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3G3JV Maintenance Operations Chapter7
• The ambient temperature is too high.
The rating of the motor is determined within a particular ambient operating temperature range.
The motor will burn out if it runs continuously at the rated torque in an environment in which the
maximum ambient operating temperature is exceeded.
Lower the ambient temperature of the motor to within the acceptable ambient operating
temperature range.
• The withstand voltage between the phases of the motor is insufficient.
When the motor is connected to the output of the Inverter, a surge will be generated between
the switching of the Inverter and the coil of the motor.
Normally, the maximum surge voltage is approximately three times the input power supply
voltage of the Inverter (i.e., approximately 600 V for 200-V models, and approximately 1,200
V for 400-V models).
Therefore, the dielectric strength of the motor to be used must be higher than the maximum
surge voltage.
7-2-7 Controller or AM Radio Receives Noise when Inverter
is Started
• Noise derives from Inverter switching.
Take the following actions to prevent noise.
• Lower the carrier frequency of the Inverter in n46.
The number of internal switching times is reduced, so noise can be reduced to some
extent.
• Install an Input Noise Filter.
Install an Input Noise Filter on the power input area of the Inverter.
• Install an Output Noise Filter.
Install an Output Noise Filter on the output area of the Inverter.
• Use metal tubing.
Electric waves can be shielded by metal. Therefore, enclose the Inverter with a metal tube.
7-2-8 Ground Fault Interrupter is Actuated when Inverter
is Started
• Leakage current flows through the Inverter.
The Inverter performs internal switching. Therefore, a leakage current flows through the
Inverter. This leakage current may actuate the ground fault interrupter, shutting the power
off.
Use a ground fault interrupter with a high leakage-current detection value (sensitivity amperage
of 200 mA or more, operating time of 0.1 s or more) or one with high-frequency
countermeasures for Inverter use.
Reducing the carrier frequency value in n46 is also
effective.
In addition, remember that a leakage current increases in proportion to the cable length.
Normally, approximately 5 mA of leakage current is generated for each meter of cable.
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