1 to 3 phase problem

[stevet]

The electrical setup I have in my shop is as follows.
I have a static phase converter that starts a 3hp 220v 3 phase motor ( pony motor)
I’ve wired that motor to a junction panel and connected my surface grinder with separate vacuum motor as well as my band saw to that panel.
Both machines start and run fine.
I just wired my series one Bridgeport to the same panel and when I start the Bridgeport it draws a high load and the motor is louder than expected, sort of a groaning humming sound.
Once the motor is up to speed it quiets down. It’s a 1hp induction motor and I start it with no load, slacken the V belt
The motor is a Fairbanks, I believe it’s called a pancake motor, and it’s rated at 3.8A at 220v.
Any ideas what might be wrong.
Thanks, Steve

 

[Froneck]

You don't have a Pony motor, a Pony motor is a single phase motor used to start a 3 phase motor to be used as a RPC. The static converter you use to start the 3 phase motor is it still connected after the 3 phase motor started?

 

[thermite]

The electrical setup I have in my shop is as follows.
I have a static phase converter that starts a 3hp 220v 3 phase motor ( pony motor)
I’ve wired that motor to a junction panel and connected my surface grinder with separate vacuum motor as well as my band saw to that panel.
Both machines start and run fine.
I just wired my series one Bridgeport to the same panel and when I start the Bridgeport it draws a high load and the motor is louder than expected, sort of a groaning humming sound.
Once the motor is up to speed it quiets down. It’s a 1hp induction motor and I start it with no load, slacken the V belt
The motor is a Fairbanks, I believe it’s called a pancake motor, and it’s rated at 3.8A at 220v.
Any ideas what might be wrong.
Thanks, Steve

Fear not. Your hardware is in better shape than your description OF it...

To the extent your so-called "pony motor" does NOT have any "shaft load" placed on it, it is not a "pony" motor, it is a "pilot motor" AKA Rotary Phase Converter "idler".

So far, so good.

A(ny) static converter does ZERO "conversion" of itself. All it does is kick a 3-Phase motor off "rest" in a chosen direction of rotation, then run it on one winding set as single-phase @ a tad under 1/3 wotever the nameplate HP happens to be .. "etc"..

IF/AS/WHEN reconfigured properly, a "static" convertor-not-really can ALTERNATIVELY serve as a starter ON/OFF control for a "pilot" or "Idler" motor reasonably well. .and you THEN have a "Rotary Phase Converter".

Commercial makers of 'static' converters (NOT!) usually publish the 'how to' info, and we presume you have already put that into practice.

"So far" still good... you NOW HAVE a "Rotary" Phase Converter.

Already. And they DO "convert".

So you are about 75% of the way to where you need to get to.

Page Two:

You probably don't even need attention to run/balance capacitor values to better optimize the rig AS a proper "RPC", but can't hurt to review that.

Page Three:

Your REAL problem is that Phase Converters can struggle to START certain types of load motors and .. ta da... you NOW HAVE exactly that ... a challenging one.

An Idler larger than 3 HP is helpful, but not critical.

Try this first:

Simply turn on the saw and let it run, no load. Optionally the grinder instead. Optionally BOTH the saw AND the grinder. The "idle" motors added "stiffen" the 3-Phase power "pool", as if it/they were a larger idler AKA "flywheel".

NOW start the BirdPort. While the other(s) run, idle.

Should come up faster and easier.

THEN shut-off the idle saw / grinder / both.

Take two aspirin, let us know how it went in the morning.



If it is a Pain In The Anatomy? Upsize the 3 HP idler.

Or furnish a 'dedicated' supplementary idler to use instead of the other load-motors on the other machines.

As said, you are "almost there" already.

"Almost" isn't good enough.

Page four:

By now we have ruled-out your "converter" as primary cause of the problem. Or easily CAN rule it out.

There still COULD be faults in the BirdPort motor.

And probably ARE.

They are NOT ordinarily so hard to start as to NEED a 3 HP idler for a 1 HP load-motor.

What you have - if decently implemented - SHOULD power-up a TWO HP BirdPort.

The power system you have is not where I would look "first".

The BirdPort's motor doesn't sound healthy.

I'll leave sorting those birdporty bits to those expert in the ports of birds.

 

[JST]

A 3HP converter (idler) should run and start a 1 HP motor.

The pancake motors are a bit odd, and may draw more current than expected at start. Some regular motors are also "pigs" to start.

Yes, another 3 phase motor also running no load can act as an auxiliary idler.

 

[stevet]

Thanks thermite and JST.
I’ll try running the saw and surface grinder for additional starting help, take 2 aspirin and give it a whirl.
I’ll repost tonight after the test.

 

[Froneck]

I've never had a problem starting B'port pancake motors. Have a pancake motor on my Toolmaster that has variable speed with a 3HP RPC. Connected others for friends without problems. However I never had a static converter and RPC both running together to create 3 phase. If the Static converter and RPC motor are running together when you to start the BP I would try starting the RPC (motor you called pony) then shutting down the Static converter and let the RPC "single phase" then try starting the BP.

 

[thermite]

I've never had a problem starting B'port pancake motors. Have a pancake motor on my Toolmaster that has variable speed with a 3HP RPC. Connected others for friends without problems. However I never had a static converter and RPC both running together to create 3 phase. If the Static converter and RPC motor are running together when you to start the BP I would try starting the RPC (motor you called pony) then shutting down the Static converter and let the RPC "single phase" then try starting the BP.

He can't DOO that, Frank. His "static" has been made INTO an RPC.. by using it AS the (only) starter/controller.

He'd need to separate them and use a DIFFERENT starter/controller for the pilot/idler motor for it to do more than JF SIT there and "hum" itself.

(FWIW-not-much, I bought mine from member Jim Gorman - back when he was still making the very well-regarded "Phase Craft" RPC controller.)

They aren't HARD to DIY. Just tedious ... especially when one has other s**t to do that is NOT easy to "just buy".

Priorities thing, as it were.

 

[jim rozen]

Step one before listening to the 'gentlemen' above is to make sure the b'port is wired for low voltage, ie 240 volts.

 

[thermite]

Step one before listening to the 'gentlemen' above is to make sure the b'port is wired for low voltage, ie 240 volts.

Fair point, Owd Jim!

Nice thing about PM's "stone soup party" is that ANYBODY can contribute SOMETHING of value.



There is even a hit song about your dearly-beloved, if mostly wooden RPC:

"Love is a many Splintered Thing".

 

[Froneck]

Oh! I didn't know it was a single unit. I assumed by him saying he wired a 3 phase motor to the panel that the "Pony" as he called it was an RPC and Static converter used as a starter. I would assume it will have all the bells and whistles needed to automatically start a 3 phase motor and if it too were connected to a 3 phase panel easily disconnected by flipping a breaker allowing the 3 HP motor to single phase once started by the static converter.
Jim has a point, check to see if BP motor is wired for low voltage. Unloaded motor as he is loosening the belts will start and run on 1/2 voltage. Another thing to check is the connection. If as most BPs have a SO type cable for connection and 4 wire colors being Green, White, Black and Red it was very common that White was used as ground and Green as 3rd power. Prior to green wire White was coded to be neutral or ground. I have found many machines wired using White as ground connection and Green for Power.

 

[thermite]

Oh! I didn't know it was a single unit. I assumed by him saying he wired a 3 phase motor to the panel that the "Pony" as he called it was an RPC and Static converter used as a starter. I would assume it will have all the bells and whistles needed to automatically start a 3 phase motor and if it too were connected to a 3 phase panel easily disconnected by flipping a breaker allowing the 3 HP motor to single phase once started by the static converter.
Jim has a point, check to see if BP motor is wired for low voltage. Unloaded motor as he is loosening the belts will start and run on 1/2 voltage. Another thing to check is the connection. If as most BPs have a SO type cable for connection and 4 wire colors being Green, White, Black and Red it was very common that White was used as ground and Green as 3rd power. Prior to green wire White was coded to be neutral or ground. I have found many machines wired using White as ground connection and Green for Power.

"If necessity is the Mother of Invention, then Assumption is the Mother of all f**k-ups."

The late, great, Field First Sergeant "Willie" Williams. 101st Airborne. The jump into Holland. And not-only.

He never claimed it was original. Just that understanding it had kept him alive - given I served under him in 1965.... and saw him retire a 30-year man ... with all his arms & legs still working good enough to HUMBLE we 18 to 20-somethng alleged "athletes".



I rather suspect it is a Law of Nature?

 

[Froneck]

As said to assume is to make an ass of self! But the OP stated he added the 3 phase motor to the 3 phase panel. I'm thinking he had the static converter connected to the panel to operate the other machinery and later added the motor when he wanted to add the BP. I assumed what he did, my bad! But the OP was not very clear as to how the system is wired and why I originally asked if both were connected at the same time. There is no mention of the Static converters size.

 

[JST]

A "static converter" is generally fine for starting an idler. All the relays etc normally in the fancy box are really just doing the same thing..... starting a 3 phase motor to run on single phase.

In fact, one of the companies that make both SPCs and RPCs has an app note on their site for doing just that. It can be a simple way to get going, workable, even if perhaps not the best.

The diagram is at the end of this link: https://phaseconverters.phase-a-matic.com/Asset/SIS-UL 2021.pdf

 

[thermite]

As said to assume is to make an ass of self! But the OP stated he added the 3 phase motor to the 3 phase panel. I'm thinking he had the static converter connected to the panel to operate the other machinery and later added the motor when he wanted to add the BP. I assumed what he did, my bad! But the OP was not very clear as to how the system is wired and why I originally asked if both were connected at the same time. There is no mention of the Static converters size.

My initial POINT was he seemed to have DONE all the right stuff. His saw and grinder were "hard evidence".

He simply didn't explain it as well as he wired it.

Had a cousin outta the great metropolis of "French Creek" West Virginia .. back in the day before it became such a large city.. NOT.

Roscoe Phillips had made hisself a name for being able to fix magnetos for tractors and ag equipment. He'd get all pontifical explaining how they wuz surrounded by "dead electricity" until the rotation stirred it up and converted it to "live electricity".

Nobody gave a damn what he SAID.

The magnetos he fixed always worked and the farmers work got DONE.

Not bad for a seven year old kid?

So me went-on to make a good living at it as a heavy-equipment, Diesel, truck, and coal-mine machinery maintenance guy.

Even read a book or three as he got to where he could get his hands ON a "book".

You'd have had to know barefoot-poor "French Creek" in the 1940's and '50's?

Or maybe just next week?

 

[Froneck]

I have been waiting to see the results of the OP's test. Turning on more 3 phase motors and let them idle will add to the 3HP RPC. I do it all the time! On the other hand Jim's suggestion to check voltage wiring was great and I feel it might be the problem. But there is a possible other problem that will become greater if more motors are turned on to increase RPC HP. Static converters are designed for a given HP and are automatic in that changes are made electrically as the motor they are supplying comes up to speed. Start Cap is removed, a run cap maybe be used as well as possibly balance caps. But if HP is increased the static converter might not function correctly. I don't know the size nor internal function of the Static converter, maybe the 3HP motor was added to run the BP motor. The fact that it starts the low HP motors on the surface grinder and band saw does indicate connection correctness but not function correctness. The Static converter might as connected work with lower HP but not as HP requirement is increased. That will show up when he tries adding other machinery motors HP to increase RPC motor size. I would think using a static converter as a way to start an RPC is OK but if the system is connected to a number of different motors the static converter should be disconnected once the RPC motor is running and more so if the size of the static converter is equal to or slightly less than the 3HP RPC.

 

[stevet]

Sorry for the follow up delay. The holidays are to busy a time for me to spend in my shop.
Checked the wiring on the BP motor and it is wired correctly for low voltage.
I tried running the saw and surface grinder with the idler then starting the BP and that didn’t seem to make a difference.
Then I ordered a couple of run capacitors and wired them in.
Not much difference with the BP starting but the voltage is closer to balanced and the idler motor runs much cooler.
Maybe this is just the way the BP motor at home is going to sound at start up and I’m use to my other BP at work snapping to instant, full speed.
The one at work is on true 3 phase power.

 

[DaveKamp]

It sounds like... to me... that there's something not-quite-right.

My gut says that somewhere, there's a wire that isn't nail'd down quite tight enough, or it has a fair amount of resistance in it... or the pancake might have spent too much time in the pan.

Mebbie disconnect the pancake's wires and give it a visit from an ohmmeter, mebbie it'll show something awry?