Supplying The Unidrive M / Unidrive Hs Size 7, 8 And 9A Drives With Dc / Dc Bus Paralleling; 24 Vdc Supply - Emerson Unidrive M201 Installation Manual

4.3 Supplying the Unidrive M / Unidrive HS size 7, 8 and 9A
drives with DC / DC bus paralleling
The drive may be supplied with DC instead of 3 phase AC.
The connecting of the DC bus between several drives is typically used to:
1. Return energy from a drive which is being overhauled by the load to a second motoring drive.
2. Allow the use of one braking resistor to dissipate regenerative energy from several drives.
There are limitations to the combinations of drives which can be used in this configuration.
For further information, contact the supplier of the drive.
Unidrive M/Unidrive HS size 9E and 10E drives do not have an accessible negative DC
NOTE
terminal. It is recommended that 9D and 10D drives are used as an alternative when this
is needed, please refer to the Modular Installation Guide for further details.
4.4

24 Vdc supply

The 24 Vdc supply connected to control terminals 1 & 2* provides the following functions:
• It can be used to supplement the drive's own internal 24 V supply when multiple option modules
are being used and the current drawn by these module is greater than the drive can supply.
• It can be used as a back-up power supply to keep the control circuits of the drive powered up
when the line power supply is removed. This allows any fieldbus modules, application modules,
encoders or serial communications to continue to operate.
• It can be used to commission the drive when the line power supply is not available, as the display
operates correctly. However, the drive will be in the Under voltage state unless either line power
supply or low voltage DC operation is enabled, therefore diagnostics may not be possible.
(Power down save parameters are not saved when using the 24 V back-up power supply input).
• If the DC bus voltage is too low to run the main SMPS in the drive, then the 24 V supply can be
used to supply all the low voltage power requirements of the drive. Low Under Voltage Threshold
Select (06.067)** must also be enabled for this to happen.
** Not available on Unidrive M200 to M400
The power 24 Vdc supply (terminals 51, 52) must be connected to enable the 24 V dc
NOTE
supply to be used as a backup supply, when the line power supply is removed. If the power
24 Vdc supply is not connected none of the above mentioned functions can be used,
"Waiting For Power System" will be displayed on the keypad and no drive operations are
possible. The location of the power 24 Vdc can be identified from Figure 4-5 and Figure
4-6 Location of the 24 Vdc power supply connection on size 8 to 10 on page 61.
Table 4-5 24 Vdc Supply connections
Function
Supplement the drive's internal supply
Back-up supply for the control circuit
* Terminal 9 on Unidrive M702 and HS72 (24 Vdc control supply on Unidrive M200 to M400 is
supplied via AI-Backup Adaptor)
Unidrive M / HS Frame 7 to 10 Power Installation Guide
Issue Number: 5
.
Sizes 7-10
Terminal
1, 2*
Terminal
1, 2*
51, 52
59