Unidrive Regen Installation Guide
13
Issue Number: 2
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5.7
RFI filter
In common with conventional drives, significant ground currents are generated by the capacitance of the motor to ground, the motor cables to ground,
and the drive power circuits to their heatsinks.The RFI filter will provide a relatively short return path for ground currents back to the drives power
circuit.
Table 5-7
RFI filter data
5.8
Varistors
AC line voltage transients can typically be caused by the switching of large items of plant, or by lightning strikes on another part of the supply system.
If these transients are not suppressed, they can cause damage to the insulation of the Regen input inductors, or to the Unidrive Regen drive
electronics.
Table 5-8
Varistors
N
Seven varistors are required when operating with an IT supply as shown in Figure 3-1 on page 5, Figure 3-2 on page 6 and Figure A-2 on page 32.
5.8.1
Configuration
Varistors should be fitted after the supply fuses, as shown in Figure 5-1:
Figure 5-1
Fitting of Varistors
CT Model
Number
Volts
Maximum
power
Filter
current
rating
Mounting style
Motor
cable
length
CT part
number
Vac
kW
A
m
UNI1405
480
4
10
Book End
100
4200-6105
Footprint or Book End
100
4200-6104
UNI2401 to 2402
480
7.5
16
Book End
100
4200-6109
Footprint or Book End
100
4200-6108
UNI2403
480
11
25
Book End
100
4200-6114
Footprint or Book End
100
4200-6113
UNI3401 to 3403
480
22
50
Book End
100
4200-6116
UNI3404
480
30
63
Book End
100
4200-6117
UNI3405
480
37
100
Book End
100
4200-6106
UNI4401 to 4402
480
55
150
Book End
100
4200-6107
UNI4403 to 4404
480
90
180
Book End
100
4200-6111
UNI4405
480
110
220
Book End
100
4200-6112
UNI5401
480
160
300
Book End
100
4200-6115
Do not use an RFI filter without the specified switching frequency filter, as failure of the RFI filter will occur, due to the switching currents.
Configuration
Drive
size
Varistor
voltage
Varistor
energy
Type number
Quantity
CT part number
Vac
J
Line to line
1 to 5
550
400
Z500NS
3
2482-1501
Line to ground
1 to 5
680
450
Z680LNS
3
2482-0680
CAUTION
NOTE
R
RFI
Filter
Switching
Frequency
Filter
E
Fuses
Varistors
Y
B
680Vac
varistors
550Vac
varistors