Motor overload tripping

Status
Not open for further replies.
J

JdoubleU

Senior Member
One of our air compressors keeps tripping out on overload. The motor is only stamped for 230 volt but we are only feeding it with 208. Is it ok to use a 230 volt motor or will it eventually burn out? It is running about 3 amps over its FLA. Not sure why they did this but alot of the motors here are just stamped for 230v.
 
I would install two small buck / boost transformers and get the line to line voltage to 236 volts. (The resulting voltage from a standard buck / boost.)


ANSIC841.jpg


A motor simply marked 230 is designed for a 240 volt supply.
 
Jakewhis said:
One of our air compressors keeps tripping out on overload. The motor is only stamped for 230 volt but we are only feeding it with 208. Is it ok to use a 230 volt motor or will it eventually burn out? It is running about 3 amps over its FLA. Not sure why they did this but alot of the motors here are just stamped for 230v.
Click to expand...
I've had a couple of these where the source was 3ph, 208V, and some small motors were 3ph, 230V, 1.0sf, and fully loaded. They ran hot, ocassionally tripped, and would finally burn up.

I bought 200V, 1.15sf motors for replacement, same frame, same mounting. Changed the overloads to match the new fla. Amazingly the problems went away.

I don't know why the original designers/vendors supplied 230V tin-can motors either. Wait a second - yes I do. They were $1.40 less.:roll:

cf
 
Cold Fusion said:
. Wait a second - yes I do. They were $1.40 less.:roll:

cf
Click to expand...

Here in grain farming country I have always wondered why the bin fan manufacturers always put open drip proof motors on many of their fans. They have nothing but trouble with them until they eventually need replaced. Being open type motor it will run cooler, but insects get in them and interfere with the centrifugal start switch or when it rains it seldom falls straight down but is wind driven and enters the motor as well as blowing dirt ends up inside the motor. We replace them with totally enclosed motors when they totally fail and have much less trouble with them.

They also are probably $1.40 less than the totally enclosed motors:mad:
 
another thing to think about when trying to run a 230 volt motor on 208 is startup current, the motor will take much more time to reach cruising speed, thus causing very much more heat in the windings, if it has a adjustable shiv you could possibly reduce the FLA back in to range, but not the startup current, so the only method of fix is get the proper motor or do a buck boost, try to find out who ordered the motor and see if this was a manufacture mistake which they would need to fix by sending out the correct motor.
 
While some equipment seems to be a bit voltage tolerant, air compressors are notoriously engineered to max the motors and the low voltage is often a killer. I agree with Bob, it's Buck n Boost time..
 
iwire said:
I bet they can be ordered with TEFC motors for an up charge.
Click to expand...

If it were up to me that is what I would do.

Problem is the equipment guys sell them with the bin and install it. All I do is run power to it and then service it 6 months or a year later (or at least shortly after as there is no longer any warranty) after it has failed primarily because it was not TEFC.

They have to underbid their competitors so a 10 hp fan is a 10 hp fan, the less expensive one will do the job.
 
I had the same problem with a 20HP IR compressor in a truck repair shop being fed 208 instead of 230V. It was pulling at least 5-6 amps more than nameplate.
 
Status
Not open for further replies.
Top