Wire-to-water efficiency equals which product?

Wire-to-water efficiency equals which product?

• A. Motor efficiency
• B. Pump efficiency
• C. Power factor x pump efficiency
• D. Power factor plus pump efficiency

Answer: (C)

Wire-to-water efficiency is the fraction of electrical power that actually ends up as hydraulic power in the water. To get that, you look at the real electrical power delivered to the pump, which is voltage times current times the power factor (that’s the portion of apparent power that does real work). Then you account for how efficiently the pump converts that shaft power into water power, which is the pump efficiency. Multiply these two factors: PF × pump efficiency. This product gives the overall efficiency from the electrical input (the wire) to the water output. For example, with a PF of 0.9 and a pump efficiency of 0.8, the wire-to-water efficiency is 0.72.

Wire-to-water efficiency is the fraction of electrical power that actually ends up as hydraulic power in the water. To get that, you look at the real electrical power delivered to the pump, which is voltage times current times the power factor (that’s the portion of apparent power that does real work). Then you account for how efficiently the pump converts that shaft power into water power, which is the pump efficiency. Multiply these two factors: PF × pump efficiency. This product gives the overall efficiency from the electrical input (the wire) to the water output. For example, with a PF of 0.9 and a pump efficiency of 0.8, the wire-to-water efficiency is 0.72.