Quad Plus Offers SPR Drive for Shredders

Quad Plus Inc., Joliet, Ill., is now offering the SPR (slip power recovery) drive as an alternative to liquid rheostat models used in auto shredder systems. The company says the “innovation is significant because SPR drives will increase auto shredders’ productivity, lower energy costs and reduce maintenance.”

According to a Quad Plus news release, liquid rheostats are commonly used to start and control large AC wound rotor motors for auto shredders. SPR drives, which other industries have adopted to control AC wound rotor motors, are now being made available to the scrap recycling industry.

SPR Drives can improve productivity because they can keep the motor speed near synchronous speed through load hits, according to Quad Plus. When the motor current reaches a pre-defined current limit (such as 190 percent or 250 percent) the speed will drop. But it will recover more quickly than with the liquid rheostat, according to the company.

Additionally, the SPR drive will regenerate “excess power and sell it back to the power company, providing a significant energy savings for the recycler.

Because it is a solid state piece of equipment the SPR drive will not require the same types of maintenance associated with a liquid rheostat and no cooling tower is needed, according to Quad Plus. Also, the SPR drive will operate at unity (1.0) power factor, so no capacitors are required.

More information on Quad Plus and the SPR drive can be obtained from the company’s Web site at www.quadplus.com.