Of the 2 million industrial motors sold nationwide each year, energy efficient motors represent only 15 percent of the sales. That figure is probably even lower in the Northwest where electricity is cheap. Less slippage in energy efficient motors results in speeds about 1% faster than in standard counterparts. Energy efficient motors maintain high efficiency at low loads. They usually have inherently higher power factors than standard motors and maintain higher power factors under partial load operations.
For this reason, energy-efficient motors make economic sense: In an industrial application operating 4,000 hours/year, energy-efficient motors earn back their initial cost in two years. Carbon dioxide emissions and operating costs are reduced thanks to low power consumption. At smaller load factors motor efficiency is lower, leading to increased operating costs. Select a lower power motor and operate it at a higher load factor to help justify the motor replacement.
EISA does not affect any inventories of electric motors. The law only applies to new motors manufactured after December 17. A majority of industrial drives use electric motors. The added advantage is that the three phase motor is more efficient.
Motors that meet or exceed NEMA Premium efficiency standards have even lower losses. The standard is part of an effort to unify motor testing standards, efficiency requirements and product labeling requirements so that motor purchasers worldwide have the ability to easily recognize premium-efficiency products.
Analyzing the efficiency of motors and their controllers can be a bit tricky at times. However, S. Sankar provides a novel way of looking at the relationship:
A novel analysis of energy efficiency motors and power controllers. Voltage Control Voltage alone can be used as a source of intelligence when the switched capacitors are applied at point where the circuit voltage decreases as circuit load increases.
According to Sankar, Voltage is a key player:
Voltage alone can be used as a source of intelligence when the switched capacitors are applied at point where the circuit voltage decreases as circuit load increases. Generally, where they are applied the voltage should decrease as circuit load increases and the drop in voltage should be around 4 ‘ 5 % with increasing load.
Whether or not these analysis attempts are the most efficient way of measuring remains to be seen. However, looking at something in a different way provides innovative approaches never before considered.
