Showing posts from July, 2014

We Know That You Believe in Motor Protection!

But, are you protecting your motor from regenerative voltages too? Check the specs on the units you are using now Make sure they state "% unbalance" Symcom's products do! During phase loss, a motor can regenerate more than 92% of the supply voltage in the open phase. This phenomenon occurs because the disconnected winding acts as a generator. This regenerative voltage can fool “voltage averaging” and “phase shift detecting” voltage monitors into believing that a phase loss is not occurring. For proper protection, a voltage monitor MUST sense 6% to 8% unbalance; otherwise, phase loss may not be detected. As with all SymCom 3-phase voltage monitors, our new 201-XXX-DPDT protects against regenerative voltages by detecting small voltage unbalances. The 201-XXX-DPDT family of products has a fixed 6% voltage unbalance trip point making them better than the NEC standard of 8%. The 201-xxx-DPDT is used to prevent damage caused by incoming voltage problems, includ