Yaskawa iQpump Drive User Manual - Manual (Page 151)

6.7 Troubleshooting
YASKAWA TM.iQp.01 iQpump Drive User Manual 151
◆ If the Motor Operates at a Higher Speed than the Speed Command
Use the following information if the motor operates at a higher speed than the Speed Command.
■ A signal is being input to the Speed Command (current) terminal A2.
If a preset frequency reference is selected, the preset reference takes priority over the normal reference.
If the PI mode of operation is enabled, the iQpump drive output frequency will change to regulate the process variable to the desired
setpoint. Then, the iQpump drive speed may go to maximum.
◆ If the Motor Overheats
Take the following steps if the motor overheats.
■
The load is too high.
If the motor load is too high and the motor is used when the effective torque exceeds the motor's rated torque, the motor will overheat.
Reduce the load amount by either reducing the load or increasing the acceleration/deceleration times. Also consider increasing 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 temperature rating is exceeded. Lower the motor's ambient
temperature to within its acceptable range.
■
The withstand voltage between the motor phases is insufficient.
When the motor is connected to the iQpump drive output, voltage surges are generated by standing waves that can occur with certain
combinations of iQpump drive carrier frequency and motor cable length. Normally the maximum surge voltage is three times the iQpump
drive's input power supply voltage (i.e., 1200 VAC for a 480 VAC). Be sure to use a motor with a withstand voltage between the motor
phases that is greater than the maximum surge voltage. In particular, when using a 480 VAC iQpump drive, use an inverter-duty (NEMA
MG1, Parts 30 & 31) motor. Motor protection filter can also be an effective measure.
◆ If Peripheral Devices Like DDCs or Others are Influenced by Starting or Running
iQpump Drive
If noise is generated by iQpump drive switching, implement the following countermeasures:
1. Change the iQpump drive's carrier frequency selection (C6-02) to lower the carrier frequency. This will help to reduce the amount of
internal switching.
2. Install an Input Noise Filter at the iQpump drive's input power terminals.
3. Use metal conduit. Electric waves can be shielded by metal, so encase the iQpump drive and power wires in metal.
4. Ground the iQpump drive and motor.
5. Separate main circuit wiring from control wiring.
◆ If a “Stand-alone” Ground Fault Interrupter Operates When the iQpump Drive is Run
The iQpump drive performs internal switching, so there is a certain amount of leakage current. This may cause an external ground fault
interrupter to operate and cut off the power supply. Whenever possible, use a ground fault interrupter with a high leakage detection level
(i.e., a sensitivity current of 200 mA or greater per Unit, with an operating time of 0.1 s or more), or one that incorporates high frequency
countermeasures (i.e., one designed for use with drives). It will also help to change the iQpump drive's carrier frequency selection
(C6-02) to lower the carrier frequency. In addition, remember that the leakage current increases as the cable is lengthened.