Wanted: Rotary Phase Converter to run 1.5 hp motor

Anyone have one to sell?

Thanks,

QB

I ve got a home made on made on a 7.5hp motor. Never used it acquired it in a trade. Tim

I have one made by convert-a-phase, not much use on it, I needed 15 hp. Nice unit with a real baldor rpc "motor"
I think it is 10 hp though, will have to double check the size if you are interested.
$500, down near Paso Robles.

I know the OP asked about rotary phase converters but with such a small motor, and vfd's being so cheap, why not get a vfd and have all the advantages they have?

L7

Depending on needs, a static converter may do the trick. Low tech, low buck and easy to install.

lucky7 said:

I know the OP asked about rotary phase converters but with such a small motor, and vfd's being so cheap, why not get a vfd and have all the advantages they have?

L7

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Along with their disadvantages like a need to rewire machinery/loss of the machine's own controls and ability to serve only a single machine motor.

But in some particular situations VFD could be a wiser choice, of course. Unfortunately, the OP didn't describe his particular needs (machine type, plans to run more motors, etc.)

Rob F. said:

I have one made by convert-a-phase, not much use on it, I needed 15 hp. Nice unit with a real baldor rpc "motor"
I think it is 10 hp though, will have to double check the size if you are interested.
$500, down near Paso Robles.

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Little on the big side, thanks though.

QB

lucky7 said:

I know the OP asked about rotary phase converters but with such a small motor, and vfd's being so cheap, why not get a vfd and have all the advantages they have?

L7

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I have another machine fitted with VFD, but I want to keep the electrical and controls intact on this new machine.

Thanks

QB

Here is a pic for you question boy.

The reason that all of my machines are on VFDs is to KEEP the Original Controls ie same push button functions.

2¢

Question Boy said:

I have another machine fitted with VFD, but I want to keep the electrical and controls intact on this new machine.

Thanks

QB

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Shipping costs and delays, protective enclosures, switches, fuses or circuit breakers, "magnetic" starters or equivalent, etc, etc... add TIME for running wire, assembling it all, EG "cumulative f**k-with"?

These are not factors that scale "downward" very well. All you need is a 2 HP or 3 HP idler, but "mini" RPC are often a waste of time, if not also money.

Meanwhile.. 1-P input rated VFD in 2 HP and under could be the cheaper route. Sure don't cost much to ship.

Expect to operate this gadget how many hours a week?

Might be best to go in at 5 HP idlered RPC, and just "deal with" a larger ration of waste the few hours a year you actually have it powered-on?

A mere horse-and-a-half, one could operate off a 3-Phase inverter, solar-charged battery bank, utility-mains battery top-up, and have emergency power to keep fridges and freezers cold as a bonus?

So I don't have to run my Diesel but a few hours a day..

Toys. He who is BURIED with the greatest MASS wins?

WHHJR said:

The reason that all of my machines are on VFDs is to KEEP the Original Controls ie same push button functions.

2¢

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You lost me here. Could you please elaborate on how it is better to keep machine controls with VFDs vs. RPC or 3-phase service?

MichaelP said:

You lost me here. Could you please elaborate on how it is better to keep machine controls with VFDs vs. RPC or 3-phase service?

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OEM switches on Old Iron are still "as new"?

Not often...

There is external wiring to do whether one replaces OEM, re-purposes built-in controls, or replicates their functionality.

BUT... VFD or DC Drive, either one, all the externals are OEM-built noise-resistant AND low Voltage, low power. Read cheap to implement and inherently SAFE.

EX: OEM 10EE lathe, nearly all controls are 115 Volt DC, fairly stout switches, contactors, and their actuating coils.

VFD OR DC Drive there needn't be even ONE relay or contactor anywhere, and the heaviest switching load is a few milliamps @ 10 to 24 V - which is provided off the "black box" itself, so no need of a control transformer, either.

TOTAL time to wire can be about the same as wanted to implement an RPC. The wire and switches for VFD or DC Drive are cheaper and easier to find a place to mount.

Four 3-P motors on a Quartet combo mill, 5 HP down to 1/2 HP? RPC or Phase-Perfect made sense.

One already DC motor on a 10EE? DC Drive made more sense.

1.5 HP motor on the OP's dance-card is the only 3-P device? We know not, yet.

Swings and roundabouts...

MichaelP said:

You lost me here. Could you please elaborate on how it is better to keep machine controls with VFDs vs. RPC or 3-phase service?

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my guess is its because you walk up to the machine, turn it on and go....vs going and turning the rpc first and putting up with the drone. I've an RPC its good if you have a lot machines with larger motors, but cant' imagine wanting one for a small motor like 1.5, and the VFD should be a lot cheaper. Just wire the vfd controls into the machine's.

Then again all of this is OT....sorry OP, don't have one

Mcgyver said:

my guess is its because you walk up to the machine, turn it on and go....vs going and turning the rpc first and putting up with the drone. I've an RPC its good if you have a lot machines with larger motors, but cant' imagine wanting one for a small motor like 1.5, and the VFD should be a lot cheaper. Just wire the vfd controls into the machine's.

Then again all of this is OT....sorry OP, don't have one

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My question was addressed to WHHJR who has multiple 3-phase machines equipped by VFDs. He stated that he did so to "KEEP the Original Controls". I guess he meant to "PRESERVE the Original Controls" (by not using them), so I asked for clarification.

MichaelP said:

My question was addressed to WHHJR who has multiple 3-phase machines equipped by VFDs. He stated that he did so to "KEEP the Original Controls". I guess he meant to "PRESERVE the Original Controls" (by not using them), so I asked for clarification.

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Perhaps I should have said EACH machine has a control scheme that I choose to preserve. And as said the Drone, power waste, and separate star requirements are unacceptable to me.

Your opinions are yours, and mine are mine. In the beginning I had a static converter with idler motor It was a PITA for the above reasons well stated by Thermite. MY choice My money.

MichaelP said:

My question was addressed to WHHJR who has multiple 3-phase machines equipped by VFDs. He stated that he did so to "KEEP the Original Controls". I guess he meant to "PRESERVE the Original Controls" (by not using them), so I asked for clarification.

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lol, yeah not using is one way. For the pedantic, a more accurate description is "preserving the functionality" of the original controls....most important one being the on/off switch

Mcgyver said:

lol, yeah not using is one way. For the pedantic, a more accurate description is "preserving the functionality" of the original controls....most important one being the on/off switch

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Preserving - better-yet ENHANCING the ergonometrics of the "MMI" (man -machine Interface), can be the better rationale..

Example:

10EE originally had its "motor switch" implemented as a lever. Right at the nose of the HS. Just back of the spinning workholder.

Problem? If one was running a large chuck or faceplate, it could be a less-than -safe REACH-for. Later 10EE incorporated the functionality into the ELSR, placed the controls in easier and safer right-hand reach, tailstock end. Short lathe, so that worked. "Grew up" on 8 to 12 foot beds, so got used to having it all on the carriage. 10EE, that's easy to wire. Carriage only moves ten inches either way of centre. The Cazeneuve HB;s and the larger, later-model Schaublins? Shipped their lathes that way. Major controls are where your hands already ARE - same as a 1920's "large" lathe did mechanically.

There's a LOT of that sort of progress various OEM's made over the years to catch-up with in the "Old Iron" machine-tool world. OSHA wasn't ALWAYS wrong.

Either the OEM controls are already in just about as good a location as can be, where one benefits by preserving the location and function, even if newer (think oil-tight and/or illuminated) switches are an upgrade .. and/or eStop that had never been there is added.

Or they are NOT in the best location, and improvement can render an upgrade safer and more intuitive in regular use.

Use of VFD or DC Drive "as had" controls on their own panel?

Flexible, yes. Make use of new features, usually.

But improved placement for fast, safe, intuitive use when under stress? Not very often, even after getting used to them. Too often a one-step reach has become a multi-step action of fumbling multi-purpose "too tiny for fat fingers" buttons or having to go into the correct "mode" before punching-in commands.

So.. we tend to add the "remote" human-centric controls - just as the VFD & DC Drive makers wisely provide buffered and protected terminal points to enable adding.

Meaning we have wiring, panels, and switches to at least mess-with to replace worn or damaged in order to preserve, and not a great deal MORE work to it to also update.

TANSTAAFL

WHHJR said:

The reason that all of my machines are on VFDs is to KEEP the Original Controls ie same push button functions.
2¢

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Most often when fitting a VFD to a machine one eliminates all the original control wiring, with the motor power going *direct* to the VFD
and all control functions done through the low voltage logic signals associated with the VFD.

Mostly if folks want to keep the control functions bone stock then a rotary converter is the way to do.

WHHJR said:

...separate star requirements are unacceptable to me.

Your opinions are yours, and mine are mine. In the beginning I had a static converter with idler motor It was a PITA for the above reasons well stated by Thermite. MY choice My money.

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I'm not trying to tell you what to do. I genuinely wanted to know why you stated this because, as Jim explained above, the need to rewire or eliminate machines' own control is one of the main drawbacks of the use of VFDs. So to me, your statement sounded like "I always cross intersections on red light because I care about safety".

What's the "separate star requirement"? 3-ph wiring of the shop in addition to a single phase one?

P.S. And while we're on the subject, can you please share your approach to managing mechanical speed controls when a drill press, lathe or a mill used with a VFD? Do you still switch the levers, pulleys and Vari-speeds (and use VFD to regulate speed within a narrow range) or permanently leave them in one position?