
8-43
Operating the Drive
890CS Common Bus Supply - Frames B & D; 890CD Common Bus Drive and 890SD Standalone Drive - Frames E & F
Pre-Charge Sizing
The external pre-charge contactor is required to carry the full load current rating (including overload) of the
4-Q Regen drive. Thus, it must have an AC1 rating of the Constant Duty current rating of the drive. Refer
to the Electrical Ratings tables for Constant Duty motor powers.
We recommend that standard SSD Dynamic Braking resistors are used for the external pre-charge circuit.
The continuous and peak power capabilities of these resistors are given below:
SSD Part N
o
Resistance
(
Ω
)
Continuous Power Rating
(W)
Peak Power Rating
(kW)
CZ389853
100
100
2.5
CZ463068
56
200
5
CZ388396
36
500
12.5
The recommended pre-charge resistor networks are shown in the table below. The table indicates the
amount of total DC Link capacitance the network can charge for a given supply voltage.
External Pre-Charge
Network
Continuous
Power Rating
(W)
Impulse Joule
Rating (J)
Pre-Charge
Capability (
µ
F) @
240V
rms
+10%
Pre-Charge
Capability (
µ
F) @
460V
rms
+10%
100 Ohm 100W
100
2,500
35,000
9,700
56 Ohm 200W
200
5,000
71,000
19,500
36 Ohm 500W
500
12,500
179,000
48,800