Danfoss VLT AQUA Drive FC 202, Operating Manual

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7.1.15 Wiring Configuration for Lead Pump Alternation
1
3
0
B
A
3
7
7
.1
3
L1/L2/L3
Drive
L1/L2/L3 L1/L2/L3
K3
K2
K3
K1
K2
K1
K1 K1
K4
K3
K4
K3
R
e
la
y
1
R
e
la
y
2
Illustration 47: Lead Pump Alternation Wiring Diagram
Every pump must be connected to 2 contactors (K1/K2 and K3/K4) with a mechanical interlock. Apply thermal relays or other motor
overload protection devices according to local regulation and/or individual demands.
•
Relay 1 (R1) and relay 2 (R2) are the built-in relays in the drive.
• When all relays are de-energized, the 1
st
built-in relay that is energized cuts in the contactor corresponding to the pump controlled
by the relay. For example, relay 1 cuts in contactor K1, which becomes the lead pump.
• K1 blocks for K2 via the mechanical interlock, preventing mains from being connected to the output of the 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 1
st
relay.
For a detailed description of commissioning for mixed pump and master/slave applications, refer to VLT
®
Cascade Controller Options
MCO 101/102 Operating Instructions.
Wiring Configuration Examples
Operating Guide | VLT® AQUA Drive FC 202
AQ275652274277en-000101 / 130R0708| 97
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