Notes On Motor Operation - YASKAWA A1000 Technical Manual

Even when the power has been shut off for a drive running a PM motor, voltage continues to be generated at the motor
terminals while the motor coasts to stop. Take the precautions described below to prevent shock and injury:
• In Applications where the machine can still rotate even though the drive has fully stopped a load switch for
disconnecting motor and drive should be installed to the output side of the drive.
• Do not allow an external force to rotate the motor beyond the maximum allowable speed, also when the drive has been
shut off.
• Wait for at least the time specified on the warning label after opening the load switch on the output side before
inspecting the drive or performing any maintenance.
• Do not open and close the load switch while the motor is running, as this can damage the drive.
• If the motor is coasting, make sure the power to the drive is turned on and the drive output has completely stopped
before closing the load switch.
Wiring
All wire ends should use ring terminals for UL/cUL compliance. Use only the tools recommended by the terminal
manufacturer for crimping.
Transporting the Drive
Never steam clean the drive.
During transport, keep the drive from coming into contact with salts, fluorine, bromine, phthalate ester, and other such
harmful chemicals.
 Notes on Motor Operation

Using a Standard Motor
Low Speed Range
The cooling fan of a standard motor is usually designed to 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. To prevent motor damage from overheat, reduce the load torque as the motor slows.
Insulation Tolerance
Consider voltage tolerance levels and insulation in applications with an input voltage of over 440 V or particularly long
wiring distances. Contact YASKAWA or your YASKAWA agent for consultation.
High Speed Operation
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
A1000 lets the user choose between high carrier PWM control and low carrier PWM. Selecting high carrier PWM can
help reduce motor oscillation.
• Take particular caution when using a variable speed drive for an application that is conventionally run from line power
at a constant speed. If resonance occurs shock-absorbing rubber should be installed around the base of the motor and
the Jump frequency function should be enabled 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 min
however, can create unpleasant motor noise.
YASKAWA ELECTRIC SIEP C710616 27G YASKAWA AC Drive A1000 Technical Manual
i.2 General Safety
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