Which grade of American Rotary converter do I need?

I’ve finally got tired of bolting VFD’s on everything and want a rotary.

Primarily furniture type shop- right now I have a big edge sander, a narrow belt sander , hinge borer, and a carbide grinder which need to run.
A upgrade to the dust collector probably and a CNC router might eventually come into shop.

So right now in my one man shop just the 5 hp edge sander with its 1/2 hp oscillating motor running as one time load(I am leaving drives in gear that currently has them).
I can imagine upgrading to dust to 5hp.
So near future two simultaneous 5hp motors.

I called AR and the tech said to go 20 hp ADX.

What say you guys- I am trying to control cash flow just now so 2k out the door on the ADX is a bit much.
Just cobble something together - used 10 hp motor and AR box..
It seems AR get such good reviews that I want to stick with their gear.
I’d like the thing to be as quiet as can be expected.

What has been your experiences- start small and just upgrade as you go or just drop in a larger unit than currently needed.
I guess as I stand I need the ten, 15 is a bit of buffer.
But the AR vs AD or ADX series- do I need the more expensive types?

I have to admit- it would be nice(probably worth it) to just ring AR up and have them ship a unit.
I am sort of worn out with looking around for used gear.

Woodshop equipment tends to have a lot of inertia, big rotating things on some stuff, including dust collectors and planers. Things that are harder starting.

VFDs start machines slowly, and do not have to supply a huge starting current. The RPC will be starting stuff the same as the power line would, full starting current surge right away.

Probably best to go with the usual rule for hard starting equipment, and have the RPC idler double the HP of the stuff you will run at one time. That suggestion of the 20 HP is not bad.

You cannot count on the dust collector to help with starting, the way folks often suggest an idling 3 phase machine does. The dust collector has a load on it whether it is sucking dust or not, it's not "idling", so it has little extra capacity to help.

You might get by with less, but it depends how much you want to screw with it.... the 20 HP ought to be a once and done solution, that has some capacity for expansion, as well as better starting of harder loads.

Ok thanks.
This is probably a case of if I bothered to ask the manufacturer which product to use I should probably take their advice.

I worked with AR several years ago on my application and when the dust settled their recommendation was right on no matter how I recalculated it. When I picked it up at the factory I was taken in the back and the tech folks showed me how to hook it up as I was using a remote switch. I went with the ADX, not sure why other than hard starting. If you want one I would recommend bite the bullet once.

Bob

I have an AR and always found it to be real noisy, was like that new. I also was using 2 shop made rotary converters that worked like a champ and never a problem in 30 + years until one day I hit the on switch and one didn't start? Thought it was time to upgrade and bought a lightly used PhaseAMatic to replace it with and liked it so much I found a good price on another to replace the other.
I find no problems with the same size as the biggest motor I run and starting several other machines too so I don't know where the rule comes from to always go with a bigger converter? The fellow that built both of mine said to go ahead and load em up and as I said it never has been a problem. I do have wiring on both sides that is oversize enough to allow for plenty of safety and expansion later if needed but that was only for piece of mind, maybe that is why it wasn't a problem. I have the three phase hard wired with several receptacles on both side walls and the rear end wall with a plug on each machine and wanted to never have to add bigger wire.
Anyway; I'd recommend the PhaseAMatic brand and even though I can't guarantee it I do think a 10HP unit would work fine.
Dan

I have built two RPC's from scratch and advised on a couple.

As far as noise is concerned, its just a motor idling.

The control box does two things. It starts the idler (start circuit) and balances the phases. Unless you are skilled at industrial control, I would not advise building your own box.

There is the circuit wiring and contactor that need to be big enough for the currents and the capacitors. The heavy cost is the motor. AR can tell you what range of motor sizes a box will handle. Look into buying a box for a 15 or twenty horse motor but use a 7 1/2, 10 or whatever is adequate for your current needs. Add to or replace the motor when needed. If you are adventuresome, buy just the box and add your own motor. If the motor is totally enclosed, put it outside to keep it sound down.

Or just bite the bullet and be done with it.

Tom

I have seen many of American Rotary's youtube infomercial videos.
They are all marketing fluff, with no real technical explanation
on the subject of selecting and sizing. Just a lot of feel good,
marketing crap. For that reason alone, I would never buy from them.
They give away a lot of free converters to youtube makers, and that
does not win any points with me either.
There are some key things that make a quiet and reliable RPC.
Not sure they know these things, as many people have mentioned
how loud their converters are.
Do your research and build you own.
This might not work for some people, as so many have an entitlement
mentality, and would rather pay their money and have someone on the
phone to complain about when it does not work they way they think
it should work. Some people can not handle being responsible for
making things work themselves. What ever group you are in,
do whatever you need to do to satisfy the voice(s) in your head.
Good luck.

-Doozer

What- you saying I’m crazy.

Lol but these damn voices...

Ok- so a nice young lad wants to buy a control box.
Whatcha all think.
Buy AR or that eBay guy Croman?

Tom- that’s a real good tip on buying larger box.
For some reason I was assuming these were lock stepped for each size.

This 20hp is available- should I sweat type or is this close enough?:

Trboatworks said:

What- you saying I’m crazy.

Lol but these damn voices...

Ok- so a nice young lad wants to buy a control box.
Whatcha all think.
Buy AR or that eBay guy Croman?

Tom- that’s a real good tip on buying larger box.
For some reason I was assuming these were lock stepped for each size.

This 20hp is available- should I sweat type or is this close enough?:

View attachment 253670

Click to expand...

What's the reference to Croman? I don't see anything in the label specs to cause a problem. I take it you can get the motor cheaply?

Tom

I have a 20 hp AR converter. Flawless for about 10 years. I know 2 other shops that bought AR converters on my advice, flawless as well. The only noise is the motor idling away. I bought the idler from AR as well. Baldor with no exposed shaft, sits on rubber, makes a quiet hum, no big deal. Another thing to think about is AR has technical support 24/7. I just can't say enough good about them, so nice to get What you pay for.

TDegenhart said:

What's the reference to Croman? I don't see anything in the label specs to cause a problem. I take it you can get the motor cheaply?

Tom

Click to expand...

Croman Converters (seller jdc) is one of the eBay sellers who puts together boxes.
He is at $375 for a 20 hp.
AR is at $450 for theirs.

That Toshiba 20 hp motor is asking $350.. seems ok price wise.
Been listed for awhile- maybe get the thing for $250 or $300
Right now I’d rather be at the $700-$800 into this thing than off the shelf at 2k

car2 said:

.... Mine has a Baldor idler motor, and seems most any decent idler of a given size will produce about the same sound level, ...

Click to expand...

You are quite incorrect with your assumption.
All motors are not created equal. There are specific
things that make a quiet or not so quiet motor when
used in an RPC application.

-Doozer

I picked up a box from Croman Converters. 15 hp for $275.00 Ordered a 10 hp, but the free 10 hp motor turned out to be a 15 hp.. Just upgraded the $250.00 box to a $275.00 15 hp one instead Was in the box, just about ready to be shipped..I did end up driving out to his place in Gaston, Or. and picked it up.. The only negative about the box is he uses sheet metal screws to hold on certain things in the box.. They stuck through the back of it. Trimmed with a die grinder, and was good to go. Other then that one issue, my RPC works excellent . The motor is a Taiwan built Tatung 1755 rpm 208-230/460 volt TEFC Super quiet, and very smooth. Starts my 5 hp Cincinnati mill that also starts up a 2 hp knee motor at the same time. Total price was a bit over $300.00, and mounted it on a plasma cart I was always tripping over.. He (Croman) has been building them for about ten years,and use to sell the parts only kit.. Everyone wanted a turn key box now, so he went that way..

Not my first post here, but the software does not let me log on my original name..

BrandXXX what is other name or don't you want us to know it?

Tom

Trboatworks said:

Croman Converters (seller jdc) is one of the eBay sellers who puts together boxes.
He is at $375 for a 20 hp.
AR is at $450 for theirs.

That Toshiba 20 hp motor is asking $350.. seems ok price wise.
Been listed for awhile- maybe get the thing for $250 or $300
Right now I’d rather be at the $700-$800 into this thing than off the shelf at 2k

Click to expand...

tr, FWiW I have a 5hp homebuilt RPC and a 10HP American Rotary panel with a scrounged idler motor. I've used both trouble-free for years, the latter for a 3HP chop saw, 10EE lathe (about 5HP equivalent), 2HP surface grinder, and 2HP bandsaw (loads a lot like yours). Often more than one at once. The American Rotary model designations have apparently changed but I know the one I bought was the economy version.

I use VFDs too (bridgeport, T&C grinder, drill press) but prefer the RPCs where the frequency control is irrelevant.

Depending on how the panels and ideler motors price out it might make sense for you to do what I did and have more than one RPC (I added the 10HP after the 5HP one was maxed out on smaller machines).

car2 said:

So are you going to grace us with your knowledge of what the specific things are, or just tell us we are ignorant, assuming one is not using a crap motor.

Click to expand...

Dunno what he suggests, but using a 3450 rpm motor is generally noisier than a 1725 rpm motor. An enclosed motor will usually be quieter than an open or vented motor.

TDegenhart said:

BrandXXX what is other name or don't you want us to know it?

Tom

Click to expand...

Just Scott V. Mostly plasma/welding posts.. BTW was going with the American Rotary box with my motor, but I decided to go somewhat local.. The Mill was run on a homemade parts kit from Croman built by the last owner. He was happy too.. Main thing about going that way, Croman would send me parts to tune the rotary if needed..His is just a mom, and pop operation, and stuff seems to work well. He also is open on where he finds motors, and other things when you pick his brain..

The motor I got is from a guy I sold a plasma cutter too. He wanted me to go with a real nice VFD,because that is some of the work he does.. Has 25 employees running out of his shop with many large Three phase welding machine.. Complete shop is solar powered, and quite impressive. Told him I wanted old school for power to start, and he got that.. I had a VFD on my little mill before, and they work well, but the Rotary has proved to be the right pick for me. Christen told me this motor was a good one, and boy was he correct there.. Super quiet, and everything runs like shore power.. Going with a 3 phase Plasma on it, and I am right at the peak as far as output.. If it passes this test, then I will have 100 percent of what I needed in three Phase power.


Edit,
Ran my Thermal Arc LM-200 Inverter on my Rotary today. Just wired it for 3 phase. Was outputting 300 amps, and 28 volts with some .045 dual-shield wire.. Looks like I am going to be good to go with the 3 phase inverter Plasma cutter.. The box is preforming flawlessly . Should of done this 20 years ago.. Always thinking you need a phase Perfect for this stuff, but sometimes just winging it is good too.. Old school has it's good points.

Hooked up a brand new Thermal 60i plasma cutter to my rotary today.. The 3 phase only plasma works perfect off of the 15 hp Rotary. If fact it works just like my single phase model of the same thing.. You don't get anymore electronic stuff then these new digital plasma cutters. Cut one inch steel to test arc length and amp draw.. Was pulling 30 amps on the wild leg sometimes with zero faults. The Croman box, and the Taiwan motor turns out to be the best $300.00 I have spent in my shop..

Amazon was blowing out the Thermal Dynamics cutters again, and picked up a cutter without torch for $397.00 after rebate.. Already scored a deal on a few single phase units. Got my Mill in a trade for one.. The 3 phase unit is staying in my shop,so I could care less about single phase power on that one..

I have another question on this one guys.

When choosing a idler- what NEMA rotor type is optimal?

I was reading this thread in which B, C and D are noted:

Picking Rotary Phase Converter Size - How big do you really?

In particular post #24


But what about Nema type A?
I am looking at two similar motors- a A and a B.
Significant difference for this application?
I understand that this will work with most anything but I can also buy most any type so would prefer to buy the one best suited for task.
I am looking at fairly new ‘ high efficiency’ types.

Thanks guys

Tr,

Im just going to throw this out... chits and giggles.
Myself, I had invested a bit in quality VFDs before making the jump to an ADX40 for my CNC machines.

I decided to keep my investments, with the thought of reducing inrush current that might negatively effect my CNC equipment.
I am running 2 Fadal 4020s straight off the ADX, a 5hp Quincy compressor, bridgeport, and 618 surface grinder on VFDs congruently.
I have lots more gear, but I have to be picky of how and when I run it.
Restricted by the ADX40, but feel if I were without the VFDs, I'd be even more limited.

Just my opinion.