250v delta to 208v wye

[starkmanelectric]

I'm doing work at a building where there is an existing 120/240 delta w/ hi leg system. The building now has the option to go 120/208 wye. This would be fine because they have very little 3-phase equipment and they are loosing 33% of their breaker spaces with the hi leg. My question; Will their existing equipment have problems? Most of their 2-pole single phase equip is rated for 240 volts. The only 3-phase unit that they have is rated for 230-volts. I don't see any multi-tap options on the motors. These are standard sanders and equipment that can be purchased at tool stores. Will this equipment run well on 208-volts without problems?

 

[bennie]

Re: 250v delta to 208v wye

The tools will perform OK if 200 volt rated

230 volt rating will be over a 10% departure from rated terminal voltage.

The tools will overheat, and have a reduced life expectancy.

 

[Ed MacLaren]

Re: 250v delta to 208v wye

Starkman, The 230 volt motors will draw approximately 10% more current when operated at 208 volts, but, like any motor, at any voltage, they will only overheat if the current exceeds the nameplate rating.

Another way of looking at it - at 208 volts, they will draw their rated current at about 90% of rated load, so if they are operated below 90% of full load, they should be OK.

Ed

 

[bennie]

Re: 250v delta to 208v wye

Please refer to NEMA Standard Publication MG-1-1993 copyright 1995 by NEMA.

 

[hurk27]

Re: 250v delta to 208v wye

Any equipment that has a high startup load will be affected. we had a truck shop that changed from 240/120 high-leg to 120/208 and they lost both of there air compressor motors within a week
and kept over heating the aircondtioner compressors but they were ok after installing buck/boost transformers on them but had to replace the motors on the air compressors.