Plenty of payback from variable-frequency drives

It is no secret that utilities in various states run rebate programs for motor installations that aid in conserving and improving energy efficiency. Less well known is the fact that these programs may cover variable speed drives (VSD), also known as adjustable speed drives (ASD) or variable frequency drives (VFD). The rebate amount depends upon the size of the drive and motor, and varies by state.

In one recent installation, industrial distributor Kaman Industrial Technologies Corp. (Windsor, Ct.) worked with a customer in central New York that used five Baldor Electric Co. VS1PF drives on various boiler and kiln fan applications. Utility rebates totaled $7,650, representing 75% of the hardware costs, Kaman says. “The incentives on rebates can be as high as $13,000 for a 200-hp drive in some markets in the Northeast,” says Kaman automation program manager Ted Clayton.

The Baldor VS1PF family covers the range from 5 to 700 hp and targets variable-speed fan and pump applications. The VSDs can adjust output automatically based on load to save energy. A manual mode lets users set the amount of savings manually. As an example, for an application with a 60% motor load factor, operation with a VSD will reduce the annual kilowatt usage approximately 60%. If the load factor is 70%, the reduction in kilowatt usage is 50%.

Numerous rebate programs can apply to many other application retrofits and upgrades which can save energy. According to the Energy Center of Wisconsin, applications for pumps and compressors could realize up to 25% energy savings; fans, blowers and centrifugal refrigeration systems up to 35% savings; and boiler fans and feed water pumps up to 50% savings. Utilities are willing to discuss methods of saving energy and users are encouraged to contact their local utility.