3 phase for a tool with 2 motors

[projectnut]

Unless you want to get into rewiring the mill the easiest/cheapest solution is a static phase converter.

I’ve bought several from

Static Phase Converters

Static Phase Converters A static phase converter is used to generate 3 phase power during the starting of a motor. A static phase converter consists of one or more start capacitors and a start relay. The start capacitors produce electricity across the third winding of a motor during start up,

www.northamericaphaseconverters.com

And been happy with the service and performance.

Yes, he will loose some power but it’s unlikely he’ll notice the difference in a hobby shop. If he wants to go with a rotary converter later all it takes is a used 3 phase motor to convert the static box.

John

The North America phase converter company is based in New Berlin WI. They are now owned by American Rotary Phase Converter company out of West Bend WI. Over the years I have purchased 3 American Rotary static converters and one 15 hp rotary converter. About 7 years ago they purchased North America Phase Converter Company and dropped the American Rotary line of static converters. To that end I purchased a North America static converter to power my Black Diamond drill grinder.

All are still working fine, and I don't lack for power on any machine they are installed on. The original plan was to use the 15 hp rotary converter to replace all the static converters thinking they wouldn't last very long. The oldest one is now over 20 years old and still going strong. I'm not sure when if ever I'll install it.

 

[Ultradog MN]

I got a 20hp PP (I don’t think they offer anything between the 10hp and the 20hp). Strictly speaking I don’t have enough power in the service supply (100A residential service) to feed it to full capacity - but I don’t really need the full capacity - seems to work fine.

My RPC (that I don’t use anymore) is a 5hp Willet addaphase, it would start my 5hp air compressor (FLA of 15 amps), but it wouldn’t reliably start the 5hp setting on the lathe (trip the O/L protection in the RPC) - I’d spin it up on the low speed and switch to the higher speed. It was not a big deal because I generally run the lathe on the lower motor speed - the gear box gives a good range selection and the lower motor speed is quieter.

You bring up a good point.
I know some guys like the infinitely variable speed that a VFD gives them. On the other hand, my old lathe has 16 speeds - from 24 -1000 rpm . Yeah, I have to stop and switch gears but that is the kind of lathe I learned on and I haven't been Unable to do good work because I couldnt find the right combination of feeds and speeds.

 

[projectnut]

You bring up a good point.
I know some guys like the infinitely variable speed that a VFD gives them. On the other hand, my old lathe has 16 speeds - from 24 -1000 rpm . Yeah, I have to stop and switch gears but that is the kind of lathe I learned on and I haven't been Unable to do good work because I couldnt find the right combination of feeds and speeds.

If you have the right machine, you don't need a VFD. I purchased a Sheldon MW-56P lathe several years ago. It took a fair amount of searching to find one in good shape, but it was my first choice since the spindle speed is infinitely variable. I lucked out in that the lathe itself had just been rebuilt by the previous owner. He replaced all the bearings, several gears, and even had the ways reground. With all the extras he included with the machine I doubt he broke even. He included all the documentation for the parts and regrinding service.

The machine speeds are changed from 25 rpm to 2,200 rpm at the touch of a button. by a Worthington AllSpeed drive powered by a Merkle Korft gear motor. This is a rather unique lathe in that the spindle direction and speeds are all controlled by an operator push button station. It originally had a mechanical tachometer to display the spindle speed. That was missing when I purchased the machine so I replaced it with a Mach Tach.

 

[mksj]

At the cost of a new factory RPC (10Hp would be around 1-2K) these days, going with a digital 3 phase converter from Phase Perfect ($900-1300) may be a more cost effective option. The alternative is buy a Rotary Phase Control Panel ($300-400) and find an idler motor to connect it to. A static converter is also an option, I do not know how well they work with multiple motors (see posting below). The DPC's sold on Amazon do not work, they are just a static converter with some digital circuitry to switch the capacitors, so I would avoid those.

PTS003 - 3HP 230V Digital Phase Converter - Phase Perfect® Simple

www.phaseperfect.com

PTS005 - 5HP 230V Digital Phase Converter - Phase Perfect® Simple

www.phaseperfect.com

STK Panels - American Rotary

Phase Converter Panel - This DIY STK Rotary Phase Converter Panel is manufactured in Wisconsin by American Rotary and can be paired with your stock motor. (Motor not included, this is the converter panel only) *This is not a replacement panel. A detailed installation manual and quick...

www.americanrotary.com

Pro-Line Rotary Phase Converter PL-10

PL-10 BEST SIZED FOR: pl10 Best Performance Single Motor Start: 5HP Recommended 3 Phase Sizing: 15 Amps Total Combined Load: Please Call for Sizing (877) 545-2926 Easy Motor Loads up to 7.5HP... Table Saw, Drill Press, Milling Machine Medium Loads up to 6HP... Belt Sander, Grinder, Mixer...

www.northamericaphaseconverters.com

Will a Static Phase Converter Work For Two Motors?

I have just about finished up cleaning and repainting my VN no. 16 mill. Because it is just a home shop machine, and I won't be machining anything to aggressive, I decided to use a static phase converter. However, there is one 2HP motor for the main driving, but there is a small motor that...

www.practicalmachinist.com

 

[Dabbler]

Static converters and VFDs both have significant issues when attaching two motors, particularly if one is switched on and off. There are procedural ways to 'cheat' the system that works very well in limited circumstances. It gets really complicated, but the general idea is that the switchable motor cannot be more than 15-20% (better if it is 10%) of the main motor current. AND the main motor has to be running to use the smaller motor.

It is considerably more complicated than that. This is the oversimplified version. This is not to be attempted by anyone that does'nt have considerable VFD experience, or electrical enginneering knwoledge, or professional advise before attempting. It is pretty easy to burn out a motor or the VFD if you get it wrong.

 

[PNW_Guy]

Thanks for all the answers - especially those of you who focused on the question.

>> Unless you want to get into rewiring the mill the easiest/cheapest solution is a static phase converter.
I called them and was told it would require 2 separate static converters (one for each motor). This will require rewiring the mill, but that's not a big deal.

>> -Let me know the current ratings of each of the motors, and I'll look into it for you.
Thanks Dabbler - I'll take a look. I think the spindle is 1 1/2 to 2 hp and the power feed can't be much (1/2?).

>> An RPC obscenely expensive? I'm curious where you got that idea?
In my area used RPCs are more expensive than new ones.
Perhaps I should have said "hard to find and obscenely expensive on the used market where I live". He doesn't want to drop $2,000 on a mill and $2,000 on a RPC.

Thanks for the link the the RPC kit - that would make things much easier.

 

[Chipper5783]

Ultradog brings up a good point about not really needing variable speed on a lathe designed around a constant speed motor. I’m set up with a 3 phase system, but elected to convert a small Standard Modern lathe to VFD in order to provide that lathe a single phase supply (sort of as a handy little machine) - and the VFD was free out of my tickle trunk.

One operation that I do regularly, where it is nice to have speed change on the fly is for ”ramp out“ threading (full depth, then out, no relief groove) - it isn't any better, but I like the look. In order for that to work for me, I need a low spindle speed (~30), but want a higher speed for the run of the thread. My little English lathe allows shift on the fly while threading (it works great, a VFD would enable the same operation).

Generally speaking I don’t see variable speed as a game changer on a lathe designed to be a gear changer. Of course bling is always nice so I wouldn’t turn it down.

PNW in terms of the price - if you get the machine cheap, nothing wrong with paying good money for the extra stuff, at the end of the day the overall package price is still a good deal. My PhasePerfect cost me 25% more than the VMC that necessitated the purchase of the PP. However, a good sized, working, full feature 4 axis VMC with 40 tool holders for $14kCAD (machine cost plus the PP) is a good deal in my area. It sounds like your friend got a great deal on the mill. Obviously don’t pay more than you have to, but pay as much as you need to.

 

[MrWhoopee]

Unless you want to get into rewiring the mill the easiest/cheapest solution is a static phase converter.

I’ve bought several from

Static Phase Converters

Static Phase Converters A static phase converter is used to generate 3 phase power during the starting of a motor. A static phase converter consists of one or more start capacitors and a start relay. The start capacitors produce electricity across the third winding of a motor during start up,

www.northamericaphaseconverters.com

And been happy with the service and performance.

Yes, he will loose some power but it’s unlikely he’ll notice the difference in a hobby shop. If he wants to go with a rotary converter later all it takes is a used 3 phase motor to convert the static box.

John

I'm with John. I got my SPC from WNY and have been using it for 5 years now.

WNY Supply Online store for static phase converters

Just size it for the larger of the two motors and start that one first. The larger motor will then serve as an RPC for the smaller motor. My SPC is sized for my 2hp mill. When I want to use the lathe I start the mill (spindle disengaged) first. Your situation is even better suited with both motors on the same machine.

If you really want a full-blown RPC, I have a 7.5hp that isn't being used. It's not that far.

 

[PNW_Guy]

I'm with John. I got my SPC from WNY and have been using it for 5 years now.

WNY Supply Online store for static phase converters

Just size it for the larger of the two motors and start that one first. The larger motor will then serve as an RPC for the smaller motor. My SPC is sized for my 2hp mill. When I want to use the lathe I start the mill (spindle disengaged) first. Your situation is even better suited with both motors on the same machine.

If you really want a full-blown RPC, I have a 7.5hp that isn't being used. It's not that far.

I called North American Phase Converters, explained the situation and they said I'd need two static phase converters. He also cautioned me on using them on older than '64 motors. Not exactly sure what year the mill is, but it's definitely 60's vintage.

My initial post may not have been clear - the mill has one plug and two motors. Somewhere in the electrical box, the single power input is split, and feeds two different motors.

How much do you want for the RPC?.

 

[projectnut]

I called North American Phase Converters, explained the situation and they said I'd need two static phase converters. He also cautioned me on using them on older than '64 motors. Not exactly sure what year the mill is, but it's definitely 60's vintage.

My initial post may not have been clear - the mill has one plug and two motors. Somewhere in the electrical box, the single power input is split, and feeds two different motors.

How much do you want for the RPC?.

I'm not sure I buy into the not using SPC's on motors older than 1964. I have one on my 1960 Sheldon lathe and another on my late 1950's era Racine power hacksaw. I've had both machines for over 8 years. The lathe has run as much as 50 hours a week, and the saw has run as much as 20 hours a week. The saw is used far less than the lathe, but the lathe is normally being run 10 hours a week or more. The motors always seen to run cool, quiet, and have plenty of power.