Danfoss VLT Series Design Manual page 79

VLT ® HVAC Drive Design Guide
3.6.8. 24 V Backup Option MCB 107 (Option D)
External 24 V DC Supply
An external 24 V DC supply can be installed for low-voltage supply to the control card and any
option card installed. This enables full operation of the LCP (including the parameter setting) and
serial communication busses without line power supplied to the power section.
External 24 V DC supply specification:
Input voltage range
Max. input current
Average input current for the adjustable frequency drive
Max. cable length
Input capacitance load
Power-up delay
The inputs are protected.
Terminal numbers:
Follow these steps:
1.
2.
3.
4.
5.
6.
When MCB 107, 24 V backup option is sup-
plying the control circuit, the internal 24 V
supply is automatically disconnected.
3.11: Connection to 24 V back-up supplier (A2-
A3).
Terminal 35: - external 24 V DC supply.
Terminal 36: + external 24 V DC supply.
Remove the LCP or blind cover.
Remove the terminal cover.
Remove the cable decoupling plate
and the plastic cover underneath.
Insert the 24 V DC backup external
supply option in the option slot.
Mount the cable decoupling plate.
Attach the terminal cover and the
LCP or blind cover.
MG.11.B4.22 - VLT ® is a registered Danfoss trademark.
3. VLT HVAC Selection
24 V DC ±15% (max. 37 V in 10 s)
3.12: Connection to 24 V back-up supplier (A5-
C2).
3
2.2 A
0.9 A
246 ft [75 m]
< 10 uF
< 0.6 s
79