NO.8 Selection and Configuration of Peripheral Facilities
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No.8 Selection and Configuration of Peripheral Facilities
8.1 Options
Name
Function
Breaker and leakage switch
for connection
Protect the connection of inverter, be sure to set breaker
on power side, and please use the leakage switch with
higher harmonic prevention
Electromagnetic contactor
Set electromagnetic contactor to prevent burning out
brake resistor and connect surge absorber while
applying.
Surge absorber
Absorb switching surge current of electromagnetic
contactor and relay for controlling
Isolation transformer
Isolate input and output effects of the inverter and
produce effect on reducing the interference
DC reactor
Improve input power factor of the inverter
AC reactor
Improve input power factor of the inverter and prevent
surge voltage impact
Brake resistor and brake unit
Consume recovered energy of the motor and shorten
deceleration time
1. Leakage switch
The inside of inverter, inside of motor and input and output leads have earth electrostatic
capacitance and the inverter has relatively high carrier frequency, so large earth leakage
current is induced to the inverter, which is more obvious for high-capacity machines; the
application of leakage switch may cause misoperation of protection circuit, so the attention
should be paid to the selection of leakage switch during the application, simultaneously
carrier frequency shall be reduced and the lead shortened appropriately.
2. AC reactor
AC reactor can be used for suppressing higher harmonic of inverter input current, improving
input power factor of the inverter and preventing leakage-induced impact. It is suggested to
use input AC reactor under following circumstances:
1) Unbalanced three-phase power;
2) The same power supply is connected with thyristor or switch-controlled power factor
compensating device;