Cautions For Application; Motor; Comparison With Commercial Power Supply Operation; Adjusting Motor Overload Protection Level - Toshiba TOSVERT VF-AS3 Instruction Manual

2. 4

Cautions for application

This section introduces cautions for use of the motor and inverter, influence of leakage current on periph-
eral devices, and measures against it.
2. 4. 1

Motor

• Use the inverter that conforms to specifications of the power supply and the three-phase motor
to be operated.
If you use the inappropriate inverter, not only will the three-phase motor not rotate correctly, but
Mandatory
it will cause serious accidents such as overheating and burning out.
action
When this inverter and the motor are used in conjunction, pay attention to the following items.

■ Comparison with commercial power supply operation

This inverter employs the sinusoidal PWM control. However, the output voltage and output current
are not perfect sine waves. They have a distorted wave that is close to sinusoidal waveform. This is
why there will be a slight increase in motor temperature, noise and vibration, compared to operation
with a commercial power supply.
■ Operation in low-speed range
When running continuously at low speed in conjunction with a general purpose motor, there may be
a decline in that motor's cooling effect. If this happens, operate with the output lower than the rated-
load.
To carry out low-speed operation continuously at the rated torque, use a constant torque motor. In
this case, select "constant torque motor" of "4" -"7" in <OLM: Motor overload protection characteris-
tic>.
For details, refer to [5. 1. 5].

■ Adjusting motor overload protection level

This inverter has a built-in electronic thermal for motor overload protection. The electronic thermal's
reference current is set to the inverter's rated current in default setting, so adjust it in linewith the
rated current of the motor being used in combination before operation.
For how to set, refer to [5. 1. 5].
■ High speed operation over 60 Hz
Operating at frequencies over 60 Hz will increase noise and vibration. This may exceed the motor's
mechanical strength limits and the bearing limits so you should inquire to the motor's manufacturer
about such operation.
■ Lubricating mechanisms
Operating an oil-lubricated reduction gear and gear motor in the low-speed range will worsen the
lubricating effect. Check with the manufacturer of the reduction gear to find out about operable gear-
ing area.
CAUTION
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2. Installation and wiring
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