AC70 VC CONTROL FREQUENCY INVERTER MANUAL
PERIPHERAL EQUIPMENTS AND OPTIONS
68
Run at low speed
One frequency inverter run multi motors
Motor cable is very long
Detect malfunction mistakenly for carrier frequency is too high
Low speed and heat relay
In normal case, the heat relay is suitable for the universal motor. While using the frequency inverter to run the universal
motor (standard motor), the motor current is 5-10% bigger, comparing with the commercial power supply. Besides, at
low speed, even in the motor rated current range, the cooling capability of the fan driven by the motor axis will reduce,
which will bring motor overheat. So please set the motor overheat protection current [E-49] in the frequency inverter to
be valid.
Motor cable is very long
While the motor cable is very long and the carrier frequency is very high, impacted by the leakage current, the heat
relay may fail. To avoid it, please reduce the carrier frequency or set higher detection value of the heat relay. Before
enhancing the detection value, do confirm whether there is other cause for the motor overheat. Otherwise there is
danger.
