DRIVE CONFIGURATION
Multi-Drive Configuration
6
DRIVE CONFIGURATION
Multi-Drive Configuration
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Refer to the VFD Owner’s Manual for additional details as setup instructions will vary.
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The VFDs are configured to act as the central command structure for the package. One VFD is desig
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nated as the Master to provide cascade and speed control for all other VFD units.
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Master status can be switched between the VFDs by setting the correct parameter when the drive is in
Hand Mode and turned off.
•
The
package is configured to operate the pumps in a Lead/Lag fashion. Lead and lag roles are set by
the Master VFD.
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The lead pump designation will rotate so all VFDs will run about the same amount of time and not
exceed the hours set in the Pump Duty Switch Over Time parameter. Refer to
to modify this parameter with the Master VFD Control HMI Menu.
Pump Discharge Pressure Sensing
The pump discharge pressure is measured using one of the pressure transducers installed (per pump) and
wired into one of the analog inputs (AI). Refer to the VFD manual provided for the specific input terminal
number.
•
For VFD discharge pressure sensing during operation, refer to
“VFD Discharge Pressure Sensing”
.
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Refer to the VFD Owner’s Manual for additional details as setup instructions will vary.
Pump Suction Pressure Sensing
To prevent pump damage during periods of abnormally low suction pressure, each pump circuit is equipped
with a Low Pressure Switch (LPS) on the inlet side to the pump(s). The LPS is normally open and closes
above 5 PSI.
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The switch is wired into the enable circuit on each VFD control terminal connection block (digital
input) to keep the string powered and the VFD enabled as long as the switch reads pressures
above 5 PSI.
•
Refer to the VFD Owner’s Manual for additional details as setup instructions will vary.
