Sun Pumps SCB-10-150-120 BL - Manual (Page 12)

Output Power Limit Circuit (Motor Speed Control)
The Output Power Limit Control circuit is used to control the speed of the pump motor and thus the flow
rate of the pump. It is primarily used for low producing wells where the pump output is matched to the
production rate of the well. However it can also be used any time specific flow rates are required.
Output Power Limit Adjustment
The purpose of this procedure is to adjust the output power of the controller and thus reduce the water flow
of the pump. If tests have shown the pump will out produce the well capacity, then the controller “Speed
Control” feature can be used to match the flow rate of the pump to the production of the well.
1. With the system installed and controller properly configured, allow the pump to run at full power at
mid-day until the pump starts surging.
2. Slowly turn the “Speed Control” trim pot located on the face of the controller counter clockwise until
the pump stops surging. This is the point where the pump flow rate equals the well production. This
process will probably take a few attempts to “balance” the system for optimum water production. If
maximum water is not a critical issue you may want to reduce the pumps flow rate an additional 5% to
10% to insure the pump will not run dry.
(NOTE: The trim pot has a15- turn range. It usually takes many complete turns in a counter-clockwise
direction before you will notice any change in water output or output power on the display).