If a motor is three phase 208 there is no way your going to get it to work on 240 single phase.I believe this is the only problem you would encounter..motors. If they are 3 phase they can't be used at all on a 120/240 system, unless u have a phase converter. But it would be cheaper to buy a motor.
Re: 208/230v can run off 240?#72153 11/20/0611:11 PM11/20/0611:11 PM
Electure, thanks for that clarification. I usually let it pass, the general population probably keep referring to it as 110/220, but in my experience, the only 110 I have encountered was in a tiny 7.2 KV:110 pot(1 kVA) feeding a control circuit operating a 12,470 capacitor bank.
Most of the time I run into high voltages i.e., 123-127 volts. I get to sell a lot of 130 volt bulbs
Re: 208/230v can run off 240?#72155 11/23/0603:02 PM11/23/0603:02 PM
Let's not confuse what the PoCo provides with what is stamped on the nameplate.
I have seen all sorts of markings on equipment. Some of this is a creation of testing methods.
For example, NEMA standards expect motoes to work within 10% of the nameplate markings. So- - a motor marked "240" would be tested at 216 volts as well as 264 volts; - a motor markes "208" wuld be tested at 187 and 229 volts; - a motor marked "208/240" would be tested over the entire range of 187 to 264 volts (with re-wiring as appropriate); and...
- a motor marked "220" would be tested at 198 and 242 volts.
I set the last one apart, because by having such a rating, a motor could be made to serve both 208 and 240 volt systems, without the need for multiple taps.
In short, the nameplate rating is completely separate from the nominal voltages of the power grid.
Re: 208/230v can run off 240?#72156 11/23/0604:08 PM11/23/0604:08 PM
That's a slightly different thing, they raised the nominal grid voltage from 220/380V to 230/400V, each +/-10% tolerance. Some people say old 380V motors tend to burn up if they're connected to a new transformer that provides a higher voltage.
Re: 208/230v can run off 240?#72158 11/24/0603:04 PM11/24/0603:04 PM
Almost all of the motors we hook up out where I work are 9 or 12 lead, 230/460V 3phase... Although unless it's way off in some corner of the lease, the 480V network tends to run about 492V phase to phase, ungrounded delta.We've never had a problem with motors biting the dust that I've seen. (Largest motor I've connected was 250 HP. @ 1400 rpm. The 800A MCC rattled louder than that motor on startup ) Controls and buildings feed from "PanelTrans" that output 120/240V single phase.. We usually put these a tap lower on the primary connection and get a nice 121/243V output.