30 • Chapter 4 - Installation Guidelines ARTDriveG Instruction manual
4.4 Motors and Encoder
The AGy Drives are designed for open-loop and closed-loop operation of standard three-phase induction AC motors.
4.4.1. AC Induction Motors
FOR BEST RESULTS:
Select a inverter duty single cage induction motor with a minimum slip of 3-5%.
a) Minumum motor size: motor amps no less than 30% of drive rated amps at 400 VAC continuous rating
b) General purpose motors can be used but require additional AC output chokes
c) Inverter duty motors are desirable and do not require output chokes
The electrical and mechanical data of standard three-phase motors refers to a particular operating range. The following
points should be noted when these motors are connected to an AC Drive:
Is it possible to use standard induction motors?
With the AGy Drives it is possible to use standard induction motors. Some features of the motor have a great influence on
the obtained performances. Notice also what is stated in section 3.3.4, “AC Output”, about the voltages and the motor
power.
Star or delta connection?
Motors can be connected in both star or delta connections. Experience has shown that star connected motors have better
control properties, so star connections are preferred.
Cooling
The cooling of three-phase motors is normally implemented by means of a fan that is mounted on the motor shaft. Remember
that the output of the fan is reduced when the motor is running at lower speeds, which in certain circumstances may mean that
the cooling is insufficient for the motor. Check with the motor manufacturer whether an external fan is required and the motor
speed range in the application concerned.
Operation above the rated speed
Due to the mechanical factors involved (bearings, unbalance of rotor) and due to the increased iron losses, consult the manufacturer
of the motor if this is operated above the rated speed .
What motor data is required for connecting the frequency inverter?
Nameplate specifications
- Motor rated voltage
- Motor rated current
- Motor rated frequency
- Motor rated speed
- Power factor
- Pole pairs
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