Fixed Variable-Speed Pump Wiring Diagram; Lead Pump Alternation Wiring Diagram; Cascade Controller Wiring Diagram - Danfoss VLT HVAC Drive FC 102 Design Manual

Application Examples
6.1.11 Fixed Variable-speed Pump Wiring
Diagram
Figure 6.9 Fixed Variable-speed Pump Wiring Diagram
6.1.12 Lead Pump Alternation Wiring
Diagram
L1/L2/L3
L1/L2/L3
FC
k3 k3
k2 k1
K2
K1 K3
Figure 6.10 Lead Pump Alternation Wiring Diagram
MG16C122
Design Guide
L1/L2/L3
K1
K1
K4
K3
K4
Danfoss A/S © Rev. 2014-01-13 All rights reserved.
Every pump must be connected to two contactors (K1/K2
and K3/K4) with a mechanical interlock. Apply thermal
relays or other motor protection devices according to local
regulation and/or individual demands.
•
Relay 1 (R1) and Relay 2 (R2) are the built-in
relays in the adjustable frequency drive.
•
When all relays are de-energized, the first built in
relay to be energized cuts in the contactor
corresponding to the pump controlled by the
relay.
•
K1 blocks K2 via the mechanical interlock,
preventing line power to be connected to the
output of the adjustable frequency drive (via K1).
•
Auxiliary break contact on K1 prevents K3 from
cutting in.
•
RELAY 2 controls contactor K4 for on/off control
of the fixed-speed pump.
•
At alternation both relays de-energize and now
Relay 2 is energized as the first relay.

6.1.13 Cascade Controller Wiring Diagram

The wiring diagram shows an example with the built-in
BASIC cascade controller with one variable-speed pump
(lead) and two fixed-speed pumps, a 4–20 mA transmitter
and system safety interlock.
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