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Thread: Need help with phase converter and switch

  1. #1

    Need help with phase converter and switch

    On a recent trip to Phoenix Arizona with my wife to visit some of her family one of her family members asked me if I would be interested in a shaper and a table saw. He once owned a furniture building business so I was pretty excited to see what he had. He had a Powermatic 72 industrial table saw and a Powermatic 26 shaper. I ended up buying them for a song and rented a Uhaul to drive them home.

    Just got back and got them unloaded and moved into my shop. Now I just noticed that they are both 3 phase. I would like to use two static phase converters that I have already purchased. I am ok with a 1/3 less power. The PM72 is a 7.5 horse and the PM26 is a 5 horse so loosing a third will still make a huge upgrade over my current 1.75 horse table saw and my router table. I already have a static phase converter rated for 7.5hp to something like 12hp and another one rated for 5hp to 8hp or so. I feel perfectly capable of hooking these up because I wired my entire shop by myself although I will likely have an electrician to either review my work or help with the install. I have several electrician friends that would be fine helping. What I am now trying to figure out is will the stock switches work to power the machines on and off or will I need to purchase some new magnetic switches or starters? I believe they are wired for 220v but I will have to verify. Assuming they are both wired to 220v will the existing stock switches work?

  2. #2
    Join Date
    May 2018
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    Lancaster, Ohio
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    need pictures

  3. #3
    Join Date
    Oct 2019
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    Whitehorse, Yukon
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    One of my table saws has a static phase converter on it, and it does still have the stock switch. It's an old Delta with 7.5 hp main and 3/4 hp scoring motors, and works just fine with the reduced output from the converter.
    I bought the saw with the static converter already installed, so I'm not sure about the schematics of the wiring, but it appears that it can definitely be done.
    Perhaps your static phase converter manual would have some information that can help guide you in hooking up your "new" machines.

  4. #4
    Looks like the pm72 has no switch. Great. This is turning out to be a bigger endeavor than I anticipated. Would I be ok with a standard single phase magnetic switch matched to the horse power and wired to the spc?

  5. #5
    Join Date
    Aug 2015
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    N. Texas
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    Quote Originally Posted by Bobby Robbinett View Post
    Looks like the pm72 has no switch. Great. This is turning out to be a bigger endeavor than I anticipated. Would I be ok with a standard single phase magnetic switch matched to the horse power and wired to the spc?
    Do you mean "switch", as in ON/OFF switches that you lay hands on to start/stop? Or do you really mean "contactor"?

    From the way you phrased the question, I assume "contactor" - and short answer, no you can't.

    3-phase contactor (aka 3-pole switch) requires disconnecting 3 wires; 1-phase contactor (aka 2-pole switch) can only switch 2 wires.

    Either 3-pole or 2-pole may have various auxillary contacts that open or close with the main contacts, but 'aux' means they are NOT rated to carry the same amount of current as the mains. Aux contacts are used for control and monitoring purposes.
    Molann an obair an saor.

    If Heaven ain't alot like Texas, I don't wanna go. - Hank Jr.

  6. #6
    Quote Originally Posted by Malcolm McLeod View Post
    Do you mean "switch", as in ON/OFF switches that you lay hands on to start/stop? Or do you really mean "contactor"?

    From the way you phrased the question, I assume "contactor" - and short answer, no you can't.

    3-phase contactor (aka 3-pole switch) requires disconnecting 3 wires; 1-phase contactor (aka 2-pole switch) can only switch 2 wires.

    Either 3-pole or 2-pole may have various auxillary contacts that open or close with the main contacts, but 'aux' means they are NOT rated to carry the same amount of current as the mains. Aux contacts are used for control and monitoring purposes.
    I mean on and off switch to turn the machine on and off. I was thinking that I could use a 220v single phase switch and have it in line on the circuit before the static phase converter, but I am not sure if it would be possible to find a 10 horse power switch? What would you suggest for turning the machine on and off?

  7. #7
    Does anyone have any input on getting some sort of switch to turn on and off my powermatic 72? I just got a static phase converter for it. It is a 7.5 horse power table saw but i bought it used and it did not come with the switch. Would I need a contactor or a switch specifically for a 7.5 horse motor? Would it need to be a three phase switch or could I place it online before the static phase converter and use a single phase switch? Sorry for all the questions. Just want to get this thing up and running.

  8. #8
    Join Date
    May 2014
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    Alberta
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    Hey Bobby you stated earlier in this thread that you had a couple of electrician friends that could help you. Now is the time to talk to them. This sounds to me like a situation that without being able to see the saw or pictures it is very hard to help you. At any rate an electrician will be able to answer all your questions at once. Good luck.

  9. #9
    I always cringe when I hear about using a static converter, single phasing a motor is not a good idea and with VFD's being more affordable making them a great choice in phase conversion, it does make it a bit more difficult when a motor is over 3 HP but still doable.

  10. #10
    Quote Originally Posted by Rollie Meyers View Post
    I always cringe when I hear about using a static converter, single phasing a motor is not a good idea and with VFD's being more affordable making them a great choice in phase conversion, it does make it a bit more difficult when a motor is over 3 HP but still doable.
    Trust me I would love to have a VFD on my PM72 but this is a 7.5hp saw and a VFD in that power category is more than I could likely sell the saw for. I have decided to get a static phase converter for now but will perhaps one day get a large RPC and add more 3 phase equipment. I already have the static phase converter and just want to get the saw operational for now.

  11. #11
    Looking at ordering a SquareD 8911dpsg 23v09 7.5hp 230v three phase magnetic motor starter. Amazon has them for under $150 shipped to my door. This is what my electrician suggested, I just wanted to confirm with you guys that this would be adequate and optimal.

  12. #12
    Join Date
    Aug 2015
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    Quote Originally Posted by Bobby Robbinett View Post
    Looking at ordering a SquareD 8911dpsg 23v09 7.5hp 230v three phase magnetic motor starter. Amazon has them for under $150 shipped to my door. This is what my electrician suggested, I just wanted to confirm with you guys that this would be adequate and optimal.
    Based on the part number, it certainly should handle nearly any 7-1/2 Hp motor at 230VAC. It does show to have a 230V coil, so that voltage will pass thru the Start/Stop operators (pushbuttons), but this is certainly common and workable. And, at least on Grainger site, the part number indicates it includes the O/L relay. = You should be all set on motor starter.

    I will stay out of the static converter discussion; its not in my wheelhouse.
    Last edited by Malcolm McLeod; Yesterday at 10:02 AM.
    Molann an obair an saor.

    If Heaven ain't alot like Texas, I don't wanna go. - Hank Jr.

  13. #13
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
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    3,639
    Consider adding another stop switch on the back end of the saw. I would buy a used motor starter with adjustable overloads for about 1/4 of that price from the bay. Just make sure you like the coil voltage before buying. Do you also need to buy a stop/start control station? get a mushroom "off" switch to fit. Lighted red is nice.
    Bil lD

  14. Quote Originally Posted by Bill Dufour View Post
    Consider adding another stop switch on the back end of the saw. I would buy a used motor starter with adjustable overloads for about 1/4 of that price from the bay. Just make sure you like the coil voltage before buying. Do you also need to buy a stop/start control station? get a mushroom "off" switch to fit. Lighted red is nice.
    Bil lD
    Yes I will need a start/stop button to power the saw on and off. I am not well versed in this stuff so buying a used starter off eBay and having to adjust overloads and knowing what to look for with regards to coil voltages is not something that I feel comfortable doing. Now granted, if someone wants to explain these things to me and help me understand this stuff I would be all ears. I have just noticed that any time someone is asking basic questions about this stuff the group on this board seems to get pretty defensive.

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