A 460 volt motor driven pump consumes 7 hp pumping water from ground level to an elevated tank. The pump and motor are in an enclosed pump house. The input amperage at the motor is measured to be 10 amps. Assume the motor power factor is 0.80. What is the expected heat output to the pump house?
Convert input power to hp:
Efficiency is calculated as:
The motor is 81.9% efficient which means that 100-81.9 = 18.1% of the incoming power is being lost. There are no other sources of power loss mentioned in the problem statement so assume the 18.1% of power is lost due to heat. Therefore:
Converting hp to btu/min gives:
The heat input to the pump house is approximately 65.5 btu/min.
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