TECO-Westinghouse PA7300 Series, Инструкция по установке и эксплуатации

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App-13
PA 7300 APPENDIX
F. NOTES ON APPLICATION OF MOTORS
Motor Application Notes for Standard Motors
A standard motor driven by the AC Drive generates slightly less
power than it does when it is driven with commercial power supply.
Also, the cooling effect deteriorates in low speed range so that the
motor temperature rise increases. Reduce load torque in the low
speed range. Allowable load characteristics of the standard motor
are shown in the figure. If 100% continuous torque is required in
the low speed range, use an AC Drive duty motor.
• High speed operation
When the motor is used above 60Hz, motor mechanical design should be verified. Contact
your motor manufacturer.
• Torque characteristics
Motor torque characteristics vary when the motor is driven by an AC Drive instead of commercial power
supply. Check the load torque characteristics of the machine to be connected.
•
Vibrations
Because of the high carrier modulation technique for PWM control, the PA7300 series reduces motor
vibration to a level equal to running with a commercial power supply. Larger vibrations may occur off of the
following conditions:
(1) Response at resonant frequency of the mechanical system. Special care is required if a machine which has
previously been driven at a constant speed, is to be driven at varying speeds. Installation of anti-vibration
rubber padding under the motor base and frequency jump control are recommended.
(2) Rotator residual imbalance special care is required for operation at 60Hz or higher frequencies.
•
Noise
AC Drive operation is as quiet as operation with a commercial power supply. At above rated speed(60Hz),
noise may increase by motor cooling fan.
Application to Special Purpose Motors
Motors with Brakes Use brake-equipped motors with an independent power supply. Connect the brake power supply to the AC Drive primary
side. When the brake Operates (the motor stops) it turns the AC Drive output OFF. Some types of brakes may make
abnormal sounds in low speed range.
Pole Change Motors Select the AC Drive with a capacity exceeding the rated current of each pole. Pole change should be made only after
the motor stops. If a pole is changed while the motor is rotating, the regenerative overvoltage or overcurrent protection
circuit is activated and the motor coasts to a stop.
Submersible Motors Since the rated current of underwater motors is large compared with general purpose motors, select an AC Drive with a
larger capacity. If the wire length between the AC Drive and the motor is large, use cables with sufficiently large diameter.
Explosion-proof Motors Explosion-proof motors which are applied to AC Drives must be currently approved as explosion-proof equipment.
The AC Drive is not explosion-proof and should not be located where explosive gases exist.
Geared Motors Lubrication method and continuous rotation limit differ with manufacturers. When oil lubrication is employed, continuous
operation only in low speed range may cause burnout. Before operating the motor at more than 60Hz, you should consult
the motor manufacturer.
Single-phase Motors Single-phase motors are not suitable for variable speed operation with an AC Drive. If the AC Drive is applied to a motor
using a capacitor stack, a high harmonic current flows and the capacitor may be damaged. For split-phase start motors
and repulsion start motors, the internal centrifugal switch will not be actuated and the starting coil may be burned out.
Therefore, only use 3-phase motors.
• Power Transmission Mechanism (Gear Reduction, Belt, Chain, etc.)
When gear boxes and change/reduction gears lubricated with oil are used in power transmission systems,
(Continuous low speed operation decreases the oil lubrication function). Also, operation at more than 60Hz
may result in noise, reduced life, etc.
Allowable Load Characteristics
of the Standard Motor
FREQUENCY (Hz)
3 6 20 60
100
82
70
60
50
0
Torque
(%)
25% ED(OR 15MIN)
40% ED(OR 20MIN)
60% ED(OR 40MIN)