View Full Version : 3PH 480V motor wiring and tripping on overload
NEWBIE TINMAN
May 15, 2009, 12:47 PM
:confused:REPLACED EXISTING DAYTON MOTOR WITH EXACT MODEL NUMBER. 3PH 480V
WIRED IT EXACTLY AS SHOWN ON NAME PLATE. KEEP TRIPPNG BREAKER. NAME PLATE INDICATES 1.9AMP FULL LOAD. I MEASURE 3.4AMP. MOTOR IS USED FOR BELT DRIVEN
BLOWER. IREMOVE BELT AND I HAVE 1.4AMP READING IS THIS NORMAL(NO LOAD) READING.
hvac1000
May 15, 2009, 11:15 PM
Check all 3 legs of the circuit for exact voltage readings. Low voltage on one or more legs will cause the problem you are having.
tkrussell
May 16, 2009, 04:40 AM
Could be possible that rotation is incorrect. This would cause the FLA to increase beyond the nameplate FLA, and cause the overload to trip.
If so, just swap any two leads of the 3 phase wiring.
Or the pulley or fan that the belt is driving could be stiff, bound, or otherwise too tight, bad bearing, for example, which would cause the FLA to be too high.
hvac1000
May 16, 2009, 05:19 AM
On a belt driven blower a reverse rotation will cause less of a load since it will not be moving the air since the wheel will not be scooping up the air. Now a adjustable pully can cause problems if not adjusted properly.
jerro
May 16, 2009, 06:17 AM
Are you tripping the main breaker for the ac unit or tripping the overlaod heaters. This makes a difference as to what to look for. What was the reason for changing the motor?