Yaskawa Matrix Converter - Manual (Page 377)

MxC Application Precautions
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„ When Using a Generator as a Power Supply
• Select the generator capacity approximately twice as large as the MxC input power supply capacity. For
further information, contact your Yaskawa representative.
• Set the deceleration time or load so that the regenerative power from the motor will be 10% or less of the
generator capacity.
„ When a Phase Advance Capacitor or Thyristor Controller is Provided for the Power
Supply
No phase advance capacitor is needed for the MxC. Installing a phase advance capacitor to the VS-656DC5
will weaken the power factor.
For the phase advance capacitor that has already been installed on the same power supply system as the MxC,
attach a phase-advance capacitor with a series reactor to prevent oscillation with the MxC.
Contact your Yaskawa representative, if any device generating voltage surge or voltage distortion such as DC
motor drive thyristor controller or magnetic agitator is installed on the same power supply system.
„ Prevention Against EMC (Radio Noise) or Harmonic Leakage Current
Preventive actions against EMC (radio noise) or harmonic leakage current are necessary for the MxC as well
as for general inverter drives.
If a device that will be affected by noise is near the MxC, use a zero-phase reactor as a noise filter.
Use a leakage relay or an ground leakage breaker designed for inverters (products provided with prevention
from harmonics leak current), when necessary.
„ Guidelines for Harmonic Reduction
A guideline for handling problems with harmonics is available for users who receive 6.6 kVA or more from
the power supply system.
„ Affects of Power Supply Distortion
When the power supply voltage is distorted, or when several devices are connected in parallel to the same
power supply, the harmonics contents increase because the harmonics of the power supply system enter the
Varispeed AC.
„ Applications Requiring Frequent Stops and Starts
Applications with repetitive loads such as cranes, elevators, presses, and washing machines must be derated to
handle the load. Derating refers to a reduction of the carrier frequency and current, and involves a change to
accel/decel timing and increasing the frame size of the MxC.
Contact your Yaskawa representative for more information.
„ Initial Torque
The startup and acceleration characteristics of the motor are restricted by the overload current ratings of the
MxC that is driving the motor. The torque characteristics are generally less than those required when starting
the motor with a normal commercial power supply. If a large initial torque is required, select an MxC with a
somewhat larger capacity or increase the capacity of both the motor and the MxC.