If The Motor Overheats; If Peripheral Devices Like Plcs Or Others Are Influenced By The Starting Or Running Inverter; If The Earth Leakage Breaker Operates When The Inverter Is Running - Omron VARISPEED F7 User Manual

If the Motor Overheats

The following causes are possible:
The load is too large.
If the motor load is too large and the torque exceeds the motor's rated torque, the motor may overheat. Reduce
the loads by either reducing the load or increasing the acceleration/deceleration times. Also consider increas-
ing the motor size.
The ambient temperature is too high.
The motor rating is determined by a particular ambient operating temperature range. The motor will overheat
if it is run continuously at the rated torque in an environment where the maximum ambient operating tempera-
ture is exceeded. Lower the motor's ambient temperature to be within its acceptable range.
Auto-tuning has not been performed for vector control
Vector control may not perform efficiently if auto-tuning has not been performed. Perform auto-tuning, or set
the motor parameters through hand calculations. Alternatively, change the Control Mode Selection (A1-02) to
V/f Control (0 or 1).
If Peripheral Devices Like PLCs or Others are Influenced by the Starting
or Running Inverter
The following solutions are possible:
Change the Inverter's Carrier Frequency Selection (C6-02) to lower the carrier frequency. This will help to
•
reduce the amount of transistor switching noise.
Install an Input Noise Filter at the Inverter's input power terminals.
•
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Install an Output Noise Filter at the Inverter's motor terminals.
•
Use shielded motor cables or a conduit. Metal shields electrical noise.
•
Check the grounding of the Inverter and motor.
•
Separate main circuit wiring from control circuit wiring.
•

If the Earth Leakage Breaker Operates When the Inverter is Running

The Inverter's output is pulse modulated, i.e. the output voltage consists of high frequency pulses (PWM).
This high frequency signal causes a certain amount of leakage current which may cause the earth leakage
breaker to operate and cut off the power supply. Change to a ground fault interrupter with a high leakage
detection level (i.e., a sensitivity current of 200 mA or higher, with an operating time of 0.1 s or more), or one
that incorporates high frequencies countermeasures (i.e., one designed for use with Inverters). It will also help
to some extent to lower the Inverter's Carrier Frequency Selection (C6-02). In addition, remember that the
leakage current increases as the cable is lengthened.
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