NVF5 Series User Manual Chapter 8 Maintenance
2
．
Whether the power terminals are in poor contact, whether copper bus bar
connections are with overheating signs;
3
．
Whether the power cables, control cables are damaged, especially the casing in
contact with the metal surface is with cut marks;
4
．
Whether the insulation binders for the power cables have fallen off;
5
．
Comprehensively clean dust on the circuit board and air duct, using a vacuum
cleaner is recommended;
6
．
For inverter insulation testing,all input and output power terminals
（
R
、
S
、
T and U
、
V
、
W
）
must be connected with short wires then tested to the ground.
Testing the
insulation of the single terminal to the ground is forbidden. Otherwise, it is dangerous to
damage the inverter. Please use 500V megoh meter
；
7
．
When testing motor insulation, the input terminals U, V, W of the motor must be
removed from the inverter and tested motor separately. Otherwise, the inverter will be
damaged.
Attention
1. The voltage withstand test has been finished before leaving the
factory; the users no longer have to conduct the test again, otherwise
the improper test could damage the device.
2. Replacing the original components in the inverter with those
different models and electrical parameters may result in damage to the
inverter.
8.5 Spare Parts Replacement
Wearing parts of the inverter mainly include cooling fan and bus capacitor ; the life of
them are closely related to operational environment and maintenance. The following table
shows the general service life.
Table 8.2 Parts Service Life
Name
Service Life
Fan
(30~40) thousand hours
Bus Capacitor
(40~50) thousand hours
Relay
About 100,000 times
Users can determine the replacement period according to the running time. 1
．
Cooling
Fan
Possible damaged reason: Bearing wearing, leaf aging.
Discriminant criteria: Whether the fan blades have cracks, whether there is
abnormal vibration sound at startup.
2
．
Filtering Electrolytic Capacitor
Possible damaged reason: High ambient temperature, frequent load changing
resulting in ripple current increase, electrolyte aging.
!
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