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Need help with wiring for a Powermatic 72

2K views 21 replies 5 participants last post by  SweetTea 
#1 · (Edited by Moderator)
I have a 3 phase 7.5hp Powermatic 72 that I am getting ready to run the line for getting power to it. I have a RPC that is driven by a 25hp motor. The only thing is that the Powermatic 72 is wired for 440v. Would I need to change the wiring over to 240v before connecting it to my RPC? If so, is this done at the switch? Star/Delta type thing? I have an industrial electrician coming to run my lines. I am sure he is more than capable of switching it over. I am just curious. I am using 10/3 mc for the wiring and running it on a 40amp 3 pole breaker at my load center.
 
#2 ·
7 1)2 HP should draw 22 amps on 230/240 volt system 10 awg is good, but code shows a 45 amp breaker, and the proper heater element overloads in the starter. Just a switch or disconnect to turn it on or off without overload protection will not protect the wire and can be dangerous. Many people do not want to spend the money for a starter, but without a starter you need to put 10 awg on a 30 amp breaker, no larger. Or upgrade to 8 awg wire. And don't forget the ground wire, 10 awg, not 12 or 14. Rotation is changed at the motor connection box, the diagram is on the motor.
 
#3 ·
... Powermatic 72 is wired for 440v. Would I need to change the wiring over to 240v before connecting it to my RPC?
Yes. (Well, actually it only has to be done before you turn it on but you eliminate a chance for error if it's done first.)
.. is this done at the switch?
No, it's done at the motor.
Star/Delta type thing?
No, more like a series/parallel type of thing. There should be a wiring diagram on the motor or inside the connection cover that shows the proper way to do it.

The more difficult problem may be the switch. Assuming it's actually a contactor with overload protection there are two things to look out for.

First, the contactor coil voltage. If it's 480V it will need to be replaced. If it's low voltage with a transformer the transformer will need it's primary changed to 240V.

Second, the overload sensing will need changed since the motor requires twice the current at 240V. You may need to change heaters or adjust the current setting depending on exactly what you have.
 
#4 ·
7 1)2 HP should draw 22 amps on 230/240 volt system 10 awg is good, but code shows a 45 amp breaker, and the proper heater element overloads in the starter. Just a switch or disconnect to turn it on or off without overload protection will not protect the wire and can be dangerous. Many people do not want to spend the money for a starter, but without a starter you need to put 10 awg on a 30 amp breaker, no larger. Or upgrade to 8 awg wire. And don t forget the ground wire, 10 awg, not 12 or 14. Rotation is changed at the motor connection box, the diagram is on the motor.

- ibewjon
Will take your advice into consideration. I am planning to use the stock switch that came on the saw from Powermatic.
 
#5 ·
Add on…I meant to say voltage motor runs on is changed at the motor box, and rotation can also be changed there. Does the switch operate a starter mounted on the saw? And yes, the coil voltage or transformer wiring is another thing you will have to deal with.
 
#6 ·
... Powermatic 72 is wired for 440v. Would I need to change the wiring over to 240v before connecting it to my RPC?
Yes. (Well, actually it only has to be done before you turn it on but you eliminate a chance for error if it s done first.)
.. is this done at the switch?
No, it s done at the motor.
Star/Delta type thing?
No, more like a series/parallel type of thing. There should be a wiring diagram on the motor or inside the connection cover that shows the proper way to do it.

The more difficult problem may be the switch. Assuming it s actually a contactor with overload protection there are two things to look out for.

First, the contactor coil voltage. If it s 480V it will need to be replaced. If it s low voltage with a transformer the transformer will need it s primary changed to 240V.

Second, the overload sensing will need changed since the motor requires twice the current at 240V. You may need to change heaters or adjust the current setting depending on exactly what you have.

- clagwell
Add on…I meant to say voltage motor runs on is changed at the motor box, and rotation can also be changed there. Does the switch operate a starter mounted on the saw? And yes, the coil voltage or transformer wiring is another thing you will have to deal with.

- ibewjon
Here are the pics of the stock Powermatic switch and cut off box.

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#7 ·
This could be a problem. I know the heater elements are too small as on 240 you draw twice the amps, so you need the proper size. I am going to guess that the coil is 480 since I do not see a control transformer to give you a 120 control voltage. Hopefully the 120 coil is still available. And the fuses in the disconnect will also need to be replaced. I can post code chart fuse size later. The 600 volt rating of the disconnect is ok, just get the proper time delay to match the rated voltage of the disconnect.
 
#9 ·
Force of habit. Any control voltage over 120 has not been used in many years. Any place we worked, we changed over to 120 for safety. Or add a 240/120 control transformer to use 120 control voltage. The deciding point is what starter coil is available. You may need a new starter, or a vfd instead of the rpc. Or use a separate 120 circut for controls. Yes, it can get complicated. But you will still need new coil, new heaters, and new fuses. A vfd may be less expensive, or not much more.
 
#11 ·
Force of habit. Any control voltage over 120 has not been used in many years. Any place we worked, we changed over to 120 for safety. Or add a 240/120 control transformer to use 120 control voltage. The deciding point is what starter coil is available. You may need a new starter, or a vfd instead of the rpc. Or use a separate 120 circut for controls. Yes, it can get complicated. But you will still need new coil, new heaters, and new fuses. A vfd may be less expensive, or not much more.

- ibewjon
This is quickly going over my head. I am not familiar with what the coil, heater and starter are with regards to my 72. Are these items in the switch components?

Would it still require these modifications if I used a static phase converter? Could I just mount a SPC on the side of the saw and use a toggle switch? I do have a SPC on hand that is rated to the appropriate HP rating on this saw and the loss of 1/3 power will not affect the intended usage of this setup.
 
#12 · (Edited by Moderator)
+1 on the above intelligent electrical posts. Let a dummy, dummy it up for you:

Bottom line:
4 things have to change to get from 440v to 220v, regardless of your 220v 3PH source (RPC or SPC).

- If you keep the fuses in disconnect box (which are not required with proper sized breaker in the circuit, and overload on motor starter), they have be doubled.

- The coil on the contactor/relay in motor starter needs to be changed

- The overload heaters in the motor starter also need to be changed.

- The motor wiring connections down at motor will need to change from series (440v) to parallel (220v) configuration.

The suggestions for using a VFD might be confusing, until you realize the VFD would use your 220V input and generate 440V to run the machine. There are even some VFD that will take single phase 220v and generate 440v 3PH.

Note1:
With VFD supplying 3PH 440v, possibly none of wiring on machine needs to change. But you would lose the VFD control capability, such as soft start, adjustable frequency, adjustable overload, etc.

Note2:
The old ITE/Gould/Telemecanique company no longer exists. Various brands where sold to other companies, and some parts are still available. Finding coil and heater parts will probably have to use NOS (new old stock). Due to costs for NOS parts, it might be cheaper to replace entire motor starter with new IEC motor starter, or use a 220v to 440v VFD.

I don't mess with 440v 3PH much any more.
Will leave this in hands of our resident electricians for help.

#IAMAKLUTZ and hope i got the summary right.

Best Luck.
 
#14 ·
If you don t know what the various parts are, it is time to hire professional help.
- ibewjon
+10

BTW - If I was making the conversion from 440v to 220v, this would be my plan:
- Remove the disconnect switch, not needed for 220v machine using a plug/receptacle power feed.

- Call Powermatic and price conversion parts for changing motor starter to go from 440v to 220v. Assuming its original OEM starter. If less than $100, buy parts. If more than $100, buy a new IEC starter like this one:
https://www.amazon.com/Big-Horn-18837-220-240-Volt-18-26-Amp/dp/B002LVUWIQ

- Reconfigure and rewire existing motor starter for twice the current & half voltage,
or install new starter.

- Rewire the motor connections to 220v.

Plug it in, check voltages with meter. The hit power button, and run the smoke test.

Reason: The 220v to 440v 7.5HP VFD is $400+.
If I already have RPC with 220v 3PH power, it is cheaper to get new starter, larger wire, and new plug/receptacle; then cost of adding the VFD.
Not having the 1PH to 3PH PRC/SPC, it would be cheaper to use VFD instead, and remove all the extra stuff.

Cheers!
 
#15 ·
If you don t know what the various parts are, it is time to hire professional help.
- ibewjon

+10

BTW - If I was making the conversion from 440v to 220v, this would be my plan:
- Remove the disconnect switch, not needed for 220v machine using a plug/receptacle power feed.

- Call Powermatic and price conversion parts for changing motor starter to go from 440v to 220v. Assuming its original OEM starter. If less than $100, buy parts. If more than $100, buy a new IEC starter like this one:
https://www.amazon.com/Big-Horn-18837-220-240-Volt-18-26-Amp/dp/B002LVUWIQ

- Reconfigure and rewire existing motor starter for twice the current & half voltage,
or install new starter.

- Rewire the motor connections to 220v.

Plug it in, check voltages with meter. The hit power button, and run the smoke test.

Reason: The 220v to 440v 7.5HP VFD is $400+.
If I already have RPC with 220v 3PH power, it is cheaper to get new starter, larger wire, and new plug/receptacle; then cost of adding the VFD.
Not having the 1PH to 3PH PRC/SPC, it would be cheaper to use VFD instead, and remove all the extra stuff.

Cheers!

- CaptainKlutz
So I can purchase that $74 starter and reconfigure the wiring at the motor end for parallel instead of series then just remove the disconnect box and be good to go? With all of the talk I was afraid this would get very expensive very fast. That is not actually too bad.

Oh and I do have a professional that will be doing the work. I just needed to have an understanding of what and how this would all be done.
 
#16 ·
Force of habit. Any control voltage over 120 has not been used in many years. Any place we worked, we changed over to 120 for safety. Or add a 240/120 control transformer to use 120 control voltage. The deciding point is what starter coil is available. You may need a new starter, or a vfd instead of the rpc. Or use a separate 120 circut for controls. Yes, it can get complicated. But you will still need new coil, new heaters, and new fuses. A vfd may be less expensive, or not much more.

- ibewjon
I priced a VFD from Jack Forsberg a while back and for him to make one capable of running a 7.5hp motor it would have cost $500 then $58 shipping. This will be significantly cheaper with replacing the starter, switching the motor connections to parallel and removing the disconnect box. So far I am $600 deep in my 3 phase setup. I already had a 25hp 3 phase motor and purchased an American Rotary panel. The industrial electrician that is doing the install for me is a close friend and is taking beer and pizza as payment for helping me with this.

I did seriously consider using VFD's. I have a lot of 3 phase machines now including a 10HP wide belt and a 10HP dust collector that I am not yet using. The price on a VFD capable of running my 10HP wide belt was $850 + $80 shipping from Canada. That was a bit steep considering how many other 3 phase machines that I have. I plan to purchase another larger RPC down the road. All together I have 10 machines and counting that are 3 phase. I just picked up 2 more 10HP dust collectors at a price that I couldn't refuse.
 
#17 · (Edited by Moderator)
snip..
I have a lot of 3 phase machines now including a 10HP wide belt and a 10HP dust collector that I am not yet using. The price on a VFD capable of running my 10HP wide belt was $850 + $80 shipping from Canada. That was a bit steep considering how many other 3 phase machines that I have. I plan to purchase another larger RPC down the road. All together I have 10 machines and counting that are 3 phase. I just picked up 2 more 10HP dust collectors at a price that I couldn't refuse.
- SweetTea
Hmm,

1) Sounds like you have a commercial shop? Good for you.
With all those tools, must a have several employees? What do you produce?
BTW - Curious:
Why are fishing in hobby wood working forums for low cost electrical advice as commercial mfg?
What does your insurance company think about your power supply wiring, are we giving the right advice?
Are you using a licensed bonded/insured electrician to ensure everything is built to code, passes installation permit inspections; to ensure building passes your annual commercial insurance inspection?
NVM, those are rhetorical questions. What you do is your business.

2) You can't be cheap with industrial power, unless you want to kill people.
Industrial tools require costly industrial power support, and there is no way to avoid this. Back when I used to buy/install millions of dollars in production equipment all around the world every year, we would estimate and plan for a minimum of $500 parts & $1000 in labor for every machine install. This covered only breakers, conduit, wiring, disconnect switches; I.E parts/labor for physical hookup at machine only. If we needed to run wires around plant, or add power conversion that was extra. Power conversion was budgeted at ~ $300 per motor HP for RPC install. These Industrial power installation costs have been nearly same for many decades; thanks to general cost reduction of electronics and increasing cost of copper. You can not hide from cost of industrial power when you buy & install tools.

3) Power is dangerous, if you don't understand it completely, don't touch it; and always let the licensed & trained professional keep you safe. You can get hurt very bad:
I helped installed my 1st 440v panel when I was still a kid, back in 60''s. In 70's, watched a older co-worker attempt to work on live 440v 3PH panel (as is commonly done when you can not shut down a building), when he slipped and dropped a screw driver across the main feed. Building had it's own 25Kv step down transformer, and there was no lack of feed power available. Result was instant lightning bolt, screw driver melted completely, and his outline was permanently etched in wall 25 feet behind him with liquid metal from the plasma discharge. He lost sight for a month, and had burns all over his head/chest. He recovered eye sight in one eye, and is only scarred on 1 side of his face years later. I was around the corner getting tools when it happened, or I would have been shocked, burned as I was usually standing next to him as his apprentice. Was gruesome education into danger of high voltage.

Why post this?
Your electrical questions and posts scare me. Every time you post, they seem intelligent, even use right words asking questions. But when kind folks on LJ offer advice to help you; your responses show you to be uneducated, possibly dangerous with electricity, and only looking for cheap way out.

Hence, Think it best to stop offering you electrical help, after one last suggestion.

Please find and use licensed/binded electrical company for your 3 phase high voltage building power.
If you have numerous machines in a working shop, you are subject to state/local laws. You need a master wiring plan with approved building permits, and professional staff; keeping you, your employees, and your property safe.

Best Luck with all industrial tools.
 
#19 ·
Add DEAD to that. +100 to captain. I started to offer help then realized it was same person asking for RPC panel advice awhile back. Sorry sweet, but you are too cheap to be safe. No home shop needs two or more 10 HP DC. Electricity is something you can not see, but can, will, and does kill you or others. I will be watching for who is asking electrical questions before I answer.
 
#20 ·
snip..
I have a lot of 3 phase machines now including a 10HP wide belt and a 10HP dust collector that I am not yet using. The price on a VFD capable of running my 10HP wide belt was $850 + $80 shipping from Canada. That was a bit steep considering how many other 3 phase machines that I have. I plan to purchase another larger RPC down the road. All together I have 10 machines and counting that are 3 phase. I just picked up 2 more 10HP dust collectors at a price that I couldn't refuse.
- SweetTea

Hmm,

1) Sounds like you have a commercial shop? Good for you.
With all those tools, must a have several employees? What do you produce?
BTW - Curious:
Why are fishing in hobby wood working forums for low cost electrical advice as commercial mfg?
What does your insurance company think about your power supply wiring, are we giving the right advice?
Are you using a licensed bonded/insured electrician to ensure everything is built to code, passes installation permit inspections; to ensure building passes your annual commercial insurance inspection?
NVM, those are rhetorical questions. What you do is your business.

2) You can t be cheap with industrial power, unless you want to kill people.
Industrial tools require costly industrial power support, and there is no way to avoid this. Back when I used to buy/install millions of dollars in production equipment all around the world every year, we would estimate and plan for a minimum of $500 parts & $1000 in labor for every machine install. This covered only breakers, conduit, wiring, disconnect switches; I.E parts/labor for physical hookup at machine only. If we needed to run wires around plant, or add power conversion that was extra. Power conversion was budgeted at ~ $300 per motor HP for RPC install. These Industrial power installation costs have been nearly same for many decades; thanks to general cost reduction of electronics and increasing cost of copper. You can not hide from cost of industrial power when you buy & install tools.

3) Power is dangerous, if you don t understand it completely, don t touch it; and always let the licensed & trained professional keep you safe. You can get hurt very bad:
I helped installed my 1st 440v panel when I was still a kid, back in 60 s. In 70 s, watched a older co-worker attempt to work on live 440v 3PH panel (as is commonly done when you can not shut down a building), when he slipped and dropped a screw driver across the main feed. Building had it s own 25Kv step down transformer, and there was no lack of feed power available. Result was instant lightning bolt, screw driver melted completely, and his outline was permanently etched in wall 25 feet behind him with liquid metal from the plasma discharge. He lost sight for a month, and had burns all over his head/chest. He recovered eye sight in one eye, and is only scarred on 1 side of his face years later. I was around the corner getting tools when it happened, or I would have been shocked, burned as I was usually standing next to him as his apprentice. Was gruesome education into danger of high voltage.

Why post this?
Your electrical questions and posts scare me. Every time you post, they seem intelligent, even use right words asking questions. But when kind folks on LJ offer advice to help you; your responses show you to be uneducated, possibly dangerous with electricity, and only looking for cheap way out.

Hence, Think it best to stop offering you electrical help, after one last suggestion.

Please find and use licensed/binded electrical company for your 3 phase high voltage building power.
If you have numerous machines in a working shop, you are subject to state/local laws. You need a master wiring plan with approved building permits, and professional staff; keeping you, your employees, and your property safe.

Best Luck with all industrial tools.

- CaptainKlutz
Did you even read my other post? You seem to be reading into things and making assumptions about stuff that I have stated multiple times in this thread. Again, I am having an experienced industrial electrician do the install. Again, I am just trying to get an idea of the how's and why's of what needs to be done. I don't get how you can even pick up on details about the nature of my post but totally gloss over where I stated that I am not installing anything and that I am having a license industrial electrician do the install.
 
#22 ·
You say you have somone, but it sounds as if you don t trust the person. I am out of this.

- ibewjon
Not trying to be rude to you or CaptainKlutz but I would not lie about having an industrial electrician do the work. I have little experience with 3 phase power. I am a cabinet maker not an industrial electrician.

My entire reasoning for this thread is to get an idea on generally what needs to be done for setting this up. I am having no part in the install, but I would like to have some idea as to the hows and why's everything is being done. I think anyone on this board would agree that it is beneficial for the customer (me) to have some clue about what a hired contractor is doing on his machines and property.

I apologize if I came across hateful or if I wasn't clear on who was doing the work.
 
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