Converting 250V 3phase to 208V 3 phase

[tbob]

I need your help! I sell restaurant equipment at work. I have a customer who wants to buy a used 208V 3phase chicken pressure fryer from us. When you measure across two of the three phases she has in her place you get a reading of 252 Volts. If we hook up the unit "as is" it will eventualy burn up the elements.
As I see it we have two options:


Find her a another 240V unit
Find a transformer to "step" down the power from 240 to 208


Do they make such an animal?
Thanks, Terry
P.S. It draws about 41 amps on each leg

[hidollartoys]

You should check with the power co to determine exactly what voltage they are supplying. If it actually 240v then check with the equipment mfg'r to see if that particular fryer can operate on 240v. If the supply voltage is 240v and the equipment requires only 208v then you can install a stepdown transformer. Since you are in KC you should check with Industrial Surplus @816-920-7077. NO I dont worl there or have ANY connection, Just know they exist.

[Stuart in MN]

Yes, a 240:208 stepdown transformer is a common item. Any local electrical supply house should be able to get you one. Also, check to see if the fryer is rated for use at either voltage and/or can be rewired for 208 before you go further, many devices have that capability. It should be marked on the nameplate on the back, or contact the manufacturer (you may be able to go to their website and find specifications and installation instructions.)

[tbob]

Thanks for the input guys. Power was checked by electrician. It's going to Hiawatha, Ks, which is about 1.5 hours away from KC. We try to cut down on service calls by getting it right the first time. The unit is specific for 208. I'll see if I can get a transformer here in KC. Is this called a KVa?

Thanks again, Terry

[hidollartoys]

KVA is the capacity rating for transformers. Your application will require a 10 KVA transformer. KVA is "Kilovolt ampere" For 41 amps @208 volts ...... 208 x 41/1000 = 8.52 KVA. Supply the amp draw and the voltage to your transformer supplier and they will size the transformer accordingly.

[W-Cummins]

You need to use buck/boost transformers (an autotransformer) in the buck mode. They are made for just this application and are cost effective.

William...

[Torque1st]

Again, check with the local utility company for the service specs at the intended location. It looks like the electrician is measuring the "wild leg" which can vary with loading. Get your information correct before you spend $$ on a transformer and multiple service calls to get the job done right.

[W-Cummins]

When you measure across two of the three phases she has in her place you get a reading of 252 Volts.

Sounds like a Normal 240V service to me ( it's a little hot but within 5%) My 480 service is also slightly hot at 498-500v. I think the local guys run it hot here to allow for a heavy load pulling it down at times of high demand...

Again, check with the local utility company for the service specs at the intended location. It looks like the electrician is measuring the "wild leg" which can vary with loading.

No, it dose not look like a wild leg measurement at all, he said it was measured between the hots, The wild leg "measurement" is from a hot, to the grounded conductor if present, or the equipment ground if not ( in the case of no grounded conductor the wild leg is not a problem as you are not to use the equipment ground as a return path.

William....