Motor Application Precautions - YASKAWA A1000 Technical Manual

i.2 General Safety
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Motor Application Precautions

n Standard Induction Motors
Low-Speed Range
The cooling fan of a standard motor should sufficiently cool the motor at the rated speed. As the self-cooling capability of
such a motor reduces with the speed, applying full torque at low speed will possibly damage the motor. Reduce the load torque
as the motor slows to prevent motor damage from overheat.
standard motor. Use a motor designed specifically for operation with a drive when 100% continuous torque is needed at low
speeds.
Insulation Tolerance
NOTICE: Consider motor voltage tolerance levels and motor insulation in applications with an input voltage of over 440 V or particularly
long wiring distances.
High-Speed Operation
NOTICE: Problems may occur with the motor bearings and dynamic balance of the machine when operating a motor beyond its rated speed.
Contact the motor or machine manufacturer.
Torque Characteristics
Torque characteristics differ compared to operating the motor directly from line power. The user should have a full
understanding of the load torque characteristics for the application.
Vibration and Shock
The drive allows selection of high carrier PWM control and low carrier PWM. Selecting high carrier PWM can help reduce
motor oscillation.
• Take particular caution when adding a variable speed drive to an application running a motor from line power at a constant
speed. If resonance occurs, install shock-absorbing rubber around the base of the motor and enable the Jump frequency
selection to prevent continuous operation in the resonant frequency range.
• Mechanical resonance can occur with long motor shafts and in applications such as turbines, blowers, and fans with high
inertia loads. Use Closed Loop Vector Control when these applications experience mechanical resonance problems.
Audible Noise
Noise created during run varies by the carrier frequency setting. When using a high carrier frequency, audible noise from the
motor is comparable to the motor noise generated when running from line power. Operating above the rated motor speed can
create unpleasant motor noise.
n Synchronous Motors
• Contact Yaskawa or a Yaskawa agent when planning to use a synchronous motor not endorsed by Yaskawa.
• Use a standard induction motor when running multiple synchronous motors simultaneously. A single drive does not have
this capability.
• A synchronous motor may rotate slightly in the opposite direction of the Run command at start depending on parameter
settings and rotor position.
18
25% ED (or 15 min)
40% ED (or 20 min)
100
90
80
70
60
Torque
(%)
50
3 6
Figure i.2 Allowable Load Characteristics for a Yaskawa Motor
YASKAWA ELECTRIC TOEP C710616 41B YASKAWA AC Drive - A1000 Quick Start Guide
Figure i.2 shows the allowable load characteristics for a Yaskawa
60% ED (or 40 min)
Continuous operation
20 60
Frequency (Hz)