new guy on block asking question
new guy on block asking question
(OP)
Am new to the forum so HELLOOOO all,have a question,what effect is any would a 208/230 volts motor have if used in a 277 volts application 60 HZ both motor and system.
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new guy on block asking question
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RE: new guy on block asking question
If you are thinking this is a 3 phase issue, you have something wrong. 277V only esists as a Phase-to-Neutral 1 phase voltage on a 480V 3 phase 4 wire system. The 3 phase voltage would be 480, not 277.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: new guy on block asking question
RE: new guy on block asking question
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: new guy on block asking question
A 480:120 transformer connected as a 480 volt transformer with a 120 volt buck will produce 208 volts when fed from 277 volts.
The 120 volt winding must be rated for the motor full load amps.
respectfully.
RE: new guy on block asking question
jamcool,
jraef is right,
"..10% voltage, 208 to 277V is +33%."
For 1 phase, it burns up the machine.
For 3 phase, 30% variation would mean a single phase condition. Thus, it really burns up the motor.
RE: new guy on block asking question
RE: new guy on block asking question
BTW, waross made a good point about using standard off-the-shelf transformers.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: new guy on block asking question
RE: new guy on block asking question
Were it my system, I would invest in installing a transformer and step down to 220 or 230V, so that standard off-the-shelf motors will work forever more. Running that motor at +33% voltage is a fire waiting to happen, and a fire in an air handler can put your Hotel out of business for the time it takes to clean all the ducts and rooms it served.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: new guy on block asking question
Others have suggested transformers in the past but with 480 rooms (each has its own blower and chill water coil,480 at breaker then 277 lines to room, one line would feed maybe 2 or 3 motors ) and as u pointed to the installers and equipment mfrs had a plan,each room has a small step-down from 277-24 volts for the stat. controller,to them its easier to buy motors from the states at only 5 or 6 at a time than to stock pile motors or even change out or add stuff.I guess thats y they are owners, managers and persons like me JUST workers.
RE: new guy on block asking question
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: new guy on block asking question
Can you get the motors with PTC thermistors in them? That way you could monitor actual motor temperature instead of current and get some advanced warning of impending failure. If you already have the motors, a local motor shop should be able to retrofit thermistors into them, then you just need a thermistor trip relay or a good solid state overload relay that accepts a thermistor input as well.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376