > Inverter U
1
S<L > V
2
T<L > M
3
Ground terminal
Interval
Periodic
Method
1 2
year years
(Refer to page 3)
Visual and auditory
checks.
Measure voltage
across inverter
terminals R-S-T
<L -L -L
1 2 3,
(1) Disconnect all
cables from
inverter and
measure across
terminals R, S, T,
U, V, W <L
L U, V, W>, and
3,
ground terminal
with megger.
(2) Re-tighten.
(3) Visual check.
(1), (2) Visual check.
Visual check.
35
Motor
IM
Criterion
Ambient
temperature:
10 C to +40 C,
non-freezing.
Ambient humidity:
90% or less,
non-condensing.
No fault.
Within permissible
AC voltage
fluctuation
(Refer to page 40)
>.
(1) 5M or more.
(2), (3) No fault.
, L ,
1 2
(1), (2) No fault.
No fault
Instrument
Thermometer,
hygrometer,
recorder
Tester, digital
multimeter
500VDC class
megger