Veichi AC90 Manual page 74

AC90 TENSION CONTROL FREQUENCY INVERTER MANUAL
noise filter at the output side, the impact can be relieved. Please do not install the into phase capacitance and the noise
filter to the output circuit. Otherwise, there is danger of damage to the frequency inverter.
0-phase reactor
⑧
0-phase reactor is used for reducing the electromagnetic interference of the frequency inverter, which is suitable for the
input side and output side. It equals to a three-phase common mode inductance. In actual use, according to the actual
magnetic core size and cable specification, it is better to make sure 3-5 circles winding ratio to bring the best
performance.
Braking reactor or braking unit
⑨
Renewable electricity consumption unit, please see the sixth part of the chapter three "electric installation".
Heat relay
⑩
Please install the heat relay at the output side of the frequency inverter. When the motor enters into overload state, it
will cut the power source to protect the motor. While using one frequency inverter to drive one motor, it is unnecessary
to install heat relay. The motor overload protection current [FA.20] of the frequency will work. While using one frequency
inverter to drive multiple motors or the motor is drove directly by the power grid, please install heat relay between the
inverter and the motor. While installing the heat relay, please design to cut the sequence control circuit of the MC at the
main loop iuput side by the connection spot of the relay or design to input the heat relay action into the frequency
inverter as the exterior malfunction. And please pay attention to the following tips to avoid heat relay malfunction and
motor overheating at low speed.
Run at low speed
One frequency inverter run multiple motors
Motor cable is very long
Detect malfunction mistakenly for carrier frequency is too hig.
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% higher, comparing with the commercial power supply. Besides, at
low speed, even in the motor rated current range, the cooling capability of the fan drove by the motor axis will reduce,
which will bring motor overheat. So please set the motor overheat protection current [FA.20] in the frequency inverter to
be valid.
Motor cable is longer
While the motor cable is longer and the carrier frequency is higher, impacted by the leakage current, the heat relay
maybe malfunction. To avoid it, please reduce the carrier frequency or set higher detection value of the heat relay.
Before enhance the detection value, do confirm whether there is other cause for the motor overheat. Otherwise, there is
danger.
BASIC OPERATION AND TRIAL RUN
69