I hooked up a 208/240v commercial microwave over to my system, I made the outlet today. The microwave has a voltage selector on it. When I measure it, it shows 209-211v constantly going up and down on a volt metter. Should I be running my microwave on 208V mode, or 240V mode?
Definitely 208.
-- Tom H
Generally, by historic "treaty," 208V appliances are intended to operate OK on about 191-218V... er, not catch fire anyway.
?s falke
"buildmorel> I hooked up a 208/240v commercial microwave over to my system, I made
| I hooked up a 208/240v commercial microwave over to my system, I made | the outlet today. The microwave has a voltage selector on it. When I | measure it, it shows 209-211v constantly going up and down on a volt | metter. Should I be running my microwave on 208V mode, or 240V mode?
I'd go with the 208 volt selection. If you have 3-phase power coming into the building, it's probably 208Y/120 and your outlet is wired for line-to-line voltage. Measure the line to neutral voltage and see if it is about 122. The ratio will be 1.732:1 if three phase.
Unlike some more agile devices like switching power supplies, which can be made to work through quite a wide voltage range (at the expense of having high harmonics), some things like lights and motors have more of a problem with wide voltage swings. I've seen 240 volt motors burn out on 208 volts.
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.