Toshiba VF-SX - Manual (Page 159)

17-2
TOSHIBA
Preventative Maintenance and Periodic Inspection:
Prepare and implement an effective preventative maintenance program so that the
Toshiba Model VF-SX drive may provide years of safe, trouble-free operation.
Perform a periodic inspection once every three to six months, depending on the
status and type of each application. Before performing the inspection be sure
the drive has been disconnected from the line power, and that the "CHARGE" lamp
is turned off.
SUGGESTED MAINTENANCE PROCEDURES:
1. Check all control and power terminals to see that none of the control
wires are becoming loose at the control terminals. Tighten any loose
connections with a screwdriver if necessary.
2. Check that the terminal pressure crimp devices at the terminals are
properly aligned and not bent, deformed, or broken. Check that none of
these devices show signs of being overheated, such as discoloration or
warping.
3. Visually inspect all wiring and confirm that there is no problem with any
of the insulation.
4. Clean all dirt and dust from the drive, especially the cooling vents. Use
a vacuum cleaner. Take special care to carefully clean the printed
circuit boards of any dirt or dust. Dust on the boards causes heat build­
up and improper current paths.
5. If the drive has not been energized for several months or longer, it is
recommended to pass current through the drive for a few hours, at a low
level. If this is the case do not apply full commercial voltage onto the
drive at once. Use a variable power supply and slowly raise the voltage
to the normal line voltage.
6. When performing an insulation test, use only the main input circuit
terminal block with 500 Volt megaohmmeter. Do NOT conduct a high pot test
on any other portion of the drive, including the control terminals.
NOTE: When performing a motor insulation test, disconnect the motor
feeder cables from the load terminals so as to test only the motor
windings, and not the drive output devices.
7. Pressure resistance test.
If a pressure resistance test is carried out on the control panel, a
pressure resistance defect may be detected due to leading currents from
the barrister in the Inverter. Thus, when carrying out the pressure
resistance test, always remove the inverter first.