6. TROUBLESHOOTING
6-12
NOTICE
Insulation resistance test using megger
Where possible, do not conduct an insulation resistance test using a megger since
an insulation test has been done before shipment from the factory. When it is
inevitable to make an insulation resistance test using a megger, disconnect all
cables from the control circuit to prevent a test voltage from leaking into the control
circuit. The drive unit will fail if the test voltage is applied to the control circuit.
R
S
T
U
V
W
M
Motor
Power supply
500VDC
megger
Drive unit
Earth terminal
Pressure test
Do not conduct a pressure test. A pressure test can deteriorate the semiconductor
parts in the drive unit.
6.4.2 Wear parts
The replacement lives of the parts are as indicated below. Since the lives vary with the operating
environment and/or usage, you must replace the parts if you have found any fault during periodic
inspection or the like.
Part Name
Standard
Replacement
Intervals
Method Remarks
Cooling fan 2 to 3 years Change (as required)
The bearing life of the cooling fan is 10,000
to 35,000 hours. For continuous operation,
therefore, normally replace the fan every 2
to 3 years as a guideline.
Main circuit
smoothing
capacitor
10 years Change (as required)
On-board
smoothing
capacitor
10 years Change (as required)
The life greatly depends on the ambient
temperature and operation specifications of
the drive unit. When continuous operation is
performed in normal air-conditioned
environment, the life is approximately 10
years. The life halves for each 10
°
C rise in
ambient temperature.
The capacitor deteriorates rapidly after the
given period has elapsed, causing the motor
to run unstably or activating the overcurrent
protective function.