# By No Means Am I An Electrician !



## mmcmdl (Feb 2, 2016)

Long story short . Years ago I powered my shop with a 10 hp rotary phase converter . Bought it out of York Pa. from Wilke Mach . I believe for $1700 or so . I have moved and removed several times over these past years never getting the shop re-started . Couple months back I sold a pair of Ports to guy and he told me when I repowered , to go with a VFD . ?????

Could anyone explain this to me in Machinist terms ? I'm looking at probably 10 hp max .


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## T Bredehoft (Feb 2, 2016)

I admire your helper. I grew up with them, then in the last 30 years had two shelties. Their loss convinced me I couldn't stand another.


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## mmcmdl (Feb 2, 2016)

We lost this girl back in October . She was our 4rth child . I drove 1425 miles in 26 hrs. two days later and picked up a Sable .


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## CluelessNewB (Feb 2, 2016)

How many 3 phase machines do you have and what are the horsepower ratings of each motor?

Are you interested in adding variable speed to a machine?

VFD's have the advantage of adding variable speed but they typically are used with just one dedicated motor.  Generally they work out best for motors under about 3 hp.   (Yes you can use them for larger motors but they become less cost effective.)

RPC's won't allow speed control but work well with multiple motors and larger motors.

If you still have the RPC my guess that would be your best route.   If you want to add variable speed the plot thickens.


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## mmcmdl (Feb 2, 2016)

Thanks Rich . I no longer have the RPC . I will be connecting a 7hp lathe , a 2hp mill with variable speed and possibly my band saw if I can find the space. They are all 3 phase . I will not be  running the lathe and mill simultaneously if that makes any difference .


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## mksj (Feb 2, 2016)

The cost of a VFD that will power a 7Hp motor is going to be more costly (~$800-900) relative to a 10Hp RPC that you piece together new parts like a Phase-Craft + 10Hp motor ($600-700 with shipping). The VFD will take up less physical space, might be simpler to install (from a total wiring perspective to meet NEC code) and has some machine specific programmable parameters that have some benefits.  There are no de facto single phase VFDs rated for a 7Hp 3 phase motor, so you would need a 15Hp (11Kw) VFD that can run off of single phase in a derated mode (usually divide the the VFD rating by 1.7). Some VFDs will shut down with loss of phase, you need a model that can be run off of single phase in a derated mode. The VFD (depending on the model) on the mill could be run off of single phase or 3 phase from the RPC. Band saw would probably run off the RPC.


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## CluelessNewB (Feb 2, 2016)

What mkjs said!


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## David VanNorman (Feb 2, 2016)

I would go with the RPC  . to use the VFD you would need one for each machine  and like someone said the larger ones are not efficent.


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## mmcmdl (Feb 2, 2016)

I seem to remember some time back when the gear head Colchesters went to a variable speed drive . It had zero torque at low rpms . I'm guessing this would be the same case as a VFD driving a gearbox lathe ?
We had VFD's on most of our conveying systems down at my last plant , but torque was not an issue .


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## Keith Foor (Feb 15, 2016)

The issue with a 7 HP lathe is I would bet that it's got a coolant pump, light and other things that run from the main power feed.  None of that will work correctly if you are running it on a VFD.  It would all need powered from a separate power source, and since you stated that you don't have alot of electrical knowledge I would advise you to not mess with that.  You are familiar with using a RPC and that will do what you need to do.


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## Keith Foor (Feb 16, 2016)

Thought some more on this.  Mind you I know a good bit about electrical so when it came to building a rotary phase converter, I just got on the web and did some research and built one.  But that's me.  I will say that if you have a buddy that can be plied with beer and pizza that knows industrial electricity you may pull some info off the web and have him look at it and see if he thinks he could build one.  Another option is there are sellers out there that are selling control boxes that you connect to a 3 phase motor that give you a RPC but you don't have to pay shipping on a motor.  When you are getting into the 10 to 15 HP size motors, the shipping can be a bit much.   You would locally source the motor and then connect it to the control box.  For some guys that's a bit too much even and I understand that.  Electricity is one of those funny things that has a lurking potential to do serious harm and damage when it's played with or worked on by the uninformed.


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## Scruffy (Feb 20, 2016)

I bought a controll panel for a 15 hp from Jim at phase-craft. Had to give all the info off motor tag to him before he sold me the panel. He is the nicest person to deal with you'll ever find. Got all hooked up and a buddy checked the 3 legs with a meter and they almost matched perfect. Like 1 percent difference.
A year later I thought something had gone wrong with the panel, so I called Jim.         
He walked me through some checks and I found my 220 breaker had lost one side, not the panel.  Just saying his knowledge and help was well worth the small extra cost of scrounging parts and trying to build a panel myself.
Thanks Ron happy customer


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## mmcmdl (Jan 5, 2019)

OK , so here we go again . Have a SB heavy 10 wired 440 . Whats the best/easiest/cheapest way to get this running 220 single or is a static converter the way to go ? Can the existing motor be wired 220 ? Yank the motor and put a 110 in ?


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## Eddyde (Jan 5, 2019)

Since its 440V I'd assume the motor is three phase, since its a SB Heavy 10 I'd assume the motor is no more than 1hp.? If you only have 110/120V power available switching the motor may be the cheapest way to go but 115V single phase input 230V 3phase output VFD's are available up to 1hp. They are around $200.


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## kd4gij (Jan 5, 2019)

most 3 phase motors can be wired for 220 or 440 3phs. Just need to change some jumpers in side.


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## kd4gij (Jan 5, 2019)

Jumper for 220 and run it with w vfd.  It it is a single speed motor.


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## Keith Foor (Jan 6, 2019)

mmcmdl said:


> OK , so here we go again . Have a SB heavy 10 wired 440 . Whats the best/easiest/cheapest way to get this running 220 single or is a static converter the way to go ? Can the existing motor be wired 220 ? Yank the motor and put a 110 in ?



As far as the direct question about the motor in the lathe.  If the motor is a dual voltage motor it can be wired to 208-220  or 440.  Open the motor cover where the power goes in.  If there are 9 wires coming from inside the motor it's probably a dual voltage motor.  The data plate will also indicate if it's a dual voltage motor.    Now as far as 3 phase vs single phase.  If the motor is 3 phase, there is no way to directly run it off single phase power.  You would need a VFD or a rotary phase converter to create 3 phase power to use that motor.  If this machine is going to be the only machine you are going to be running then just get a 220 single phase motor and replace the 3 phase motor.  Unless you have a larger 3 phase motor sitting around to build a RPC out of you are going to spend more money building one than it would be to replace the motor with a single phase one and be done with it.  
Now if you are wanting to run multiple 3 phase machines in your shop then it's a better bet to build or buy an RPC that is big enough to run all of those machines.  

So the cheapest way
if this is the only machine,,,, replace the motor... if you have 220 in the shop buy a 220 motor,,,, if not, buy a 110 motor.
220 motor will be a similar price to the 110 motor but electric bill will be higher for the 110 motor.

If you have multiple machines, or plan on having multiple machines then depending on the number of machines an RPC is the next cheapest.

VFD's are always an option as well but at $200 or more per machine, they can get real expensive real quick if you have several machines to buy them for.


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