8 Machines from China (380V/3P) - Can I run them on ONE transformer/circuit?

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BMS-Electrician

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Customer is setting up a new manufacturing facility with 8 Chinese machines. They all have internal breakers and are all 380V/3P/4W on the nameplate. The largest is 6kw and the smallest .5kw. total kw of all machines is 21.6. (machines are mostly cutting/drilling for making indoor window shutters). Main panel (400A 460V) is about 120' to the nearest machine and 250 to the farthest machine.

Do I need to run separate circuit to each machine (sub panel near machines) and install buck-boost at each machine or is there a more cost effective way to go about this?

Can I run one circuit through a 1.5kva buck-boost set up and split it to all machines?
 
First question- will they run on 60Hz?
Most effective is to get 480v 60Hz machines :LOL:. After that you're probably best off with a 480D to 380y transformer and a dedicated and well-marked panel near most of the machines. Also, if the machines actually use the neutral, then you need three buck transformers anyway.

There have been a lot of questions on MH asking this sort of question (380v equipment), searching them out will be time well spent.
 
Customer had a good-sized Carrier chiller that they brought in from Germany along with the machine the chilled water was used for. All that stuff was 380volt, don't remember the Hz but I think they ran it on 60 hz.

I think they spent more on the install than if they had just bought USA equipment
 
Customer made the mistake when he ordered, could have ordered 480.

@zbang, I appreciate the response, I guess my question was more about the idea of running multiple machines on one circuit. Can that be done (and still be code)? If I understand correctly, as long as I size circuit and wires for 125% of the largest load plus the sum of additional loads I should be fine. Am I missing anything here?

I personally think the best install is to buck boost each machine (they all require neutral) and install a sub panel with individual 15A circuits but we are looking at 10k just to buy the buck boost transformers so I wanted to know if there was a more cost effective option before I present this to the customer.
 

3-Phase 480V Delta - 380 Y 220​

SKU # MIT-DRY-146
NEW: $2,499
(You should be able to get a 480-380v 3-ph autotransformer for less than that; google is your friend.)

Whether you can, it's not a good idea to put them all on one circuit. If nothing else, you still need maintenance disconnects and might run into issues where the wiring in the smaller machine needs to be protected at a lower lever than the larger ones.
 
zbang said:
First question- will they run on 60Hz?
Most effective is to get 480v 60Hz machines :LOL:. After that you're probably best off with a 480D to 380y transformer and a dedicated and well-marked panel near most of the machines. Also, if the machines actually use the neutral, then you need three buck transformers anyway.

There have been a lot of questions on MH asking this sort of question (380v equipment), searching them out will be time well spent.
Click to expand...
I wonder if BMS knows that China is 50Hz?
 
@Besoeker3, no, I did not know that China was 50Hz. Does this mean I should be considering a frequency converter? The machines all have PLC controllers in them and many are titled "CNC" although the controls appear to be relatively simple.
 
BMS-Electrician said:
Does this mean I should be considering a frequency converter?
Click to expand...
Not necessarily*, but it does mean you'll either need to ask the manufacturer about 60Hz operation (start there!!, then read any install manuals there are; may have to search for them) or to spend a lot more time looking at them. Among other things-
Heaters won't care about the freq.
Line-supplied motors will run 20% faster. VFD-supplied motors won't, but will the VFDs accept 60Hz?
The PLCs might accept 60Hz but might not.
Other controls probably won't mind 60Hz but that should be confirmed.
(Basically, every component needs to be checked to see if they'll be OK.)

Could be that everything will already work on 480v 60Hz.... could be that all you need is that transformer, could be that you need that plus swapping a power supply or something, could be the mfg says DON'T DO IT. Another consideration, just to scare people, is that any of this could void warranties and support.)

*Frequency converters are their own thing, and may or may not be suitable for this application. Could certainly call a couple of companies and ask them.

IMNSHO, non-North-American-market machinery is seldom worth the price, since the cost to install goes up quite a lot; much of the world is 50Hz and uses different voltages.

JoeStillman said:
Could you feed them all from a 30 HP VFD?
Click to expand...
Not directly- way too many harmonics and the VDF probably wouldn't like it, either.
 
BMS-Electrician said:
@Besoeker3, no, I did not know that China was 50Hz. Does this mean I should be considering a frequency converter? The machines all have PLC controllers in them and many are titled "CNC" although the controls appear to be relatively simple.
Click to expand...
CNC is Computer Numerical Control. I suppose that you could use a frequency converter. I don't how much that .would cost. As JoeS has said a VSD could be the answer but you need to look at what the machinery is being used for.
 
BMS-Electrician said:
Customer made the mistake when he ordered, could have ordered 480.
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If they could have ordered 480V/60Hz machines, is the following viable? Check with the manufacturer on what parts are different, order those parts, make the changes to the equipment. Or perhaps the lead time is prohibitive?

Cheers, Wayne
 
Speaking to the Manufacturer is a great idea. I will try. The challenge is that they don't speak English! However, my customer (who knows zero about electrical) does. So I will try that route and hopefully we can get some answers from the manufacturer.
 
BMS-Electrician said:
@Besoeker3, no, I did not know that China was 50Hz. Does this mean I should be considering a frequency converter? The machines all have PLC controllers in them and many are titled "CNC" although the controls appear to be relatively simple.
Click to expand...
Your mentioning of 380 volts in the OP was kind of a thing that triggers this assumption. Most the time equipment designed for that voltage is also designed for 50 Hz.

for an induction motor connected directly to an AC supply frequency is a big factor in the speed of that motor. As mentioned a 50 Hz motor with 60 Hz applied will run 20% faster RPM. This generally means it will also be loaded more if connected to same output with no other changes. With centrifugal fans and pumps that load increases with speed exponentially - this actually can cause overloading conditions for those motors in many cases if something isn't done to compensate for the higher speed.
 
petersonra said:
There's no reason why you can't run all the machines off the same transformer bank. It might be inconvenient but it could be done.
Click to expand...
They each likely need to be on their own branch circuit though there is more than one way to do that.

A feeder then feeder taps to each branch circuit is electrically the same thing as a panelboard with a branch circuit to each machine, just not as condensed.
 
BMS-Electrician said:
Speaking to the Manufacturer is a great idea. I will try. The challenge is that they don't speak English! However, my customer (who knows zero about electrical) does. So I will try that route and hopefully we can get some answers from the manufacturer.
Click to expand...

As mentioned, communicating with the manufacturer to determine if the equipment can be run on 60 Hz should be a top priority.
It should also be asked what voltage would be best if the equipment was run at 60 Hz. Because motor windings are inductive the current will go down at higher frequencies, which is why VFD's are often run on a V/Hz basis. But there will be a maximum voltage allowable because of control circuit limitations, insulation ratings, etc.
 
See if you can get specs and drawings on the machines so that you can evaluate what is inside. As the others have said, what you are powering makes all the difference in the world. Electronic power supplies, VFDs and Servos generally do not care what the line frequency is, because they just rectify it to DC anyway. Resistance heaters are insensitive to frequency. But motors and anything with an electromagnetic coil WILL be a problem. As mentioned earlier, AC motors (not on a VFD) will spin 20% faster, but also feeding 60Hz to a contactor coil that is designed for 50Hz can over heat the coil and cause it to fail in short order. Also, in a lot of cases where machines are designed for 380V, the controls are sometimes derived from a connection between Line and Neutral, which is 220V. So whatever you use to convert to 380V must be 380V with a grounded Wye point as a Neutral. That makes it complicated to just use Buck-Boost transformers.

You really cannot make any determination on the right approach without knowing a lot more details about the machines in question. Yes, it sucks that your customer made this mistake, but to be honest, the SUPPLIER, knowing that they were shipping to the US, should have let them know too.

A bargain is not always a bargain. You get what you pay for...
 
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tom baker said:
Is this equipment UL listed?
In WA it would have to be listed or have an engineering evaluation.
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I would place this high on my question list. ()probably as #1) OSHA and/or your local jurisdiction could throw a wrench in the entire install if the equipment is not UL or other APPROVED NRTL listed.
 
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