1919 A4 Forums banner
1 - 14 of 14 Posts

·
Premium Member
Joined
·
742 Posts
Discussion Starter · #1 ·
I currently run a SB Heavy 10 lathe and Bridgeport mill off a Phase-a-Matic R3? and never had any issues with my light use. However, I've picked up a couple of 5hp saws and would like to get a larger lathe at some point. I know the basics of converters like staying away from static units, 1.5 X max load, etc, but figure there's some good knowledge here to benefit from. I don't see running multiple machines at once nor having anything over 10hp. So my thinking has been a 15hp rated unit but that's about as far as I've gotten. I have 100amp service into my shop. I know they can be built but I'd rather just buy something theoretically built by someone that knows what they're doing. I'm happy with my small Phase-a-Matic but the bigger units are pricey compared to some of the other brands I see on ebay. And every time I dig deeper into one of the mfgs on ebay I get a lot of mixed reviews. I also really want a single unit that can run anything I have vs multiple VFDS like I think I'd need if I went that route (and I'm even less knowledgeable about those to begin with). Any thoughts, recommendations?
 

·
Premium Member
Joined
·
3,032 Posts
I can highly recommend the American Rotary ADX series. In three phase I run a Harrison 400 lathe with a 10hp motor, a Bridgeport Mill with a 2hp motor and a Reid surface grinder with a 1hp motor. The local power company wanted $13k to run three phase to my shop!! I'm a one-man shop like you, so sized my rotary at 20hp with an 80 amp single phase feed circuit. American Rotary has amazing customer service (they gave me recommendations for wire and breaker sizes for the entire 3 phase layout of my shop at no charge) and the unit has run without a hitch for just over three years. They aren't cheap, but neither is the equipment they run. Rebuild on a single phase 7.5 hp motor for my "free" air compressor cost $750.00, so I figure a converter is worth about what fixing a fried 10ph three phase motor would cost without all the hassle and down time.

https://www.americanrotary.com/products/view/adx-smart-converter

Here is a pic of my unit after it arrived but before it was hooked up.

Product Machine Electric generator
 

·
Premium Member
Joined
·
742 Posts
Discussion Starter · #3 · (Edited)
Thanks, that's one of the brands I'd looked at but had also seen some mixed reviews. Good to hear some personal experience. Called them and rep also recommended ADX20 given my potential needs. I was concerned that I didn't have enough juice to feed a 20hp unit but he explained it would only pull at the actual equipment load and a 10hp lathe should only be about 60 amps. Only ~ 2.5amps for the unit to idle w/o load. Does that sound legit? I'm a bigger is better guy but it's gotten me in trouble on more than one occasion.
 

·
Registered
Joined
·
966 Posts
Thanks, that's one of the brands I'd looked at but had also seen some mixed reviews. Good to hear some personal experience. Called them and rep also recommended ADX20 given my potential needs. I was concerned that I didn't have enough juice to feed a 20hp unit but he explained it would only pull at the actual equipment load and a 10hp lathe should only be about 60 amps. Only ~ 2.5amps for the unit to idle w/o load. Does that sound legit? I'm a bigger is better guy but it's gotten me in trouble on more than one occasion.
That's the gist of it. Here is the basic idea of all of this: Wire is sized on maximum amperage. Pull more amps than max, the wires turn into electric resistance heaters. Pull enough amps, and they set stuff on fire. Breakers are placed upstream of the wires to protect the wires from the load if the load pulls more amps than the wires can safely deliver. The breaker isn't there to protect the load. On a residential system, you can plug a 1 amp load into a 15 or 20 amp circuit but the breaker won't trip until that 1 amp appliance is long up in smoke.

In electrical, you'll hear the phrase 'pulling a load' or 'amp draw'. Electrical doesn't push a load. Your phase converter is on the 'push' end. So it's okay to have it oversized for the 'pull' of the 10 hp motor. It is slightly less efficient than a phase converter that is more evenly matched, but not enough to dicker over. When it's time to up-size, then you'll need bigger wires. And a bigger breaker to protect the wires. Wire size is a function of amp draw, length of run, style of wire & it's insulation, ambient air temperature and if it's run in a conduit, the number of conductors in the conduit so if you are running the wires a long distance or thru a hot attic, or multiple circuits in the conduit it's good to calculate the exact size to know where you are. A great shirt pocket reference for all of this is a booklet called Ugly's Electrical References. The web site is www.uglys.net

Motors are just a game of magnetic merry-go round chase. A motor will draw power as needed to keep up to the carrot of the chase, which is to say a 10 hp motor will only draw 1 hp of load if that's all the load is on it.

B-D
 

·
Premium Member
Joined
·
3,032 Posts
Thanks, that's one of the brands I'd looked at but had also seen some mixed reviews. Good to hear some personal experience. Called them and rep also recommended ADX20 given my potential needs. I was concerned that I didn't have enough juice to feed a 20hp unit but he explained it would only pull at the actual equipment load and a 10hp lathe should only be about 60 amps. Only ~ 2.5amps for the unit to idle w/o load. Does that sound legit? I'm a bigger is better guy but it's gotten me in trouble on more than one occasion.
That's pretty much the conversation I had with them, if memory serves. I believe we settled on an 80 amp circuit feeding the converter so that I could actually turn on all three pieces of equipment at the very same moment without harm. That scenario is a real stretch of the imagination, but I too am in the "bigger is better camp" when it comes to wire sizes in a particular circuit.
 

·
Premium Member
Joined
·
742 Posts
Discussion Starter · #6 ·
Thanks guys. I'm comfortable figuring out the breaker/wire sizes given run lengths, etc but didn't have a clear understanding of what the converter itself added to the mix. Was also hesitant on the American Rotary brand but feel better about them now. The price jump from 15 to 20 isn't that much but sucks you lose free shipping. Could probably detour through their place in WI later this year but in the meantime I'll keep out for a deal. Plus I swore many years ago I'd never drive through Chicago again!
 

·
Registered
Joined
·
1,469 Posts
FWIW, I started with a phase a matic 25 years ago with one drill press...

When i went to my third machine, I added an idler motor to the phase a matic - 5 hp. This REALLY improves the quality of the three phase circuit and draws almost zero power. I start the idler motor before turning anything else on.

Its still in use and i have a shop with ten three phase machines. never run more than three at a time though.
 

·
Registered
Joined
·
1,272 Posts
Three phase

The reality is..........you don't really need a phase convertor at all, just an idler motor. Get a fat-assed three phase motor and bolt it down, or put it on vibration dampners. Get a ten hp and be done with it. Position a three phase breaker within reach of the motor. Run your 220 single phase to the outside two legs. The motor goes on the switched side, so does your feed to your three phase devices. Make sure there is no load applied to your output side until the motor runs. Fixture a pull start lawnmower pulley to the motor shaft. Give her a spin, throw the breaker and abra-ca-dabra, you have three phase. I have seen small pony motors with a rubber friction wheel used to spin up the motor prior to starting, too.

You see, a three phase motor will run just fine in single phase once it's started. This is the case with your idler motor which then induces the third leg's power output. I'm told a 'Y connected ' motor works best. Not sure why( no pun) but mine is a delta motor and no problems.

Your manufactured third leg might be a few volts lower than the outside lines, but your average Bridgeport or engine lathe will never know it. A couple of electrolytic capacitors from that one out to the real legs will minimize that effect, but likely you won't find it necessary. My convertor takes in 240 volts single phase and delivers 240/228/240.

Just saying, you really don't have to spend a lot of money.

Next step up is to use a static phase convertor box to start your idler motor. This is how my lab runs now for 20years with zero malfunctions. I run VFDs , lathe, mill, drill press, automatic surface grinder, cold saw, band saw and plenty of sensitive equipment.........no issues.

Ryland
 

·
Registered
Joined
·
512 Posts
A friend of mine built my phase converter for me. It has a delta wound 10 hp motor with 3 capacitors. All I do it flip a disconnect switch to turn it on. Then turn on what machine I want to use. I think I have about $100 in parts in it.

Used 3 phase motors are fairly cheap to buy. I just sold a good 50 hp motor for $150 to a guy who is going to build his own phase convertor. Used 3 phase disconnect switches are cheap as well. Hard part is figuring out what capacitors you need and finding them.

Steve
 

·
Registered
Joined
·
31 Posts
I run the following 3 phase machines;

- 16x40 taiwanese lathe 10HP
- WWII vintage Oliver 232 table saw 3HP
- Northfield 12" Jointer 5HP
- Powermatic 180 Planar 7.5HP


I run them all off a 10HP multi plug unit from Grizzly Industrial / Smith Electric which can be found here;

http://www.grizzly.com/search?q=(categoryid:275030)

The 10 HP unit will start any combination of machines I have as long as one is running before the next one is started. Really it's a moot point since I can only operate one machine at a time as a single user.

If nothing else, you can look up the spec sheets and have a reference. Hope that helps!
 

·
Registered
Joined
·
966 Posts
Plenty of DIY on the 'net for making your own three phase rotary converter if you're up for that sort of thing. If you're worried about the quality of power or a weak leg, run it thru a VFD. VFD's convert incoming three phase power to dc power where it's switched on and off, then the DC power is rectified back to three phase AC power on the output. Wire a cheap potentiometer into the analog input on the VFD's contact strip and you got even voltage three phase power and a motor speed controller all in one. Put a drive conversion chart on the wall next to the speed control and use the motor rpm status on the VFD to dial up just the feed rate you want w/o having to change a belt.
 

·
Premium Member
Joined
·
742 Posts
Discussion Starter · #12 ·
One of the saws I want to get running is also old 5hp Oliver and forgot about the Rockwell 18" planer! Didn't know Grizzly had converters so may take a look at those. I'm DIY with just about anything but for some reason the phase converter thing just doesn't get my interest given the myriad other projects so looking for plug and play on that front. An old friend passed away recently and had a shop full of old machinery. I used to marvel at his 3-phase setup and always thought no one else could ever get it going but him given all the pieces of the puzzle necessary to fire it up. All too big for me but at least some of it went to museums and none to the scrap dealer.

Again thanks for the insight and I can't help but remember years ago when I was first trying to get my lathe and mill hooked up that then mod Mark G. deleted my post stating that it wasn't relevant to the site. And thanks for the PM offers but not what I want to do.
 

·
Registered
Joined
·
31 Posts
I'm DIY with just about anything but for some reason the phase converter thing just doesn't get my interest......

No worries. I face the same dilemma many times. I can build a lot of different kinds of stuff but at the end of the day I often have to make the decision whether I want to spend time building tools or actually get on with life and build the projects that started me down this artisan path.

Forgot to add, the grizzly phase converters are stackable. If you buy a 10hp today and in 5 years need to upgrade to say 15hp, you can just buy another 5hp converter and you'll be at 15hp total.

Good luck on whatever you decide!
 
1 - 14 of 14 Posts
Top