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3.1.3 Fixed-speed Pump Configuration
In this configuration, a single drive controls one variable speed pump and up to 7 fixed-speed pumps. The fixed-speed pumps are staged and de-staged
as needed directly online through contactors. The single pump connected to the drive provides the finer level of control needed between the stages.
The direct-online pumps are staged or de-staged depending on the feedback.
Figure 3.3: Example
For this configuration, relay selections in Group 27-7* “Connections” are as follows:
27-70 RELAY 1
→
[73] Pump 2 to Line Power
27-71 RELAY 2
→
[74] Pump 3 to Line Power
27-72 RELAY 10
→
[75] Pump 4 to Line Power
27-73 RELAY 11
→
[0] Standard Relay
27-74 RELAY 12
→
[0] Standard Relay
The fixed speed pump configuration provides a cost effective method for controlling up to 6 pumps. It is able to control system output by controlling the
number of running pumps as well as the speed of the single variable speed pump. It will however produce wider pressure fluctuations during staging/
de-staging transitions and it may be less energy efficient than the Master-Follower configurations.
Extended and Advanced Cascade Controller
Option
3 Supported Configuration
MI.38.C2.22 - VLT
®
is a registered Danfoss trademark
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