Current = head * Flow
First, lift the level is determined by pipes and valves for water, energy loss and the decision, he said, can give the water pump energy value , of course, the motor speed also drops down when the pump head outlet valve off small , due to the head does not change, flow reduction, then the pump current is reduced , if it is fully closed the current minimum, but slightly larger than idling , because the water there is resistance .
Centrifugal minimum current when it is idling , it is not what the water pump body , and the atmosphere directly connected to the pump bye transfer [ of course submersible pumps such a long time can cause overheating switch is damaged , and even an ordinary pump , such transfer is not good.
The maximum pump current when it is connected to the source material when imported , such as water , while exports are not restricted, such as directly connected to the atmosphere , even the pipes are not connected , this time, the maximum flow rate , the pump current will be maximum .
However, the general manufacturers of pumps, motors are in accordance with the matching rated flow calculation , like this , when there is no restriction may cause motor overload burned, but the big manufacturers are not the same , they are usually matched according to the maximum limit of the motor , even without this restriction , maximum efficiency is not high , but the pump will not be damaged .