5.5 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 benefits:
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 for 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 though 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
®
AutomationDrive FC 302 drives with other VLT
®
AutomationDrive
FC 302 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 configuration, 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
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
Illustration 5.9 Diagram of a Load Share Application Where Best Practices are Applied
Product Features
Design Guide
MG38C202
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