Pool Main Pump Motor: Difference between revisions
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<b>IMPORTANT:</b> At this time, this section is for investigation purposes only. It has not been determined when/if a VFD will be implemented. | <b>IMPORTANT:</b> At this time, this section is for investigation purposes only. It has not been determined when/if a VFD will be implemented. | ||
=== Justification === | |||
As of Fall 2021, the pump is controlled by a Square D 8536 latching motor starter (relay). The pump is manually operated via start and stop pushbuttons. The flow rate is adjusted via the butterfly valve on the output side of the pump. | As of Fall 2021, the pump is controlled by a Square D 8536 latching motor starter (relay). The pump is manually operated via start and stop pushbuttons. The flow rate is adjusted via the butterfly valve on the output side of the pump. | ||
Removal of the motor starter and replacement with a VFD has been proposed. This system would be implemented prior to the 2022 swim season. | |||
* Motor speed can be automatically adjusted (via the [[Pool Systems Automation|automation system]]) to compensate for changes in flow rate due to the state of the strainer basket and sand filters. A constant and flow rate can be assured until the strainer basket or filters become too clogged. | Benefits to changing to the VFD include: | ||
* Motor speed can be automatically adjusted (via the [[Pool Systems Automation|automation system]]) to compensate for changes in flow rate due to the state of the strainer basket and sand filters. A constant and flow rate can be assured until the strainer basket or filters become too clogged. The automation system is NOT required to operate the drive. In the event that the automation system is not operational (or remote VFD control is disabled), the VFD can be operated with start and stop pushbuttons in a manner very similar to that of the motor starter. | |||
* No need for the operator (managers or B&G personnel) to regularly adjust the flow rate due to changing conditions. An improper flow rate: | * No need for the operator (managers or B&G personnel) to regularly adjust the flow rate due to changing conditions. An improper flow rate: | ||
** Violates best practices and/or health department requirements if too low (minimum number of complete water turn-over cycles per 24 hour period). | ** Violates best practices and/or health department requirements if too low (minimum number of complete water turn-over cycles per 24 hour period). | ||
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The sections below are theoretical at this point, describing possible operation for the VFD controls. | The sections below are theoretical at this point, describing possible operation for the VFD controls. | ||
==== Reset ==== | |||
The state of "reset" refers to the operating state of the safety relay. In order to operate the VFD, the safety relay must be reset by pressing the reset pushbutton. The safety relay cannot be reset if an <b>Emergency Stop</b> switch is tripped. | |||
Power failure will cause a loss of reset. Unfortunately, this is required for safety, as an electromechanical interlock ensures the motor will not start automatically (without explicit operator intervention). Even with a safety module, the electrical disconnect should still be used when maintaining the motor or pump. | |||
==== Run ==== | ==== Run ==== | ||
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==== Configuration ==== | ==== Configuration ==== | ||
This section is very preliminary - more details to follow. | |||
* Use Variable Torque (VT) mode for pump control (power is proportional to the cube of the speed). | * Use Variable Torque (VT) mode for pump control (power is proportional to the cube of the speed). | ||