Precautions For Pm Motors; Precautions For Specialized Motors - YASKAWA GA80U4720ABM Manual

Use Closed Loop Vector Control when these applications have subsynchronous resonance problems.
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Audible Noise
The audible noise of the motor changes when the carrier frequency setting changes. When you use a high carrier
frequency, audible noise from the motor is equivalent to the motor noise generated when you operate from line power.
If you operate at speeds that are more than the rated rotation speed, the unwanted motor noise increases.
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Precautions for PM Motors

• Contact Yaskawa or your nearest sales representative to use a non-Yaskawa PM motor.
• You cannot operate a PM motor from a commercial power supply. If you must operate from a commercial power
supply, use an induction motor.
• You cannot operate more than one PM motor from one drive. Use an induction motor and a variable-speed control
drive.
• In Open Loop Vector Control for PM motor (OLV/PM), the motor can operate in the reverse direction for 1/2 turn
(electrical angle) at start up.
• The quantity of generated starting torque changes when the control method and motor type change. Verify the
starting torque, permitted load characteristics, impact load tolerance, and speed control range before you set up the
motor with the drive. Contact Yaskawa or your nearest sales representative to use a motor that does not meet these
specifications.
• In OLV/PM control, braking torque is always 125% or less when operating between 20% and 100% speed. A
braking resistor unit will not change the value. Braking torque is 50% or less when operating at 20% speed or less.
• In OLV/PM control, the allowable load inertia moment is approximately 50 times higher than the motor inertia
moment. Use Closed Loop Vector Control for PM motors for applications with a larger inertia moment.
• When you use a holding brake in OLV/PM control, release the brake before you start the motor. Failure to set the
correct timing can cause a decrease in speed. Do not use these configurations in applications with heavy loads, for
example conveyors or elevators.
• To restart a coasting motor that is rotating faster than 200 Hz in V/f Control, first use the Short Circuit Braking
function to stop the motor. A special braking resistor unit is necessary for Short Circuit Braking. Contact Yaskawa
or your nearest sales representative for more information.
To restart a coasting motor that is rotating slower than 200 Hz, use the Speed Search function.
If the motor cable is long, use Short Circuit Braking to stop the motor.
Note:
The Short Circuit Braking function uses the drive to forcefully cause a short across the motor wires to stop the motor before it has time to
coast to a stop.
• You can also use EZ Open Loop Vector Control (EZOLV) to operate synchronous reluctance motors (SynRM).
Contact Yaskawa or your nearest sales representative for more information.
• After you replace a failed PM motor encoder, make sure that the motor can rotate and do Z Pulse Offset Tuning or
PM Rotational Auto-Tuning.
• If oC [Overcurrent], STPo [Motor Step-Out Detected], or LSo [Low Speed Motor Step-Out] occur during restart,
retry Speed Search and use the Short Circuit Braking function when starting to adjust the motor.
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Precautions for Specialized Motors

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Pole Change Motors
The rated current of pole change motors is different than standard motors. Check the maximum current of the motor
before you select a drive. Always stop the motor before you switch between the number of motor poles. If you change
the number of poles while the motor is rotating, the overvoltage from regeneration or the overcurrent protection
circuitry will make the motor coast to stop.
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Submersible Motors
The rated current of a submersible motor is more than the rated current of a standard motor. Use a sufficiently large
motor cable that will not let voltage drop decrease the maximum torque level.
YASKAWA SIEPC71061737B GA800 Drive Technical Reference
3.18 Motor Application Precautions
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