50hz motor in the us

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RLSIII
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50hz motor in the us

Thu Mar 10, 2016 9:02 am

Greetings all,
I have recently made the plunge into three phase equipment and acquired a 16" hammer jointer that requires 230v 50hz 3 phase. Along with a massive 7.5 HP 18" table saw and a monolithic Moak shaper. The table saw and shaper both use 60z 240 same as the power in my new shop, however I am unsure about what to do with the jointer. My Electrician wants to sell me a transformer to give me 50hz but other woodworkers have told me the motor will just run cooler and 20% faster. Anyone have any experience with such a situation. It's the only machine that I own that runs on 50hz so I'm tempted to try and save a grand if the jointer will be ok. Am I way off base here?

Thoughts are much appreciated,
Rob Shearer
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Chris Hall
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Re: 50hz motor in the us

Thu Mar 10, 2016 9:45 pm

I have experience with this exact situation. 50 hz will work fine on 60hz, at 20% faster, but....

...the ideal is to have the voltage/frequency ratio kept the same.

A typical German machine is 380v, 50hz, a voltage/hz ratio of 7.6:1

If you wish to supply 60hz to the same machine, and keep to the same ratio, then 60 x 7.6 = 456volts.

Similarly, 230v, 50 hz. is a ratio of 4.6:1. At 60hz, you would ideally want (60hz x 4.6) a 276v. supply. That's the basic principle.

If you do not adhere to the voltage/hz ratio, then the motor will still operate, but flux losses will accrue inside the motor - ionic loss from either the copper or the iron portion, which over time will eventually damage the motor. A jointer does not run all day, so you would likely not notice anything for a very long time however.

It is worth your while to get a transformer I think, to end any apprehensions you may feel. I paid $800 for a transformer (a supplier up in Canada I can refer you to if you are interested), stepping up my utility feed of 208v/60hz, and outputting at 456v/60, which works perfectly with my German milling machine. My saw is English, and rated at 415v/50hz. but that is close enough, ratio-wise, to make use of the same transformer.
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RLSIII
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Re: 50hz motor in the us

Fri Mar 11, 2016 8:19 am

Electronics bewilder me. It seems logical, however as an outsider looking in; it is daunting. I would very much appreciate the Canadian manufacturer you recommend. Odly enough that the exact price the Electrician quoted me (uninstalled) I wonder if it's the same unit. Some part of me knew the transformer was the way to go, but I feel much better about the cost understanding the long term implications of the choice at hand.
The factory I'm in used to be an aluminum forge so the whole place is wired for 240 3ph on a 600amp service (in my 3000sq' area) some with open air bus bars. Quite an intimidating set of lines open in the ceiling like that apparently even for a commercial Electrician. The plan so far is to run new line from the service main to a panel all my own bypassing all of the existing lines. Apparently the building I'm in has no neutral lines so I need a device(cant recall the name) that effectively generates a neutral for my 110 power. It's been a learning experience, costly as well, but I think it will be worth it to have room to expand down the line.
Il post pictures of the setup to follow as it develops. Thank you for the insight.
Rob S
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Chris Hall
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Re: 50hz motor in the us

Fri Mar 11, 2016 9:03 am

The good thing is you are dealing with electrics, not electronics, so it is all supposed to be a lot simpler, hah, hah.

The transformer I purchased came from:

Marcus Transformer of Canada
Suite 26
999 Du College Street
Montreal, Quebec h4c 2s3
Aram Essagian 1-800-276-7673
aram@marcustransformer.com

I picked a 15kva model, but my situation is slightly different than yours.

According the the NEC, a transformer is considered akin to a separate electrical service in a building, and thus must be set up in the same manner as a service entrance. That means you must create proper grounding for it - if you are in a metal frame building this will be very simple to solve. In other cases, you will likely be tying onto the water line where it comes out of the soil.

As for the neutral, the machines you have probably do not have internal provision for neutral anyhow, but if so, neutral will connect to the grounding conductor at some point, just as is done at the load center. In my set up, I connected the neutral in the transformer to the ground. You'll want to quiz your electrician about this and make sure he knows his stuff in this regard. The guy who gave my set up a look-over, though a recently-qualified electrician, really didn't know his stuff, as I found out later on from other helpful folks (who were also electricians).

I imagine you would want to bring the power over to a load center, and then establish a branch circuit to the transformer. From the transformer you will need service disconnects for each machine, or another load center. The separate service disconnects are the way to go unless you have more than 6 machines, and you can put the disconnect near each machine as well.

You will be running a 3-phase dust collection system as well I presume?
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RLSIII
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Re: 50hz motor in the us

Sat Mar 12, 2016 12:26 am

Ahh electrics .
Unfortunately no I will not be running 3 phase dust collection just yet but I want to leave room for expansion. There is however a 20' tall 3 phase baghouse in the next room but it wouldn't fit in my area and is currently some 250 linear ft away. Not to mention it must weigh as much as a truck were i to try to move it. It was part of the forge circa 1950 and I am not sure if it is designed for wood anyway.
It is indeed a steel frame building, that is how the current 110 electric neutral is routed (to the frame/ground). From what I've gathered, with the exception of the jointer hz issue, my 3 phase equipment is plug and play. What you are describing sounds much the same as what the Electrician has suggested. I am currently awaiting a written estimate with some breakout lighting options.
Rob S
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Re: 50hz motor in the us

Sun Mar 25, 2018 3:25 pm

Richard,

so how did this situation resolve for you?

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