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914Wilhelm
11-01-2013, 12:58 AM
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/ . This thread details the theoretical 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.

http://i972.photobucket.com/albums/ae201/914wilhelm/a39d73a89aa8d68e69637409da3aea90_zps777ceaa1.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.

http://i972.photobucket.com/albums/ae201/914wilhelm/51778abe109478e109f4c661f123e360_zps070b8cd4.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 1/2" 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. 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 with the field in the case. Remove the 8 bolts that hold the generator fields in and remove the 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 get a piece of pipe that is bigger than the field but smaller than the case. Revision: later is a fixture I made to push out fieldThis only needs to be a few inches tall. Cap one end which you will press against. Put this into the case so the pipe cups the field and presses the laminations. Don't press or hammer on the field wires or you will have a paper weight. Support the edges of the case and press the field out. When you have the field out it will be filthy and it will initially seem impossible to sort out the wires.

http://i972.photobucket.com/albums/ae201/914wilhelm/15c9687106029fa2213e7a866b7697cb_zpsd3732d91.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.

http://i972.photobucket.com/albums/ae201/914wilhelm/bbf0cdc613c7cb1f32ce745d189db4b0_zps71aaa082.jpg

914Wilhelm
11-01-2013, 12:59 AM
Use a small scissors to slit this open and the star point is inside.

http://i972.photobucket.com/albums/ae201/914wilhelm/13ab1ee648c03bff04019a500d8b5141_zps85daef75.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.
http://i972.photobucket.com/albums/ae201/914wilhelm/null_zps0967dd4f.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.
http://i972.photobucket.com/albums/ae201/914wilhelm/null_zpsd8292b0d.jpg


Then reassembly is opposite of disassembly as they say. When I get this reassembled I can start experimenting with capacitors. Name plate states it pulls 14 amps at full load. Any guesses at capacitor values? My initial thoughts each field pulls 4 2/3 amps in its parallel configuration. The 3-6, 9-12 field is now in series and this field will pull 1 1/6 amps and I'm thinking that's what I should use to calculate the capacitor values. 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 fail.

914Wilhelm
11-01-2013, 12:59 AM
Here is a link to the Steelman patent: http://www.google.com/patents/US2922942

And a link to it's PDF: https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US2922942.pdf

And a link to the device installation instructions: http://www.capacitorconvertors.com/pdf/staticinstructions.pdf

Oh, and by the way, the motor can now easily be converted back to 3 phase as the old inner star point leads (10, 11 & 12) will now be outside the motor and can be starred back together without re-disassembling anything.

914Wilhelm
11-01-2013, 01:00 AM
Here is a fixture I welded up to help push the field out then back in without damaging the wiring.

http://i972.photobucket.com/albums/ae201/914wilhelm/60a69485ed16a019a70878dc89d73692_zpsca3c2867.jpg

http://i972.photobucket.com/albums/ae201/914wilhelm/00f830865a8ac5681b7effc3c4ce5c43_zps0e1752ec.jpg

PStechPaul
11-01-2013, 02:13 AM
It was interesting to see a thread about converting a three phase motor to single phase, as I did just the opposite. But I completely rewound the motor with much heavier magnet wire so that it runs at about 8 VAC. My reasoning was to run it at 180-360 Hz and in so doing it is theoretically possible to get several times the power from the same size motor. This is often done for EVs.

As mentioned in the other thread, it is possible to run a three phase motor on single phase by adding a capacitor to the third leg. I tried it, but at reduced power, and it probably results in much lower torque and poor power factor, which might not be the case with the patented method being tried.

I was unfamiliar with the Monarch lathe and I found some interesting information here:
http://www.lathes.co.uk/monarch/ and http://www.lathes.co.uk/monarch/page2.html

It seems that the motor-generator is used to provide DC power to the drive motor which was controlled by early electronic speed controls that were standard before modern VFDs were available. So perhaps all that is necessary is a good source of DC, although ideally perhaps the drive motor could be replaced with an AC version and a VFD could be used. It seems cumbersome to convert a three phase motor to single phase if its only purpose is to drive a DC controller and motor.

The main issue with a simple rectifier circuit to provide DC is the power factor, which is especially bad if large capacitors are used for filtering. But perhaps the DC motor and controller can run OK on an unfiltered supply. Otherwise, there are some PF corrected switching supplies that might provide the voltage and current needed. A standard 120V 20A supply is only good for about 2100 watts or 3 HP, but a 230V 30A circuit can supply 6000 watts or about 8 HP.

Good luck on your project. I just wanted to provide some additional information and possibly another way to accomplish what is needed.

BTW, it might be possible to estimate the capacitor value by using:

X(c) = V/I = 230/14 = 16.4 ohms

C = 1 / (2 * pi * f * X) = 1 / 6193 = 161 uF

This seems like a reasonable value based on the other thread's estimate of 40 uF / HP.

Here is an article about simple home-made phase converters:
http://www.homemetalshopclub.org/projects/phconv/phconv.html

gt2ride
11-01-2013, 09:33 AM
Here is a unit I made for my lathe. Three hp motor and a vfd. Works great

http://i175.photobucket.com/albums/w147/gt2ride/HPIM1152.jpg (http://s175.photobucket.com/user/gt2ride/media/HPIM1152.jpg.html)

macona
11-01-2013, 04:55 PM
My solution:

http://www.practicalmachinist.com/vb/monarch-lathes/retrofit-10ee-drive-ac-brushless-servo-motor-154967/

macona
11-01-2013, 04:56 PM
I was unfamiliar with the Monarch lathe and I found some interesting information here:
http://www.lathes.co.uk/monarch/ and http://www.lathes.co.uk/monarch/page2.html

It seems that the motor-generator is used to provide DC power to the drive motor which was controlled by early electronic speed controls that were standard before modern VFDs were available. So perhaps all that is necessary is a good source of DC, although ideally perhaps the drive motor could be replaced with an AC version and a VFD could be used. It seems cumbersome to convert a three phase motor to single phase if its only purpose is to drive a DC controller and motor.

It is significantly more complicated than that. Look up Ward-Leonard Drive:

http://en.wikipedia.org/wiki/Ward_Leonard_control

PStechPaul
11-01-2013, 07:19 PM
OK, that explains a lot. It seems that there are actually three elements involved, with a "prime mover", in this case a three phase AC motor, coupled with a DC generator, the output of which is controlled by varying its field current. The output comes from the armature, which then drives another DC motor which drives the lathe. Thus variable speed at constant torque can be obtained by using a relatively low power adjustable resistor (rheostat) to adjust the field of the generator. Reversal is obtained by reversing the armature connections, and higher speed at lower torque can be produced by reducing the field current of the lathe motor.

Here is perhaps a clearer explanation of the operation of the lathe motor itself, which is shunt wound:
http://www.brighthubengineering.com/diy-electronics-devices/123625-understanding-shunt-wound-dc-motors/
http://electrical-engineering-portal.com/classes-speed-control-starting-dc-motors

I think the same performance may be obtained by use of a solid state shunt DC motor control. Instead of the motor-generator used for adjusting armature current, phase-fired SCRs can do the same thing directly off the AC line, although they do create lots of harmonics unless inductive and capacitive filtering are used. The field voltage does not require very much current and can be controlled with a small adjustable DC supply, but usually this can be just a simple fixed rectified DC voltage.

Some solid state drives that should work:
http://www.solidstatedrives.com/default.aspx?act=Catalog.aspx&catalogid=47&Subcategory=All+Motor+Controllers&category=KB+Electronics+Penta+Power&browse=&MenuGroup=solid-state+drives+web&desc=KB+Electronics+-+KBCC-125R&&AspxAutoDetectCookieSupport=1
http://www.ebay.com/itm/New-KB-Electronics-DC-Motor-Control-KBIC-240D/300695565383 ($74 for 1-2 HP)

Here is a representative schematic for a complete speed control for a shunt wound motor:
http://www.industrial-electronics.com/image/block-diagram-dc-drive.jpg

And here is a much simplified schematic:
http://www.daenotes.com/images/SCR-DC-motor-control.JPG

J Tiers
11-01-2013, 07:37 PM
it would seem that a substantially easier way to go about it would be to use a "static phase converter", which will allow enough power for most non-industrial applications.

That has the advantage of being available, to begin with. And it involves no major surgery, nor any somewhat irreversible changes to the motor.

I do not refer to the "Steelman" or similar schemes, which are in general for motors with substantially constant load, with the classic example being an irrigation pump. The lathe inherently has a varying load on it, and a standard "static converter", which usually is no more than running the motor on single phase with 3rd wire open, will work as well over the wide range of loads.

For industrial use, 3 phase will be available, so it would be a non-issue.

Wayne Sippola
11-01-2013, 07:42 PM
Awesome write up, I do hope you add it to the PM Monarch site - they would love to see it. I got a 10EE a couple years back but the MG was missing. Made the decision pretty easy to go to a VFD and 3 phase motor. Although I read about the conversion theory on PM, I don't recall anyone actually trying it. Kudos to you!

As far as using a DC drive, can be done, but not cheap or easy, nor likely to be anywhere near as robust as the original. Or so I've read - I'm no expert on this.

Wayne

Doozer
11-01-2013, 09:24 PM
I have a Hendey tool and gaugemaker lathe and all the original
motor/generator stuff works. I tried it on a static converter
(which is nothing more than a capacitor to start the motor)
and it starts and runs, but has no power. If I really turn up the
spindle speed fast, the generator slows down the 3phase motor
and it kinda growls to a slow down. I tried this rig with a rotary
converter powering it, and it works fine. I can wing the rheostat
speed up fast as I please and the spindle motor responds crisply.
My Hendey has the same setup as the Monarch, except it has a
rectumfrier tube instead of the belt driven field current genny.
I figured it was silly to have a rotary driving a 3ph motor, driving
a genny, driving the spindle. Even if the whole mess works, I found
a 10hp vfd and a 7hp 3ph motor for my lathe.

--Doozer

914Wilhelm
11-01-2013, 10:37 PM
The thing to remember is a static convertor sits external to the motor and basically allows the motor to attain 66% of power if tuned correctly. The Steelman convertor basically rewires the field and the claim is it allows a 3-phase motor to attain 90+% of its power. We shall see how it works. I am awaiting fiberglass insulation tubes, motor varnish & fabric covered motor wire which should come this next week. I also ordered brushes for the motor generator, the DC motor and the exciter from Helwig Carbon Products as all were worn to nubbins.

Doozer
11-01-2013, 10:44 PM
I am following your conversion, as I might try it instead of converting to VFD.
Are you buying anything from Steelman or rolling your own totally?
--Doozer

914Wilhelm
11-02-2013, 01:43 AM
I'm going to roll my own. My understanding is the box contains a run capacitor, a start capacitor that is 5-10x the run cap, a relay and a potentiometer. On the PM site I saw where someone had a Steelman box so I'll ask them to look inside at capacitor sizes. If I get this to work I'll post pics and a working drawing.

The PM site person posted this information:

"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 3 horsepower is 40 mfd then it seems reasonable the run capacitor for 5 horsepower would be 67 mfd and the start capacitor wound be 333 mfd.

J Tiers
11-02-2013, 08:55 AM
The thing to remember is a static convertor sits external to the motor and basically allows the motor to attain 66% of power if tuned correctly.

Actually, they run the motor same as an RPC idler..... on 2 of the 4 wires, as a single phase motor. The 66% is correct, long term, based on heating. That can be improved a bit with a run capacitor set for highest power factor at max load.

Upside of static converter: very easy, no disassembly, no complicated "doubletalk" explanations when you go to sell the machine, zero problems when and if you yourself get 3 phase.

Downside of static converter: "only" 66% of max power for serious hogging, torque ripple is much larger unless a run capacitor is used.

Downside of conversion; Still single phase, higher torque ripple than 3 phase, added tendency to chatter due to torque ripple, very invasive surgery needed to do it, hard to undo compared to adding a converter externally, lots of explanations when and if you sell the machine, especially to someone with 3 phase available.

BEST solution: Put in a VFD that is simply set to 60 (50) Hz. Set accel to get it going correctly, and never look back.

lakeside53
11-02-2013, 11:53 AM
The most overlooked part of a static converter is it doesn't limit the power to 66% (or 50% or whatever); YOU have to do that or risk burning up the target motor. A correctly tuned motor overload section on a starter, or thermal sensing on the motor can help considerably, but many simply ignore the problem.


I'm with Jerry - I'd have just used a vfd on to drive the monarch motor (which then drives the generator).

dian
11-02-2013, 12:28 PM
i have this:

http://i973.photobucket.com/albums/ae218/romandian/Berufsmatur013_zpsf19264b8.jpg (http://s973.photobucket.com/user/romandian/media/Berufsmatur013_zpsf19264b8.jpg.html)

to drive this:

http://i973.photobucket.com/albums/ae218/romandian/Berufsmatur014_zps5377f9af.jpg (http://s973.photobucket.com/user/romandian/media/Berufsmatur014_zps5377f9af.jpg.html)

30 amps (300 max) at 200 v dc. cost me 100 bucks for both.

wouldnt that power the monarch? (the box, i mean.)

914Wilhelm
11-09-2013, 11:33 PM
I've updated earlier text and pictures.
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.

http://i972.photobucket.com/albums/ae201/914wilhelm/4fa94d2f9018856ceec530f87a3a38c2_zps2cba4e0f.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.

MichaelP
11-09-2013, 11:52 PM
Guys,

Please help me understand the reason behind going through the conversions. What's wrong with the original Motor-Generator arrangement of 10EE?

You're not going through all this just to eliminate need for 3-phase supply, are you?

macona
11-10-2013, 12:19 AM
OK, that explains a lot. It seems that there are actually three elements involved, with a "prime mover", in this case a three phase AC motor, coupled with a DC generator, the output of which is controlled by varying its field current. The output comes from the armature, which then drives another DC motor which drives the lathe. Thus variable speed at constant torque can be obtained by using a relatively low power adjustable resistor (rheostat) to adjust the field of the generator. Reversal is obtained by reversing the armature connections, and higher speed at lower torque can be produced by reducing the field current of the lathe motor.



Nope, the drive motor requires field weakening to achieve anything past base speed, 800RPM. Second issuer is the motor is a 240v DC motor, not 180. Most drives that do that require true three phase to run.

macona
11-10-2013, 12:21 AM
Actually, they run the motor same as an RPC idler..... on 2 of the 4 wires, as a single phase motor. The 66% is correct, long term, based on heating. That can be improved a bit with a run capacitor set for highest power factor at max load.

Upside of static converter: very easy, no disassembly, no complicated "doubletalk" explanations when you go to sell the machine, zero problems when and if you yourself get 3 phase.

Downside of static converter: "only" 66% of max power for serious hogging, torque ripple is much larger unless a run capacitor is used.

Downside of conversion; Still single phase, higher torque ripple than 3 phase, added tendency to chatter due to torque ripple, very invasive surgery needed to do it, hard to undo compared to adding a converter externally, lots of explanations when and if you sell the machine, especially to someone with 3 phase available.

BEST solution: Put in a VFD that is simply set to 60 (50) Hz. Set accel to get it going correctly, and never look back.

There are those that have tried static converters on 10EE and they perform terribly. On startup they overload the MG at it's reduced power availability.

macona
11-10-2013, 12:31 AM
Guys,

Please help me understand the reason behind going through the conversions. What's wrong with the original Motor-Generator arrangement of 10EE?

You're not going through all this just to eliminate need for 3-phase supply, are you?

There are only a few ways to drive a M-G 10EE. First is by true three phase, of course.

You could also use a VFD, there would be a bunch of wiring to do and you would need a VFD somewhere in the 10HP range. I am not sure anyone had done this.

Second is by a rotary phase converter. I used a 15HP one on my 10EE. I think you can get away with as small as a 10HP, the motor in the M-G is somewhere around 6.5HP. On my machine with the idler running and the M-G running I was pulling about 5kw out of the wall without the spindle even running. And it is rather noisy:


http://www.youtube.com/watch?v=ioS6_Qk1SoA

Why replace? Because you are eliminating a potential show stopper if the drive dies. There are a lot of parts in the control box that are just not available any more and there are no replacements available. Parts have to be scrounged from other EE's most of the time. In general all of the M-G 10EE's are over 65 years old now, nothing, especially electrical, lasts forever. And my retrofit performs even better than the original stock drive.

macona
11-10-2013, 12:34 AM
After the retrofit:


http://www.youtube.com/watch?v=si4MWsdGQpE

MichaelP
11-10-2013, 12:41 AM
There are a lot of parts in the control box that are just not available any more and there are no replacements available. Parts have to be scrounged from other EE's most of the time. What exactly is there that has no replacements available, vacuum tubes or anything else? I'm not familiar with the control of 10EE. Did anybody try to replace the control with one made of modern components and leave the rest as is?

macona
11-10-2013, 01:09 AM
You have three moving components of a Motor-generator 10EE. The Motor-Generator itself, the exciter, and the spindle motor. Any of these can be rewound by a motor shop but that gets expensive real quick. You really can't get much done from a motor rewind shop for less than $500. The spindle motors can bird nest, armatures wear, exciters do the same as well as the generators can fail.

The electronics is a bunch of special relays that just are not made any more, and there were several versions of the control box made so you can have different variants in the same year. Some have contactors with replaceable contacts, some dont, some have one kind of acceleration relay, others have another. The speed control is two special high power rheostats that I believe can be custom made, but at a high price.

The first tube drive, the Wiad and the successor, the module drive, use some rather expensive tubes. The two main thyratrons are rather delicate and are at least $300 a piece when they die. Tube drives were used up to about 1983 when they switched to a solid state drive, these can only be ran from true three phase power, no rotary converters here.

The problem with removing the old drive is that the spindle requires 240v on the armature and 115v on the field. The base speed is 800 rpm, you need field weakening to get to the 2400rpm limit of the motor. You also need field loss detection so that if you do loose the field the motor just won't run away.

There are very few solid state drives that can supply 240v, almost all are 180v. The few that do require either a step up transformer or true three phase to run them. There is a company that makes a 10ee solid state retrofit but you need the boost transformer from a Wiad or module drive to make it work. And it is something like $3000.

So, after all that it is just simpler to replace it with newer tech. VFD and a new three phase motor is the cheapest. Servo is the most expensive but the best performing. You could put a 180v DC motor with tach or encoder feedback and get very good performance as well.

The Artful Bodger
11-10-2013, 01:14 AM
......deleted by me............(failed to read full topic!).............

lakeside53
11-10-2013, 01:18 AM
Sure. 5-10hp genuine single phase input from a few manfs, and up to 30hp. Not cheap, but them nothing of size is.

PStechPaul
11-10-2013, 01:37 AM
I found a web page (previously posted as well) that describes the various configurations of this lathe and the control boxes:
http://www.lathes.co.uk/monarch/page2.html

It seems that the recommended "fix" is to remove the entire MG set and also replace the DC spindle drive motor with a three phase motor and VFD, or a high power DC servo, either of which can provide the precise variable RPM and quick acceleration, braking, and reverse as demonstrated. Thus, the OP's intention of rewiring the three phase motor of the MG set for single phase may not be the best thing to do, especially if there are problems with the control box, or deterioration of the DC generator or DC spindle drive motor itself.

Other possible alternatives are synchronous motors and stepper motors, but they may be difficult to find (and expensive) in the power range desired.

The reason for the higher cost of larger VFDs made for single phase input is the need for a solid DC bus voltage. The usual bridge rectifier and filter capacitors cause very poor power factor and thus much higher current draw and possible distortion of the line voltage. Power factor correction involves adding a switchmode power supply front end and high frequency power conversion that smooths out the current draw so PF is close to unity, and the VA draw from the mains will be close to the actual power.

One way to achieve the same thing is to use a battery bank to supply the DC link voltage, which is about 300 VDC for a 240 VAC three phase VFD. If you have a photovoltaic solar panel installation this voltage may already be available, but otherwise you can get 25 12V batteries and an appropriate charger. 12 Ah SLAs are about $25 each so for $625 you will have 3.6 kWh available which can provide short term power of at least 7.2 kW (about 10 HP), and it can be charged at about 2 amps for full charge overnight. Plus you have a backup power source in case of grid power outages.

MichaelP
11-10-2013, 02:08 AM
Thanks guys. My desire to get a 10EE has shrunk significantly.

macona
11-10-2013, 03:23 AM
Don't let the minor issues with the drive stop you from getting one of the best tool room lathes ever made. All lathes with infinite variable speed have issues. Hardinges have a reeves drive that wears, rivetts have their issues too.

The wiad and module drives work great and they are native single phase. The only thing that is 3 phase is the coolant pump. The design is a work of art.

MichaelP
11-10-2013, 03:47 AM
Thank you for the encouragement Macona. :)

Peter.
11-10-2013, 05:29 AM
What exactly is there that has no replacements available, vacuum tubes or anything else? I'm not familiar with the control of 10EE. Did anybody try to replace the control with one made of modern components and leave the rest as is?

Yeah, me. My AC motor was cooked, and I don't have 3-phase power so with help from here and PM I hooked up a new electronic drive to power the field and armature using the lathe's original control panel and speed control pot. The downside is that the power is reduced by approx 30% until I fit a step-up transformer as I can't get 240vDC from the drive from my 240vAC supply. Up-side is that my machine is very quiet and looks original.

MichaelP
11-10-2013, 10:57 AM
Thanks Peter.

dian
11-10-2013, 11:39 AM
"Plus you have a backup power source in case of grid power outages."

interesting. so what in my home will run on dc power? lamps maybe? (will they?) anything else? what happens, if i feed dc power to the computer?

PStechPaul
11-10-2013, 04:13 PM
Anything that has a switching supply should be able to run on DC, since the first thing they do is rectify the incoming AC. This may also be true for CFLs and LED lamps, and of course incandescent lamps don't care. But you can just use the three phase output from the VFD. It can be set up for 50 or 60 Hz and 120 or 240 VAC. You might need to balance the load somewhat, but the usual loads like lamps, computers, and entertainment devices don't present too much load. Alternately, you can use an inverter to get the AC from the battery bank.

914Wilhelm
12-22-2013, 09:11 PM
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 could 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 it warms up but doesn't get hot.
http://i972.photobucket.com/albums/ae201/914wilhelm/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.
http://i972.photobucket.com/albums/ae201/914wilhelm/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.
http://i972.photobucket.com/albums/ae201/914wilhelm/4db99338c676c7d62fccb68248807f5b_zps4b5d19ea.jpg

I will post a wiring schematic in a bit.

914Wilhelm
12-22-2013, 09:12 PM
Edit: crazy double post!

914Wilhelm
01-11-2014, 11:00 PM
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.

http://i972.photobucket.com/albums/ae201/914wilhelm/null_zps4780fdb8.jpg

http://i972.photobucket.com/albums/ae201/914wilhelm/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.

Monarch 10ee on single phase - YouTube (http://www.youtube.com/watch?v=V3a1fdS2Efk)

Glug
01-12-2014, 12:54 PM
Very nice! Thanks for the updates.

All of these various types of drives - both as implemented by Monarch, and as retrofitted - make me wonder how they each impact lathe smoothness while cutting. And how could that be measured, especially in a quantitative way?

macona
01-12-2014, 03:48 PM
Lots of different ways to measure. Put an encoder on the spindle and you can see how smooth the spindle turns. Put accelerometers on the machine and see what the vibration is like.

This mod should not effect the lathe much, if at all. Worse case is he might loose a little top end power. The main spinde motor is DC and the spindle is driven by long belts which take up a lot of vibration.

Peter.
01-12-2014, 06:54 PM
Buy a 100k mile car and it won't be making the power it did when new. I think this conversion is brilliant, a big well-done to Wilhelm.

Doozer
01-12-2014, 07:44 PM
Hey 914Will,
Nice conversion.
Q? Can you post a summary of your work
and give the exact hookup schematic that you used
and a parts list with part numbers? That would be
really appreciated. I think I read somewhere that the
Steelman schematic had an error, or maybe it was the
patent, I don't recall. I would like to duplicate what
you did on my Hendey with the same Motor-Gen drive.
Thanks much.

--Doozer

914Wilhelm
01-12-2014, 08:49 PM
Got it running forwards and backwards at 3500rpm verified with phototachometer. Need to do some tweaking of the brush holders to get the full speed. Here's the schematic. Scale the run capacitor proportionally up or down based on horsepower. This is calculated for 4.6 horsepower. I bought the caps and relay, the heat resistant wire, the fiberglass insulating tubing and Glyptal off eBay for what it's worth. PM or publicly post should you need help locating anything.

http://i972.photobucket.com/albums/ae201/914wilhelm/e4e2e3a10c3020828b60067a1ee76696_zpsbd6a94a7.jpg

Hal
01-12-2014, 11:09 PM
Glug

Surfacefinish was always a top priorty for the EE's.

I was told that Monarch spent over a years time and a million dollars searching for the best drive belts. That is why belts are used to drive the lathe and not gears, better finish.

Hal

Glug
01-18-2014, 09:40 AM
Glug
I was told that Monarch spent over a years time and a million dollars searching for the best drive belts. That is why belts are used to drive the lathe and not gears, better finish.


I have no doubt. And that is what makes me curious about the drive aspects, beyond the belts.

This conversion, preserving the motor-generator, is really well done. I'm sure it will be more quiet once installed in the chassis, but I do wonder about alternatives. I'd really like my lathe to be silent until I turn it on. So the questions around the performance tradeoffs between the DC drive and a good VFD are important ones.

RWO
01-18-2014, 03:08 PM
A VFD operating in vector control mode driving the proper inverter-duty motor with tach feedback could provide full rated torque all the way down to zero RPM if need be, thus providing all the performance you could ask for. It would simply be a matter of selecting the appropriate motor and paying the price. Motors like that Marathon MicroMAX or BlackMAX depending on the requirements, are the type I'm talking about: http://motors.automationdirect.com/Marathon/

RWO

Doozer
01-18-2014, 03:38 PM
Even the sensorless vector mode (on my Hitachi) works super well.
On my Bridgeport I actually keep the sensorless vector mode turned
off, because if I do any power tapping, the torque is so much, it
will easily snap a tap. Even at 5 Hz.

--Doozer

lakeside53
01-18-2014, 06:34 PM
VFD and direct drive train. There are always big trade offs.

Torque is only half the problem - you still need "x" HP to remove "n" cubic inches per minute. If the required "n" is real small it doesn't matter much, but...

Torque below 60hz (USA) on a plain-Jane typical motor, with vfd driven at motor rated voltage is constant, but HP is variable. Above 60hz torque is variable (decrease with freq) but HP is roughly constant (within motor limits). OK, by messing with vfd parameters you can get back to design torque or exceed it by some amount at the bottom end, but HP is what does the work.

If I need 1hp to remove 1 cubic inch (for a given material) per minute, and I have a 5hp at the spindle at 60hz motor speed I can remove 5 cubic inches/minute; at 10hz I only have 1/6 x 5hp and I can remove 0.83 cubic inch/min. At 1hz with torque boosted to 100% (i.e. same torque at say 60hz), I only have 1/60 x 5 hp... so I can remove 0.0833 cubic inch/minute. If you exceed this amount of material removal, you are either going to trip the vfd (current) or overheat the motor. The problem at the bottom end is that relative to the power at 60hz, there isn't much hp to do serous work. If I wanted 5hp at the spindle at 10hz, I'd need a 30hp motor (+/-). You can play games with the final drive ratio such that you divide the problem between a reasonable upper frequency (say 90hz in many cases) and a reasonable lower freq (say 10hz), but a much bigger (than original) motor is the solution.



I recently went though this with exercise with a direct servo drive for a headstock.


Here was my write-up for another forum:

>>>>>

I think I have this all figured out… but I’m hoping some of you will tell me I messed up the calcs, it’s way too conservative and that have a ton of HP to spare.

We all know the varying the speed of an induction motor changes the HP or torque; basically constant torque up to the base frequency and then constant HP (i.e. torque reduces) above that.

Well… I’m converting an EMCO 11x26 lathe to cnc, and want to run the spindle with as little drive complexity as possible (like none). This lathe was originally powered with a 1hp motor, does not have a “back gear” and was originally run with elegant array of 8mm belts/pulleys The usual answer with ditching the pulleys is “go big” (hp), and maybe you have enough left over at the low speed end to be useable. The downside of big high torque/hp is tool crashes at higher speeds! The problem I needed to work though was “how much is enough”.

One way to look at it is that the original design had the full 1hp (ignoring drive train losses) available at all 8 speeds between 150 and 2200 rpm. Given the size and construction of the lathe, this HP makes sense and given that it takes about 1hp to remove 1 cubic inch of mild steel a minute, quite useable.

My first plan was to use my recently acquired new Baldor inverter rated 3hp 1760 rpm motor, but… I dug out an old (1999) 5.3hp AC servo and amp, and after a week and several conversations with the manf, finally had it running well. The Servo is smaller than the 3hp Baldor, rated at 5.3hp continuous 0-3000 rpm. It can go to 2x that for peaks. Its average torque across the entire range is 130 in/lb slightly more at the bottom and slightly less at the top. Assuming I use an HDT (or whatever) timing pulley pair to set my top spindle speed to 2200rpm, I’ll have about 3000/2200x130= 177 in/lb (before drive train losses).

But.. what does this torque really mean? Not much unless related to speed.. i.e DO I have enough torque and HP at low speeds?

One way is to determine the amount of material volume you want to remove per minute (within the rigidity constraints of the lathe) and figure the required hp.
Here's two random small lathe examples (don't sweat the material, feed rate etc choices - just examples). Using positive rake finishing type carbide at say 350 sfm, (95% drive chain efficiency)

Roughing (small lathe!) on 1.5 inch diameter mild steel 0.01 IPR, 891 rpm gives 8.91 in/minute feed rate, and 0.020 DOC results in 0.884 cu. inches removal per minute. Assuming the material is mild steel (1hp per cubic inch/minute) I’ll need 0.884 hp, and required torque is 59.4 in/lb. At 891rpm, I have about 133 in/lb. No problems. I can easily double the SFM if I want, take more DOC, increase feed etc…

Taking this to the other extreme, a 9 inch diameter work piece using 0.005 feed, mild steel, 0.020 doc, and 350 sfm (low), gives feed rate of 0.745 IPM and 149 rpm, 0.443hp and 178 in/lb torque. Hmmm… I have the torque, JUST… The good news is that I can double the SFM to 700 (feed rate now 1.592 IPM, and spindle speed 318, 0.886 hp), and I’m still right at the same max torque.

I chose mild steel as an example because it's an easy calc of 1hp per cubic in/minute. If you are turning aluminum or 4140 these numbers change radically (up and down). Carbide allows higher SFM, but does not (generally) allow very small DOC. HSS allows for very small DOC, but at much lower SFM. Run your own numbers!

In case you think I pulled the numbers from where the sun doesn’t shine, for these examples I used these two online calculators:

http://www.custompartnet.com/calculator/turning-speed-and-feed
http://www.custompartnet.com/calculator/turning-horsepower

So, assuming I did this right… it looks like I can get away with a single drive belt. A bit marginal at the low end with the chosen 2200 rpm top speed, but most of my work will be smaller and higher up speed range. I still have the “intermittent peak” rating to use if required.

>>>>>>>>>

Timleech
01-19-2014, 08:06 AM
CVA in the UK made a clone of the 10EE, but with a simple induction motor diving through a car-type multispeed gearbox in the base of the cabinet, final drive by belt as with the 10EE. Add a VFD to the motor & you have the best of all worlds.
I don't often change the gears on mine, apart from selecting back gear, but the option is there if I need full power at low speeds.

Tim