Ac And Dc Reactor - Delta EB3000 Series User Manual

Chapter 11 Optional AccessoriesEB3000

11-4 AC and DC Reactor

AC Input Reactor
Installing an AC reactor on the input side of an AC motor drive can increase line impedance,
improve power factor, reduce input current, and reduce interference generated from the motor drive. It
also reduces momentary voltage surges or abnormal current spikes. For example, when the main
power capacity is higher than 500 kVA, or when using a switching capacitor bank, momentary voltage
and current spike may damage the AC motor drive's internal circuit. An AC reactor on the input side of
the AC motor drive protects it by suppressing surges.
Installation
Install an AC input reactor in series with the main power to the three input phases R S T as
shown in the figure below:
AC Output Reactor
When using drives in long wiring output application, ground fault (GFF), over-current (oc) and
motor over-voltage (ov) often occur. GFF and oc cause errors due to the drive's self-protective
mechanism; over-voltage damages motor insulation.
The excessive length of the output wires makes the grounded stray capacitance too large,
increase the three-phase output common mode current, and the reflected wave of the long wires
makes the motor dv / dt and the motor terminal voltage too high. Thus, installing a reactor on the
drive's output side can increase the high-frequency impedance to reduce the dv / dt and terminal
voltage to protect the motor.
Installation
Install an AC output reactor in series between the three output phases U V W and the motor, as
shown in the figure below:
11-8