Control Techniques Unidrive Regen Installation Manual page 37

There are three main connection differences compared with normal operation.
• There are AC supply connections to both the Regen and motoring drives.
• The DC bus connection between the Regen and motoring drives is via diode D1.
• The switching frequency filter inductors are replaced with an isolating transformer T1 with a defined leakage inductance
For details of the standard Regen components and their connections, refer to Chapter 3 Power connections on page 4 and Chapter 5 Components on
page 10.
A.5.1 DC bus diode
Table A-2 DC bus diode
Recovery time
Diode type
Fast or Ultra Fast
A suitable supplier for the above diode can be Semikron
The diode must be mounted on a suitable heatsink. Heatsink sizing should be based on:
• Maximum device case temperature of 80°C
• Power loss = 2V x Regen drive rated current
A.5.2 Isolating transformer T1
This is a three phase transformer which provides isolation between the AC supply and the Regen drive. One isolating transformer can only supply
one Regen drive with the current rating equal to the Regen drive continuous current rating. The transformer leakage inductance forms the switching
frequency filter inductance. The inductance value for the switching frequency filter is specified in Chapter 5 Components on page 10.
N
NOTE
A non isolating transformer cannot be used under any circumstances.
Unidrive Regen Installation Guide
Issue Number: 2
Current rating
µS
A
3 x current rating of
<1
Regen drive
TM
with the SKKD xxx F 12 or SKKE xxx F 12 diode modules.
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Voltage rating
V
1,200
33