ACHRNEWS

SUNDAY - January 28, 2001: Save Here But Spend There

January 28, 2001
ATLANTA, GA – At the ASHRAE 2001 Winter Meeting here, Forum 1 – “Are We Robbing “Peter Transformer” to Pay “Paul Motor”? – discussed whether users really are getting savings when they switch to high-efficiency motors.

The question was posed: Are efficiency improvements of motors being eaten up by additional transformer losses?

One consultant stated, “It’s difficult to measure savings. You save on efficiency but you pay on power factor penalty.”

A utility representative noted that one customer installed a new high-efficiency motor that pulled nine times the inrush current. The company then had to change to a larger transformer just to start the motor. So a 2% gain in efficiency required the added expense of a new, larger transformer.

Another consultant remarked that guidelines are based on past experience not on current systems. “The load profile has changed dramatically and our rating systems haven’t kept up with it.”

Are new guidelines needed? The consensus of opinion was yes.