Just looked at a large parts washer at one of the industrial facilities we work at that they want to install. The existing service is 480/277v The machine draws 280 Amps at 230 volts according to the name plate. I need to put a transformer in for the 208/120v loads in the area already. My question is, is there some way to avoid having to put in two separate xfrmrs? I am thinking I can't get a buck boost that big. It seems the only solution is to install a xfrmr to service the 208 and , and another one for the equipment. Am I missing something? :?
Need advice for 230V Equipment on 208Y Service
- Thread starter ccrtech
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skeshesh
Senior Member
- Location
- Los Angeles, Ca
Assuming the nameplate states nothing about 208V I'd give a call to the Mfg to find out. Most electrical equipment will tolerate a -10% so if it is indeed rated at 230V it will operate at around 207V but voltage drop and fluctuations in voltage are definitely going to be a problem in that case. Some Mfg. do put 208/230 or some mention of operation at 208V on their nameplates, but I've encountered some units in the past where the Mfg. confirmed in writing will work on 208V and it was not stated or the plate was not legible.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
I don't often come across "230 volts" in a three phase system. I do see 240 volt, single phase, distribution systems supplying motors rated at 230 volts, single phase. What does the nameplate say about the number of phases?
In answer to your question, if the manufacturer has not dual-rated the equipment for 208/230 volts, then either you need to find a buck/boost that has sufficient capacity to handle your load, or you need a separate transformer.
In answer to your question, if the manufacturer has not dual-rated the equipment for 208/230 volts, then either you need to find a buck/boost that has sufficient capacity to handle your load, or you need a separate transformer.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
This is correct. But as a gross general rule, if the machine was made here in the US using new NEMA design motors, it will tolerate the 208V input just fine. Typically what they do is use a motor designed as 220V 60Hz and the +-10% covers 198 to 242V supplies.
If it was made overseas using IEC motors, it will not. They don't have 208V as a standard and even the 230V rating they put on things was usually designed for 230V 50Hz, so if there was a fudge factor it has already been consumed just in the frequency change.
In the off-hand chance it was designed for use in Japan, you are back to it being OK, they do have 200V over there and they have both 50Hz and 60Hz, so they too design to cover a wider range.
Electric-Light
Senior Member
Separate transformer might not be a bad idea depending on the installation circumstance.
Unless the 208/120 transformer is substantially larger than 280A, you will have substantial flicker when that equipment kicks in assuming its a motor load.
Unless the 208/120 transformer is substantially larger than 280A, you will have substantial flicker when that equipment kicks in assuming its a motor load.
I spoke with someone at the manufacturer. They said it according to the serial # that it is actually gonna need 240. 300A at 240V 3 phase seems like such an uncommon motor size. The person I spoke with at the company said that they built very few at 208 v 3 phase, and built quite a few in 240 V . It's looking more and more like a additional transformer.
Electric-Light
Senior Member
230v is a fairly common rating for motors, but 300A? It sounds like the motor is 100hp or more. Is there a way to wire it for 480v?
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
If most of the load is a single motor it might be cheaper to just replace that motor with a 480V motor rather than try and get a 300A 3 phase Xfmr.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Might end up being the easiest solution. You will lose about 20% of the heat at 208 versus 230. I am kind of amazed that they did not order the right voltage to begin with.
There are 51 KW of heaters in the unit. The unit was built here in the US. They had it in another facility in Florida and moved up here. I even spoke to the guy who disconnected it at the old plant and he couldn't remember the voltage of the panel he took it out of but said there was no special transformer for it.
Electric-Light
Senior Member
Well, if you run heaters meant for 240v on 208v, they simply run at 75% power.
Most ranges and water heaters are rated 208 and 240, but with separate wattage ratings. The adverse effect is reduced output.
Most ranges and water heaters are rated 208 and 240, but with separate wattage ratings. The adverse effect is reduced output.
stew
Senior Member
- Location
- federal way,washington
Remember with a boost and buck you are only boosting the ratio between the input voltage and the output voltage. Its is only a roughly 10% boost so you would not need a very large boost transformer. a pair of 12.5 kw transformers should work nicely. you are only boosting the resultant difference in kw not the whole load using an autotransformer hookup
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stew
Senior Member
- Location
- federal way,washington
not sure what j raef is alluding to when he states that motors in the US are designed around 220v. The standard nameplate voltage in the US is 230/460 not 220. 220 50 cycle motors will run fine on 230 volt 60 cycle as well.
kwired
Electron manager
- Location
- NE Nebraska
They will run at a faster speed. 208-230/460 is a common nameplate voltage also.
He was saying that the design voltage for motors rated @ 208 - 230V was 220V.
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