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View Full Version : Where to mount a phase converter?



hornluv
06-03-2010, 08:04 PM
So, I bought a mill a couple of weeks back and the guy that sold it to me also had a brand new rotary phase converter that he had bought for the machine but never took it out of the box, so I bought that too. Where would be the best place to mount it? On the machine? On the wall near the machine? Bolted to the floor?

Also, what size wire should I be looking at for doing the wiring? I have a 20A 220V outlet that will be feeding it.

Thanks in advance,
Stuart

rockrat
06-03-2010, 08:09 PM
Mount it where you wont hear it run. Some have mounted them outside under a little dog house of sorts.

As for the wire, it will be based on the length of the run and the ambient temp that the wire will see. Find the NEC online and it will have the information there.

rock~

bob308
06-03-2010, 08:14 PM
if you are planing on getting more machines i would get a 3ph breaker box run the converter into that then wire from that like a 3 ph. service. that way it is easy to add another machine.

where to mount the converter well i started with it next to my desk right under the panel box. but soon did as stated above. moved it out side under its own little house.

SGW
06-03-2010, 08:15 PM
What rockrat said.

I'd just add that in general, for 20A you need #12 wire, unless there are extenuating circumstances. For less voltage drop you could go to #10.

Uncle O
06-03-2010, 08:22 PM
I put mine on the wall, up high. Made a sturdy shelf put some rubber feet on the motor and away it goes.

Carld
06-03-2010, 08:44 PM
How big the wire is depends on the amp draw of the mill motor and a little bit for the rotary converter.

So, what is the amp ratting of the mill motor.

Your not working in a library so why are you concerned about the sound of a motor running. My RPC is not so loud as to bother me and it's a 5 hp motor and you can't hear it when the mill or lathe is running. In fact, I put a lamp on the wall to let me know it's still on when I get ready to leave. I guess you could put the RPC and mill motor outside and run a belt through the wall to power the mill if you don't want the motor noise.

gnm109
06-03-2010, 09:02 PM
I have a 5 hp Phase Converter that I mounted on a stand. It sits next to the mill so that I can reach it to turn it on or off. I built the stand out of bed frames.

I have a 20 amp breaker on a 12 ga. line and the mill has a 3 hp induction motor. Both the RPC and the Mill motor run nicely as long as I wish without overheating.

When running with no load, it's a little noisy, sort of a high-pitched whine. Once I turn on the motor in the Mill, it falls completely silent. It doesn't bother me at all.

My lathe runs on 240 single-phase and I have no plans to add any more three-phase equipment. If I were to do so, I'd simply build a distribution box and feed the three-phase into that. I only operate one machine at a time.

Here's a picture. The phase converter is to the right of the machine on the floor with the switch where I can reach it.

The picture was taken just as I finished cleaning and painting the mill last summer. Since then, I've added a 2 axis Mitutoyo DRO and a digital Z scale as well as a 6" Kurt vise. It's working beautifully.

A phase converter is the way to go for me since the machine is a variable. I like the idea of a VFD with frequency-controlled speeds but if one of those were to quit, I'd be lost attempting to repair it. I can fix anything on the RPC.

http://i144.photobucket.com/albums/r188/gnm109/WebbChamp4VH002.jpg

mototed
06-03-2010, 09:17 PM
Mine was a home built unit it was so loud when I first plugged it in I could see why it would be mounted outdoors! It was bad out of balance, so I played around with some capacitors,got everything evened out, and now it's very quite. As quite as my machine motors running. Mounted it on a thin rubber pad next to the mill, just to keep the start up force from scooting it around.
Ted

andy_b
06-03-2010, 09:30 PM
Your not working in a library so why are you concerned about the sound of a motor running. My RPC is not so loud as to bother me and it's a 5 hp motor and you can't hear it when the mill or lathe is running. In fact, I put a lamp on the wall to let me know it's still on when I get ready to leave. I guess you could put the RPC and mill motor outside and run a belt through the wall to power the mill if you don't want the motor noise.

+1 LOL!!!!

Mine is a home-built 5HP on a handtruck with a 20' 10ga or 8ga extension cord (I can't recall offhand which it is). I wheel it to the general vicinity of the machine I wish to run, plug the extension cord into the closest 240V outlet, plug the machine into the panel box on my RPC, and let it rip. The cord wasn't that expensive, and it saved me from having to run 10ga wiring all over from a main panel for the 3ph. I plug into 50A outlets (so I can run my stick welder from the same outlets), but my RPC is fused for 30A.

andy b.

J Tiers
06-04-2010, 12:07 AM
There's loud, and there's loud......

I bought a 1 HP Arco a few years ago..... best investment ever.....

I got it pretty cheap, but when I ran it I could NOT figure out how the guy ever stood it mounted on a wall. I had it on the floor, on a board with rubber feet, wired up to a starter.

That thing sounded like throwing garbage cans and sheet metal down concrete stairs in an empty indoor pool area.

All the metal parts were loose, and the rotor had had the balance weights knocked off... It was one loud SOB. So I static balanced the rotor, tightened the sheet metal screws, and put a little strategic RTV on it.

Now it makes a slight hum with a few harmonics..... not bad at all, and I have it just outside the area wher the lathe is.

Boucher
06-04-2010, 12:14 AM
Mine was inside in my old shop and I hated hearing that thing run. So when I moved it got relocated outside.
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0012.jpg
The Shop A/C is on the right and the Rotary phase unit is shown on the left. I just poured a small concrete pad for it and covered it with an old window unit cabinet.
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0007.jpg
The other nuisance inside the shop was the air compressor. I moved it outside and 60ft away on the other side of the old barn.
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0008.jpg

Because I canít hear it, It is often left running. I am not sure how bad this is for the electricity bill. I have been intending to tie it into the lights so that when I turn the lights off it is also turned off. Also considered putting a red pilot light near the door I go out.

lakeside53
06-04-2010, 12:20 AM
I hate mine being inside... It's not a problem when the other machines are on as the noise is masked, but when I'm trying to concentate on other tasks - most annoying.

The 15 hp I'm building is going outside.

MichaelP
06-04-2010, 11:15 AM
Low rpm motors are usually way less loud than 3450 rpm ones. Yet I preferred keeping my low noise 15HP 1200rpm motor out of the shop.

Errol
06-04-2010, 11:56 AM
Put it outside on rubber mounts.

hitnmiss
06-04-2010, 12:47 PM
I had mine inside because I wanted the heat in winter. The noise drove me nuts, so I built an insulated (noise) box over it. Well that cooked a cap from excess heat (it was vented well but not enough)

Now it lives outside with a cover over it to keep rain off, been there for 3 years now and all's well.

hornluv
06-04-2010, 05:23 PM
How big the wire is depends on the amp draw of the mill motor and a little bit for the rotary converter.

So, what is the amp ratting of the mill motor.

The motor is 3.5 amps (it's a 1hp Bridgeport) and the converter I have is 6 kva.

Thanks for the responses everyone. I don't think I'll put it outside unless it's really loud, but you've all given me really great ideas.

Weston Bye
06-04-2010, 07:57 PM
This thread is timely as I'm currently installing an RPC for my Bridgeport. I will be mounting a box with a contactor and static converter on the wall next to the mill. For now, the motor will sit on the floor next to the mill, but if it proves too noisy I can move it outside under a cover like Boucher did. (good idea, using an old air conditioner cabinet) I purposely included a red pilot light on the control box to remind me that the RPC was on.

gnm109
06-04-2010, 09:07 PM
I used to be concerned about the whine that came from my RPC until I was working in my shop today. I had to turn on my big floor fan and that's five times as loud as the RPC.

I guess everythings goig to be OK. :)

Jim Shaper
06-04-2010, 09:16 PM
What kind of thermal issues would you have from a motor/rpc living outside in colder climates?

Weston Bye
06-04-2010, 09:22 PM
What kind of thermal issues would you have from a motor/rpc living outside in colder climates?

For the motor, nothing. The grease in the bearings might be a little stiff at first...

Jim Shaper
06-04-2010, 09:31 PM
That's kind of what I was getting at. We have 2 weeks a year that doesn't see above 0. Winter tends to last 5-6 months.

Then there's the issue of the motor being cool from overnight lows, and then the day warming up while the cool motor is sheltered in it's hut and then you get condensation.

Weston Bye
06-04-2010, 09:43 PM
Agricultural and industrial motors live their entire lives that way. Maybe life is shorter for them... A decently varnished winding on a three phase motor should not be bothered by condensation, or much of any other environmental factor. Avoid chinese...

gnm109
06-04-2010, 09:47 PM
Yeah, whatever you do, for Heaven's sake, don't get a Chinese motor. The one on my Enco lathe is 15 years old, the one on my Enco 7 X 12 saw is 25 years old and the one on the Webb mill is 23 years old. They are still running but you just never know, heck, they could quit at any time.

:)

The Artful Bodger
06-04-2010, 09:49 PM
Probably best to do away with the electrics all together. Overhead line shafting driven by a nice quiet steam engine is proven technology.

Weston Bye
06-04-2010, 09:55 PM
Yeah, whatever you do, for Heaven's sake, don't get a Chinese motor. The one on my Enco lathe is 15 years old, the one on my Enco 7 X 12 saw is 25 years old and the one on the Webb mill is 23 years old. They are still running but you just never know, heck, they could quit at any time.

:)

They don't build them the way they used to... 'Course, it will probably be an old motor that gets relegated to RPC duty. Mine (US made) appears to be over 30.

gnm109
06-04-2010, 10:04 PM
They don't build them the way they used to... 'Course, it will probably be an old motor that gets relegated to RPC duty. Mine (US made) appears to be over 30.


On the other hand, my 1940 Parks 4 X 12" Wood Plane has a 2 hp. Emerson Reverse Induction Motor that is the size of a large watermelon. It's still running after 70 years, too. I wonder when that's going to quit on me.


.

Jim Shaper
06-04-2010, 10:08 PM
The shorter lifespan is precisely what I don't want.

The motor in question is a US made baldor, and it's coupled to my 3ph generator head. The generator has a bit of surface rust from living such an existence.

Rattrap
06-04-2010, 11:53 PM
I put mine in the attic right over the office. Keeps slackers from hanging out there (the office, not the attic) and I never forget to turn it off when closing up shop.

wooleybooger
06-05-2010, 12:25 AM
my 5hp stays outside because my 14x40 rockwell lathe motor cabinet resonates like one of those big marching band drums and i didnt need extra noise from the rpc. i got all my stuff rigged up early winter last year and havent used it in one of our 100 degree + summers yet. my doghouse is scrap metal roofing and square tubing and airflow is beginning to concern me. seems mr. bourcher,s ac cabinet has solved that problem quite easily. my box,switches,and lights are all inside and i have planned for future expansions(i hope).

chipmaker4130
06-05-2010, 01:20 AM
How big the wire is depends on the amp draw of the mill motor and a little bit for the rotary converter.

Careful here. An RPC idler draws a 'little bit' while idling, no load. Startup surge is significant, but more importantly you don't get something for nothing. If the single phase for the machine tool and the RPC are sourced from the same supply, that supply must be adequate for the machine at full load PLUS the idler motor at an equivalent load. Realistically, if you have a 7 1/2hp RPC and a 7 1/2hp 3ph machine, both powered by the same single-phase source, you need a service capable of 15hp.

lakeside53
06-05-2010, 01:53 AM
On larger idlers, the way around the huge startup surge is to use a small pony motor. I was able to drop two sizes of motor starter (and significant reduction in wire size and panel breakers) on my 15 hp RPC. The pony and the idler are connected by 1:1 poly-vee pulleys, and a short belt. It's fully automatic - press start - it spins up on a 1/2 hp motor ( I could have used less) to full speed (1750 roughly), then 5 seconds later the power is removed from the pony and applied to the 15hp idler. Nice... and no big start caps, potential relays etc. I originally planned (and bought the parts) it to use start caps, but a pony made more sense.

My small 5hp idler with a 4 hp load ( not a good combination!) is not happy on a 240 volt 20 amp circuit - popped the breakers on lathe startup often. I had to increase the breakers to 30 amp and the wire to 10awg. My 15hp idler is on 6awg and 60 amp breakers, and will be fed to 30 amp fused disconnects.

dfw5914
06-05-2010, 02:41 AM
I mounted mine high on the wall behind my mill. I initially had it parallel to the wall and the wall acted like a big Toby speaker. Perpendicular to the wall is much quieter (duh). I made a wire rope isolator for one side and that got the noise level down to where I never bothered to make one for the other side. (other side sits on exhaust joint springs and a piece of foam)

http://i112.photobucket.com/albums/n188/pmhurco/June2010009b.jpg

http://i112.photobucket.com/albums/n188/pmhurco/June2010012b.jpg

hornluv
06-05-2010, 10:38 AM
Careful here. An RPC idler draws a 'little bit' while idling, no load. Startup surge is significant, but more importantly you don't get something for nothing. If the single phase for the machine tool and the RPC are sourced from the same supply, that supply must be adequate for the machine at full load PLUS the idler motor at an equivalent load. Realistically, if you have a 7 1/2hp RPC and a 7 1/2hp 3ph machine, both powered by the same single-phase source, you need a service capable of 15hp.

You guys have some pretty damn big converters! This is for a 1hp Bridgeport motor that draws 3.5 amps and a 6kva converter (not sure what that translates to in hp, but the guy I bought it and the mill from said he bought one that would handle 1.5 times the capacity). Would I be good to use 12 gauge wire or should I use 10? If I can convince the wife to let me spare the time, I'd like to see if I can get this thing up and running this week.

dfw5914, I really like your solution. I'd like to keep as much floor as possible and that looks like it will work perfectly.

Richard-TX
06-05-2010, 11:50 AM
I like the idea of a VFD with frequency-controlled speeds but if one of those were to quit, I'd be lost attempting to repair it.

That covers the vase majority of electronics today. Very few people have the ability to repair modern electronics. VFDs are so cheap that if you ever have a failure, just order a new one. For a 2 hp mill, a v/hz VFD is $145.00.

If you have a 5 hp or larger motor then a RPC makes more sense economically.

JoeFin
06-05-2010, 11:55 AM
That covers the vase majority of electronics today. Very few people have the ability to repair modern electronics. VFDs are so cheap that if you ever have a failure, just order a new one. For a 2 hp mill, a v/hz VFD is $145.00.

If you have a 5 hp or larger motor then a RPC makes more sense economically.

VFDs are a great solution for 1 piece of equipment.

But show me the guys here that can stop at only 1 piece of equipment

lakeside53
06-05-2010, 12:09 PM
You guys have some pretty damn big converters! This is for a 1hp Bridgeport motor that draws 3.5 amps and a 6kva converter (not sure what that translates to in hp, but the guy I bought it and the mill from said he bought one that would handle 1.5 times the capacity). Would I be good to use 12 gauge wire or should I use 10? If I can convince the wife to let me spare the time, I'd like to see if I can get this thing up and running this week.

dfw5914, I really like your solution. I'd like to keep as much floor as possible and that looks like it will work perfectly.


6KVA... is that the motor plate rating or some "can run" rating for the rpc? If it is the motor rating, it's likely a 6 -8hp motor (depends on the pf) - not all that small. A decent RPC will have fuses inside - check those - your breaker will need to be at least as big as those fuses. A picture of the RPC motor plate would help.


If it's a 3-5hp motor and running only your BP, it will run on a 20 amp circuit; for that you use 12 AWG. if you're unsure, then just put in 10awg and a 30 amp breaker. Your plugs need to be rated at least that of the breaker.

gnm109
06-05-2010, 12:44 PM
That covers the vase majority of electronics today. Very few people have the ability to repair modern electronics. VFDs are so cheap that if you ever have a failure, just order a new one. For a 2 hp mill, a v/hz VFD is $145.00.

If you have a 5 hp or larger motor then a RPC makes more sense economically.


I didn't know that the VFD's were that inexpensive since I never checked. At some point, I would like to try one since it would make drilling and tapping holes easier. I could just turn a potentiometer for speed changes instead of reaching up and tuning the crank after starting the mill.

I do like the simplicity of the RPC, however.

Weston Bye
06-05-2010, 12:53 PM
Just this morning I hooked up my RPC after 15 years of idleness and hooked it up to the Bridgeport. Everything runs well and the RPC, setting on the concrete floor on some stick-on felt furniture pads, runs quieter than the mill.

Eventually I will replace the bearings in the RPC as, more objectionable than a mild rumble, one of the bearings throws grease, making a shield necessary for the cleanliness of the shop. The bearings are not too bad, as it takes a full minute for the heavy old 1725 RPM armature to spin down to a stop.

gnm109
06-05-2010, 01:03 PM
Just this morning I hooked up my RPC after 15 years of idleness and hooked it up to the Bridgeport. Everything runs well and the RPC, setting on the concrete floor on some stick-on felt furniture pads, runs quieter than the mill.

Eventually I will replace the bearings in the RPC as, more objectionable than a mild rumble, one of the bearings throws grease, making a shield necessary for the cleanliness of the shop. The bearings are not too bad, as it takes a full minute for the heavy old 1725 RPM armature to spin down to a stop.


If I build a second RPC at some point, I'm going to use a 1725 rpm motor since they are generally quieter.

I wonder if there are any other pros and cons on a 1725 rpm motor versus a 3450 rpm motor for an RPC.

.

Weston Bye
06-05-2010, 01:31 PM
Phase-A-Matic

http://www.phase-a-matic.com/?gclid=CIfJgdmviaICFRMMDQoddxIVXA

recommends a 3450 RPM motor, although a 1725 RPM is acceptable for lightly loaded applications. They don't say why.

I suspect that the extra inertia at the higher RPM helps maintain phase generation. If that is the theory, then use the heaviest 1725 RPM motor you can find and maybe add a flywheel.

Paul Alciatore
06-05-2010, 01:54 PM
Mine was inside in my old shop .........

The other nuisance inside the shop was the air compressor. I moved it outside and 60ft away on the other side of the old barn.
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0008.jpg

Because I canít hear it, It is often left running. I am not sure how bad this is for the electricity bill. I have been intending to tie it into the lights so that when I turn the lights off it is also turned off. Also considered putting a red pilot light near the door I go out.

I wouldn't worry about leaving the compressor "running" when you are not in the shop. If there are no leaks, the tank will hold pressure and the motor will not run at all. If you have a leak, then fix it. Basically, you only pay for the air you use.

hornluv
06-06-2010, 06:33 PM
6KVA... is that the motor plate rating or some "can run" rating for the rpc? If it is the motor rating, it's likely a 6 -8hp motor (depends on the pf) - not all that small. A decent RPC will have fuses inside - check those - your breaker will need to be at least as big as those fuses. A picture of the RPC motor plate would help.


If it's a 3-5hp motor and running only your BP, it will run on a 20 amp circuit; for that you use 12 AWG. if you're unsure, then just put in 10awg and a 30 amp breaker. Your plugs need to be rated at least that of the breaker.

I just check the RPC nameplate and it says the maximum motor size is 3hp.

lakeside53
06-06-2010, 09:22 PM
Ah.. so it's is one of those fakey specs... ;) 3hp is about 2.2KW output power. It likely has a 3-5hp motor.

j king
06-07-2010, 07:47 AM
Here is my big pig lol. It is a 15 hp and I mounted it on wheels so I can move it to clean and if I need to work on it. Never have needed to.It is in a different room so its sound doesnt annoy me.http://img.photobucket.com/albums/v24/ikimjing/Mobile%20Uploads/downsized_0607000634-1.jpg

rockrat
06-07-2010, 10:30 AM
I run a 3450 rpm RPC and it works great for the shop. The higher rpm is supposed to even the phase angle out more than a 1750, or so they say.. One of the things that I added to it was a buffing wheel. It gives enough flywheel to keep the motor quiet and when I need to polish something up, thats where go. Buffing can take pressure, speed and heat to make something looks good and at 3450 @ 15 hp, I cant stall it when buffing. Makes things look nice.

The only thing that I have to install is a guard over the buffing wheel so that when I'm not buffing with it, it is not trying to grab the cat.

rock~

MichaelP
06-07-2010, 11:22 AM
The only thing that I have to install is a guard over the buffing wheel so that when I'm not buffing with it, it is not trying to grab the cat.
I got it! So the long cat that was pictured in a recent thread was yours?

lakeside53
06-07-2010, 01:17 PM
Here is my big pig lol. It is a 15 hp and I mounted it on wheels so I can move it to clean and if I need to work on it. Never have needed to.It is in a different room so its sound doesnt annoy me.http://img.photobucket.com/albums/v24/ikimjing/Mobile%20Uploads/downsized_0607000634-1.jpg


And with a 12 inch buffing wheel on that shaft, you can shine your shoes:D

j king
06-07-2010, 03:58 PM
Forgot to add that the 15 hp convertor starts on its own!Pretty cool

gda
06-07-2010, 06:24 PM
I mounted mine on the bridgeport - and run a couple of extension cords from it to the other machines. It is now part of a machine, rather than part of my home wiring.