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Converting Monarch 10ee motor-generator 3-phase to single phase, Steelman method

Flail

Cast Iron
Joined
Oct 29, 2013
Location
Bonsall, CA
After recently acquiring a 1953 Monarch 10ee with a motor-generator I've been reading all the threads pro and con about preserving the M-G, using a phase convertor, using a DC drive or putting in a vfd and 3 phase AC motor. I then found the thread about http://www.practicalmachinist.com/vb/monarch-lathes/single-phase-power-motor-generator-10ees-153348/.
I thought this makes sense. It will cost about $40.00 in materials, allows the motor at anytime to be a nine wire or a 12 wire and doesn't degrade it's value to a purist, will save on the cost of a vfd or an RPC and the extra inefficiencies and complexities they would introduce to the system.
This thread details the practical steps to convert the 3 phase motor (of the motor-generator unit) to run on single phase. Basically it involves converting the Monarch 9 wire motor to a 12 wire motor. The problem is those 3 additional wires are buried deep within the motor buried under 60 year old grime and brittle varnish. Unfortunately the thread ends and doesn't progress to the point of opening up the M-G to do the conversion. Having more moxy than brains today I pressed forward and decided to look for the inner star point on the three phase motor. The M-G took maybe 30 minutes to wrestle out of the machine. All the wires have little metal tags to have identify them. In the first photo you can see the motor connector enclosure.

Motor Gen 1.jpg

The lower three connector are T1, T2, and T3 which contain pairs of wires to wire this in the 230 volt mode. T1 pairs 1&7, T2 pairs 2&8, T3 pairs 3&9. You can see the external star point as the bundle of wires held together with the nut and screw in bottom of photo. Wires 4,5,6 form this external star point.

Photo 2 shows the wiring plate for the 230 volt and 460 wiring connections.

[Motor Gen 2.jpg

You will need to pull the M-G apart to get at the AC field. First take the connector enclosure off. Then cut the tape that binds all the wires together on the outside of M-G. Pull off the fan cover. The fan is held on by 2 Allen screws that can be felt between the fan fins. Each bell end has #4 3/8" bolts and you'll need to take out the bearing retainer bolts as well. Disconnect the generator brush wires which go back into the housing before pulling off from bell. Release the brush holders and pull the brushes out of the holders. The armature will then slide out. The area of the AC field you need to access is in the center of the case and it will be impossible to access this area with the field in the case. Remove the 8 bolts that hold the generator fields in and remove the DC fields. Keep track of the shims. The AC field is held from rotating by one external bolt. The field is held in the case by friction. You will need to press the field out of the case. To avoid bending the field laminations you will need to press it out. I built this fixture to do this:

Motor gen 3.jpg

Motor gen 4.jpg

Put this into the case so the fixture cups the field and presses against the laminations. Align the legs of the fixture with the 4 ridges in the motor case that retain the field. Don't press or hammer on the field wires or you will have a paper weight. Support the edges of the case with 4 long bolts that screw into the cover holes and press the field out.
 
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Part 2

When you have the field out it will be filthy and it will initially seem impossible to sort out the wires.

Motor gen 5.jpg

The wiring harness is tied on with cotton string and impregnated with varnish. If you orient the field as shown with the bundle of wires down You will find the star point contained in a 5 inch fabric tube on opposite side of field nearest the laminations. A little brake cleaner helps!
See picture and dirty finger.
Motor gen 6.jpg

Use a small scissors to slit this open and the star point is inside.
Motor gen 7.jpg

Cut the star point apart and you can isolate the the ends of 10, 11 & 12 that correlate with 7, 8, & 9.
Add the new leads to 10, 11 & 12. I made a good mechanical connection then used silver solder.
What's nice about this modification is that it can be easily undone without taking the motor apart again as the internal star point is now another external star point. Therefore the motor can be made to function once again as a 3 phase and this modification is pretty undetectable to the next user.
Motor gen 8.jpg

Insulate high temp motor leads with fiberglass tubing and label wires, retie the wires with fiberglass string, then re-shellac this end of the field with armature varnish. The top three wires are the newly added wires.
motor gen 9.jpg
 
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Part 3

On another thread, toolnut posted about a Steelman convertor his brother had:

"I am not a fan of static phase converters but have recently learned about the H-A-S static phase converter system from Steelman Industries (previously named Steelman Electric). My brother purchased an old 16" wood jointer and when we picked up the jointer it included a 3 hp rated H-A-S static phase converter. This converter requires the motor be a 12 wire Wye connected motor for 230 volt operation and it claims to provide full nameplate horsepower by operating the motor as an unbalanced 2 phase motor. The efficiency is claimed to be above 90%. The earliest patent I found is # 2,922,942 and is dated 1960. I also checked the internet for Steelman Electric and found Steelman Industries which still sells the H-A-S converter system although it changed the design in 1999.
check out this website:
http://www.capacitorconvertors.com/p...structions.pdf

The kicker in this scheme is the motor must be a 12 lead motor or you need to modify a 9 lead motor to give the 12 leads so it can be reconnected.

What opinions do the motorheads and phase converter Gurus have on this design?
I searced the archieves and found no mention of the H-A-S system.

I inspected the interior of the converter and found it consists of a variable resistor, a n.c. potter bromfield relay, a start capacitor (200 mfd) and a run capacitor (40 mfd). Both of the capacitors were leaking and ruined but can be easily replaced. Both of the capacitor were connected between T2 and T3."


So if extrapolating if the run capacitor for his 3 horsepower convertor is 40 mfd and the start capacitor is 200 mfd then it seems a reasonable run capacitor for my 5 horsepower motor-generator would be a 67 mfd run capacitor and the start capacitor wound be 333 mfd.


I am waiting for some Glyptal insulating paint to arrive. I have the caps and relays here. This is a picture of the motor generator armature if anyone is interested. The left side is the DC generator and the right hand side is the AC motor. So in essence what happens is the AC motor is directly spinning the generator to manufacture DC power.

motor gen 10.jpg

The commutator is smooth and don't think it needs any work. I pulled the bearings off as they feel gritty. They are 25mm ID, 52mm OD, 15mm wide. Who would have thunk they'd be metric?

Lastly I got new brushes for everything from Helwig. For the generator there are four #13-373721, for the motor there are four # 13-371041. I was unable to find excitor brushes on their site.

I've spent some time reviewing Steelman's patent and there appears to be some misdirection there as opposed to his hookup instructions from the company website. In any case this will be a epic success or a colossal fail.

More to come when it's all back together............
 
"What opinions do the motorheads and phase converter Gurus have on this design?"

I designed the Steelman-like adaptation of a 10EE motor-generator system (230 and 440 volts) and posted it some years ago (cited in your post). My adaptation was specific to the 10EE and its slightly under-rated magnetic motor starter, by splitting the running windings across two of the starter's contact sets.

A Forum member implemented an H-A-S conversion, as described by Steelman, and measured the motor's horsepower using a prony brake measuring system.

The measured power was equal to or even slightly greater than the nameplate power.

So, the concept works, as we had expected.
 
"Who would have thunk they'd be metric?"

The Europeans invented the "frictionless" ball bearing. It is only natural that these be dimensioned in metric units.

There are indeed ball bearings which are dimensioned in Imperial units: the so-called "inch series". But these are oddities, and likely went out of favor with the demise of Hyatt and New Departure, and the partial or wholesale conversion of the U.S. automobile industry to metric, for the "world market".

Also, I believe, tapered roller bearings as used by all railroad locomotives and most railcars are dimensioned in Imperial units ("friction" bearings have been illegal in so-called "interchange" service for quite a few decades, and even a railroad's own "maintenance of way" equipment, which is seldom interchanged, have been converted to use rollers).
 
"What's nice about this modification is that it can be easily undone without taking the motor apart again as the internal star point is now another external star point. Therefore the motor can be made to function once again as a 3 phase and this modification is pretty undetectable to the next user."

You need not bring out all three, T10, T11 and T12, just two of these. But, DO remember which ones!

Should you later want to convert the M-G back to conventional mode, the two additional wires may be connected and then hidden within the motor end bell, or simply connected externally and a notation made of its purpose.

Your fixture is an excellent idea!

My local motor shop uses Sil-Phos brazing for all internal motor connections, from the (solid) copper "magnet" wire to the (stranded) copper leads.
 
Success!
I assembled the motor today, wired it up and it fired up slowly first time. I adjusted the potential relay as per instructions and it fired up in less than a second. Couldn't be more pleased thus far. In the first picture I am pointing at the location of the inner star point. You obviously can not gain access to this spot without pulling the field out of the motor. The field is red as it has been "shellacked" with Glyptol. Let it run for an hour and warms up but doesn't get hot.
5b7b3df72f0dd56f8c4fe356bc4189eb_zps5e406981.jpg


Here you can see the three components that make this possible. There is a 60uf run cap, a 300uf start cap and a Supco potential relay. About $20.00 worth of parts. I did an informal torque test by applying a 2x4 against the pulley while the motor was running. This did not appreciably slow the motor but it made some wood smoke.
403bf37235081d45a310f45de0c09522_zpsf281cc7c.jpg


Here you can see the caps and potential relay and motor. In addition to the 12 motor wires there are 6 generator wires.
4db99338c676c7d62fccb68248807f5b_zps4b5d19ea.jpg


I will post a wiring schematic in a bit.
 
Excellent work!

There is an extra ("spare" ?) 1/2" trade size threaded bore in the main contactor area.

This would be the perfect place to send and receive the additional conductors which are required of the Steelman method.

I would mount a steel pull-box (Hoffmann, or equal) under the headstock and connect this box (which would, of course, contain the P.R. and the caps) through to the main contactor area through a 1/2" flex or liquid-tight conduit.

With care, you could mount the box against the rear surface of the bed, using the raised portions as points to drill and tap for attachment fasteners.
 
"There is a 60uf run cap, a 300uf start cap and a Supco potential relay"

A 5 HP-rated potential relay can safely handle about 525 µF for starting capacitance, so that possibly a 3 HP-rated potential relay could be used in this specific case, although 3/5 of 525 µF indicates a maximum of 315 µF, so perhaps selecting a 5 HP potential relay at the outset is really a prudent choice. After all, this is an OLD machine (perhaps 70+ years old), and you only want to modify it ONCE.

Remember, in the original design (posted years earlier), I detailed where to insert the power factor correction caps. This could be done after fine tuning the conversion, and performing "clamp meter" amperage tests.
 
I just now received a SUPCO adjustable potential relay from the above-named source.

Yes, the intended application is starting and running of single-phase capacitor-start/capacitor-run motors on single-phase, but these are also useful for the instant case of three-phase motors operating on single-phase, using the Steelman method, as we know.

There is, indeed, an NC contact for the starting capacitor, but what would also be very nice to have is a delayed NO contact for the purpose of including that in the overload contact chain.

We'll see how far that idea gets, sometime soon.

My idea is this: as long as the load motor (in this case the 10EE's M-G) is really starting, and not overloading, the circuit to the main contactor would be complete. But, should the M-G fail to start, or should it overload, then the main contactor would simply drop-out, thereby protecting the M-G unit itself.

Good thing that the SUPCO adjustable P.R. is patented, and that the patent disclosure includes a complete schematic diagram, and all passive component values!
 
Irrespective of what the eBay sellers may state, the SUPR-branded "universal potential relays" are non-adjustable, whereas the APR5-branded "adjustable potential relays" are fully-adjustable.

List prices for the SUPR are about $19.95 whereas the APR5 are about $29.95, with actual price being somewhat lower.

The available documentation crosses the old STEVECOs to the equivalent SUPRs.
 
There is, indeed, an NC contact for the starting capacitor, but what would also be very nice to have is a delayed NO contact for the purpose of including that in the overload contact chain.

We'll see how far that idea gets, sometime soon.

My idea is this: as long as the load motor (in this case the 10EE's M-G) is really starting, and not overloading, the circuit to the main contactor would be complete. But, should the M-G fail to start, or should it overload, then the main contactor would simply drop-out, thereby protecting the M-G unit itself.

Good thing that the SUPCO adjustable P.R. is patented, and that the patent disclosure includes a complete schematic diagram, and all passive component values!

Peter,

Sounds like you're about to hack this thing. I'd like to hear what you come up with.

I was surprised, but pleased that Supco would include a parts list in the patent disclosure. It seems unusual.

The pics show 5 terminals, but I can't find a schematic that shows locations or functions of terminals 4 and 6. But, I have a feeling you'll tell us soon.;)

Neil
 
So here is the new junction box I put on the motor-generator. It is a 8"x12"x2". Got it from digikey. It holds the original terminal strip, the Supco adjustable relay, the run and start caps.

null_zps4780fdb8.jpg


null_zps0cc6d1f0.jpg


I left the M-G on the floor in front of the lathe instead of giving myself a hernia and ran some temporary jumper wires to the M-G. It fired right up the first time, but only in reverse! I will need to sort out this problem. Yes I know the pole barn is a pigsty. The extension cord is 230 volt not 115.

YouTube Video of it running
Monarch 10ee on single phase - YouTube
 
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Got the forward reverse thing sorted out. Headstock drum switch needed some adjustment. In this box the upper left relay has a constant arcing across the contacts (while running the spindle in either forward or reverse). What is its function and it looks adjustable. What is the correct way to adjust it so it doesn't arc across the contacts which I presume it shouldn't?

null_zps47b8c6e2.jpg
 
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"Sounds like you're about to hack this thing. I'd like to hear what you come up with."

I'm not planning on hacking it, just trying to understand it.

The Steveco adjustable is adjustable by virtue of two spring tension adjustments, which are sealed with tar after calibration.

The SUPCO is truly adjustable over a wide range. Electronically adjustable, not mechanically adjustable.

A downside of the SUPCO is the contact set appears to be very undersized for a 5 HP contact, compared with the Steveco which has the same HP rating.


"I was surprised, but pleased that Supco would include a parts list in the patent disclosure. It seems unusual."

Not without precedent, happily.


"The pics show 5 terminals, but I can't find a schematic that shows locations or functions of terminals 4 and 6. But, I have a feeling you'll tell us soon."

The two unused terminals are just there for the pass-through of the external motor controller's thermal overload leads to the motor's own thermal overload leads.

You get the SUPCO without "Fast-Ons" installed, plus you get a baggie which contains five "Fast-Ons" and five screws.

I suspect SUPCO's strategy was to provide a place for everything, and everything in its place.

Steveco elected to provide all "Fast-Ons" staked to the heavy duty Bakelite case cover by substantial rivets.

In contrast, the SUPCO case appears to be made from injection molded polystyrene. Not very substantial, in my view.
 
So here is the schematic I drew up of my components. Wish I had something simple to draw up schematics with a Mac. The relay basically parallels the start with the run capacitor for a second until the motor comes up to speed. When voltage get to about 310 it drops out the start cap. As a fail safe it will also drop out after a short period of time 1-1.5 seconds. As a test I put the lathe in forward (DC motor turned on) and the motor started anyway. This suggests this is not an iffy conversion if the motor-generator can start with a load on it.

e4e2e3a10c3020828b60067a1ee76696_zpsbd6a94a7.jpg
 
Also, got it running forwards and backwards at 3500 rpm. Runs same speed each way (via photo tachometer) and does full forward to full reverse in less than 5 seconds.
 
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"So here is the schematic I drew up of my components."

Excellent drawing.

What are you using as a motor controller, the fusible safety switch?

+ 3,500 rpm to - 3,500 rpm in 5 seconds is excellent.
 








 
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