Danfoss VLT AQUA Drive FC 202 Design Manual

5.11 Load Share Overview
Load share is a feature that allows the connection of DC
circuits of several drives, creating a multiple-drive system
to run 1 mechanical load. Load share provides the
following benets:
Energy savings
A motor running in regenerative mode can supply drives
that are running in motoring mode.
Reduced need for spare parts
Usually, only 1 brake resistor is needed for the entire drive
system instead of 1 brake resistor per drive.
Power back-up
If there is mains failure, all linked drives can be supplied
through the DC link from a back-up. The application can
continue running or go through a controlled shutdown
process.
Preconditions
The following preconditions must be met before load
sharing is considered:
•
The drive must be equipped with load sharing
terminals.
•
Product series must be the same. Use only VLT
®
AQUA Drive FC 202 drives with other VLT
®
AQUA
Drive FC 202 drives.
•
Drives must be placed physically close to one
another to allow the wiring between them to be
no longer than 25 m (82 ft).
•
Drives must have the same voltage rating.
•
When adding a brake resistor in a load sharing
conguration, all drives must be equipped with a
brake chopper.
•
Fuses must be added to load share terminals.
For a diagram of a load share application in which best
practices are applied, see Figure 5.16. For more information
on load sharing applications, contact Danfoss.
130BF758.10
380 V
2x aR-1000 A 2x aR-1500 A
3x 1.2%
315 kW 500 kW
3x 1.2%
3x Class L-800 A
3x Class L-1200 A
M
Common mains
disconnect switch
Mains connecting point for
additional drives in the
load sharing application
DC connecting point for
additional drives in the
load sharing application
91
92
93
91
92
93
96
97
98
96
97
98
82 81 82 81
M
Figure 5.16 Diagram of a Load Share Application Where Best Practices are Applied
Load sharing
Units with the built-in load sharing option contain terminals (+) 89 DC and (–) 88 DC. Within the drive, these terminals
connect to the DC bus in front of the DC-link reactor and bus capacitors.
The load sharing terminals can connect in 2 dierent congurations.
•
Terminals tie the DC-bus circuits of multiple drives together. This conguration allows a unit that is in a
regenerative mode to share its excess bus voltage with another unit that is running a motor. Load sharing in this
manner can reduce the need for external dynamic brake resistors, while also saving energy. The number of units
Product Features Design Guide
MG22B222 Danfoss A/S © 01/2018 All rights reserved. 33
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Danfoss VLT AQUA Drive FC 202 Specifications

General

Brand	Danfoss
Model	VLT AQUA Drive FC 202
Category	DC Drives
Language	English