EQ7 Series Instruction Manual - TECO-Westinghouse Motor Company

• When the motor speed decreases significantly during coast-to-stop (with the current limiter activated):
• Secure more than 0.1 second after turning ON the "Switch to commercial power" signal before turning
ON a run command.
• Secure more than 0.2 second of an overlapping period with both the "Switch to commercial power"
signal and run command being ON.
• If an alarm has been issued or BX has been ON when the motor drive source is switched from the
commercial power to the inverter, the inverter will not be started at the commercial power frequency
and will remain OFF. After the alarm has been reset or BX turned OFF, operation at the frequency of
the commercial power will not be continued, and the inverter will be started at the ordinary starting
frequency.
To switch the motor drive source from the commercial line to the inverter, be sure to turn BX OFF
before the "Switch to commercial power" signal is turned OFF.
• When switching the motor drive source from the inverter to commercial power, adjust the inverter's
reference frequency at or slightly higher than that of the commercial power frequency beforehand,
taking into consideration the motor speed down during the coast-to-stop period produced by switching.
• Note that when the motor drive source is switched from the inverter to the commercial power, a high
inrush current will be generated, because the phases of the commercial power usually do not match the
motor speed at the switching. Make sure that the power supply and all the peripheral equipment are
capable of withstanding this inrush current.
• If "Restart after momentary power failure" (F14 = 3, 4, or 5), is activated keep BX ON during
commercial power driven operation to prevent the inverter from restarting after a momentary power
failure.
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