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Panel for phase converter

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Forum topic by SweetTea posted 08-17-2019 01:55 PM 187 views 0 times favorited 6 replies Add to Favorites Watch
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SweetTea

451 posts in 1138 days


08-17-2019 01:55 PM

Could use some help here guys. I have a 25hp 3 phase motor that I want to make into a phase converter. I just need to find someone that can build me a panel for it. The 3 phase motor also has a 2hp single phase “pony” motor attached located above in sort of a cage like thing that the previous owner used as his phase converter. Only thing is that when he sold it to me he kept the panel.

Are there any electrical gurus on this board that could build me a panel? Or can anyone suggest a person that I could contact and pay for this?

I considered building one myself but I don’t really feel like I could do it properly without someone holding my hand. American Rotary will ship a panel to my door for $588. Just trying to work on a a bit of a smaller budget. Still have to purchase a 100amp breaker, lots of wire, plugs, outlets, boxes, ect.

Anyone have any suggestions?


6 replies so far

View GR8HUNTER's profile

GR8HUNTER

6369 posts in 1191 days


#1 posted 08-17-2019 04:19 PM

go to the guy you bought stuff from ask if you can diagram his set up then take notes and pictures :<))))

-- Tony---- Reinholds,Pa.------ REMEMBER TO ALWAYS HAVE FUN

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SweetTea

451 posts in 1138 days


#2 posted 08-18-2019 09:46 AM



go to the guy you bought stuff from ask if you can diagram his set up then take notes and pictures :<))))

- GR8HUNTER

Unfortunately he live 6 hours away from me, plus he works nights and sleeps all day which makes it hard for me to get in touch with him.

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SweetTea

451 posts in 1138 days


#3 posted 08-18-2019 09:51 AM

I have somewhat of an understand on how to make the panel myself. Might actually try it. I know that compactors are used to balance the voltages across all 3 legs. I understand how that works and how to wire the compactors. I am sure that I could figure out how to wire the switch and such. The main thing that I don’t get is how to know what the voltages should be across all three legs? Do you just play around with the caps until they are all somewhat close? Or is there a specific way to calculate the ideal voltage?

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SweetTea

451 posts in 1138 days


#4 posted 08-18-2019 01:26 PM

I might try building one myself if I can’t end up finding anyone to build one for me.

With that said, why is it that on some of the build videos on YouTube, some people measure and balance the voltages across all 3 legs and other people just skip that part and let the voltages fall where they may?

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SweetTea

451 posts in 1138 days


#5 posted 08-18-2019 01:28 PM



I might try building one myself if I can’t end up finding anyone to build one for me.

With that said, why is it that on some of the build videos on YouTube, some people measure and balance the voltages across all 3 legs and other people just skip that part and let the voltages fall where they may?

- SweetTea

Is it necessary to balance the voltages if only running a wide belt sander? I could see doing it for a CNC but my RPC will only be powering my 10HP wide belt.

View CaptainKlutz's profile

CaptainKlutz

1748 posts in 1973 days


#6 posted 08-18-2019 03:32 PM

hmm,
Since you appear to already be searching internet for videos and help, not sure what more to add via a wood working forum?
The electrical focused forums cover line balancing in various levels of detail? Folks over at Practical Machinist site have plans for different types of 3 phase convertors, with balancing instructions.
Search for Fitch phase convertor.

FWIW – Unbalanced line voltages are not good, and will reduce total available power. Unbalance line currents will also require that balancing current to flow through the neutral line. Having different voltage value on each end of neutral line intentionally is not good design.

Unbalanced voltages put more stress on motor, and cause premature failure. Heavily loaded motors are usually more sensitive to line balancing than lightly loaded motors; but neither will be happy unbalanced. You can never really know how much an unbalanced line reduces motor life, until you buy a couple replacement motors. Motors can last 50 years properly serviced. Buying several new 10HP motors every couple of years is an expensive way to learn about unbalanced line voltages?
This might help: https://www.elongo.com/pdfs/voltages.PDF

May not be obvious without formal training, but when you use capacitors to balance voltages you are actually shifting the phase angle of the AC waveform. Balancing AC phase electrical power can be complicated. If you want to really understand what is happening, try reading this 300 level college class material.
https://pdhonline.com/courses/e336/e336content.pdf

Bottom line:
Can you live with out balanced voltages? Yes.
But if you want to tools to have best motor reliability, and reduced maintenance costs; balanced power is preferred.

#IAMAKLUTZ, not an expert.

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

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