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Mike G.
Mike G., Master Electrician
Category: Electrical
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Experience:  Proven Professional 48 years Experience
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I have a 3 phase 212 power running to a machine with a 50 mz

Customer Question

I have a 3 phase 212 power running to a machine with a 50 mz 220 motor. I've never had problems TJ jnh motors like this before, but the service tech for the company says I MUST have 220 volts for this Chinese motor because it doesn't have the tolerances of most motors. He recommends that I put a step up transformer on only two lines. Don't I need it on all three lines.
Submitted: 5 months ago.
Category: Electrical
Expert:  Mike G. replied 5 months ago.

Hi, I'm Mike and I'll be assisting you. Please stand by while I review your question.

Expert:  Mike G. replied 5 months ago.

Only 2 boost transformers are required. To select and see how to wire go to Hammond Power Solutions online PDF

Customer: replied 5 months ago.
even though all lines are 212 I only need to boost 2 of them? The wood shop next door has all of their machines connected via 3 boosters. Why would they do this?
Expert:  Mike G. replied 5 months ago.

All I can say is that you only need 2. Why others have 3, I can't say. Go to the PDF suggested for the info.

Expert:  Mike G. replied 5 months ago.

One more thing. I would think that the motor being 50hz and our electric being 60hz would cause a problem.

Customer: replied 5 months ago.
The tech said by boosting to 230-240 that it would make up for it…
Customer: replied 5 months ago.
The motor runs a hydraulic pump. FYI, I know that on several on an old French motors 50mz (c1960s) that also run pumps, they run fine on 60mz even though the motors do NOT say 50/60mz.
Expert:  Mike G. replied 5 months ago.

Only wanted to bring it to your attention.

Expert:  Mike G. replied 5 months ago.

Might want to check out "" for a take on motor burn out with use of different Hz.

Customer: replied 5 months ago.
I appreciate it. The electronics on the machine run into two large inverters and then into mostly DC relays. i will take a look at the smaller motor on the saw and look at the website you provided.So to confirm. 4 pole, 3 phase motor needing 220/240. Choose two of the three 208 main lines running from my disconnect and connect the two step up transformers. The third runs directly into the machine w/out a transformer.
Expert:  Mike G. replied 5 months ago.

The equipment I gave was a buck boost transformer not a single 3 phase transformer. You may use either.

Customer: replied 5 months ago.
Sorry for the delay. Getting in contact with the manufacturer in china and then an engineer that was well spoke in in English was more difficult than expected. I also thought I had responded to you earlier w letttjng you know I was contacting the manufacturer. I can't find a record of that. Sorry for the confusion.Based on the conversation with the engineer he said that due to the "exacting" requirements needed to use the hydraulics pump as a heavy duty "step motor," the small drop in pump pressure by not powering all 3 phases might not permit precise positioning of the table, or the saw and router arms.So I guess my last question to you is, when I wire each phase:
1. Where does the neutral 4th wire go?
2. I need a ground going to each transformer along with on of the phase wires. Correct?
Expert:  Mike G. replied 5 months ago.

The motor will either have designated terminations or wire colors as shown on the wiring diagram

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