Single-phase Power for Motor-Generator 10EEs Page 1 of 7
Thread: Single-phase Power for Motor-Generator 10EEs
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03-02-2008, 08:13 PM #1
Join Date: Dec 2002 Location: Monterey Bay, Diamond California Posts: 10,260 Post Thanks / Like Likes (Given): 27 Likes (Received): 191
It is well-known that WiaD and Modular 10EEs may be powered by single-phase.
Herein I present a modification to Motor-Generator 10EEs which will allow these machines to be powered by single-phase. Both a 230 volt and a 460 volt modification are presented.
The underlying technology is adapted from Henry Steelman's U.S. Patent 2,922,942 (which see), and is extended by me to incorporate power factor correction (not claimed by Steelman in his patent) and easy adaptation to the 10EE's AC Section.
(An essential feature, and requirement of Steelman's idea is a twelve-wire three-phase motor, or a nine-wire motor which has been modified to add the three "missing" wires implicit in that motor's "star point", may be very easily powered by single phase, provided a starting circuit is provided and the motor winding components are wired in an innovative way. This innovation simulates a capacitor start/capacitor run single-phase motor. I have added power factor correction, which Steelman did not claim, and which further improves upon Steelman's idea).
The first Figure describes in the abstract how a three-phase motor may be powered by single-phase without sacrificing motor power. This is more-or-less directly from Steelman's patent, extended by information included in Steelman Industries, Inc's modification to that patent for 460 volt applications.
The second Figure describes the 10EE AC Section, with all loads except for the "three-wire control station" removed, and with each terminal to which the converted motor and its support circuitry is to be connected.
The third Figure shows details the 230 volt modification, showing how each part of the motor-generator, and the additional starting and power factor correcting circuits are to be integrated into the AC Section. The 90-66 potential relay coil is across the entire start winding. The run windings are split across two poles of the magnetic motor starter thereby reducing the stress on the Size 1 starter. There are two power factor correcting capacitors, corresponding to each pole of the starter. As is required by the NEC, the capacitors are placed after the disconnecting means, and before the motor protection means. Bleeder resistors are not shown for clarity.
The fourth Figure shows details the 460 volt modification, showing how each part of the motor-generator, and the additional starting and power factor correcting circuits are to be integrated into the AC Section. The 90-66 potential relay coil is across one-half of the start winding. Each capacitor shown is actually two identical capacitors in series.
I have not detailed the values of the capacitors. Clearly, the run capacitors must be 370 VAC, minimum (740 volts when placed in series for 460 volts), and the start capacitors must be 250 VAC, minimum (500 volts when placed in series for 460 volts).
Initial values for C may be obtained from
I = 2 * π * F * C * V
where I is the FLA in Amperes, π is the constant 3.14, F is the frequency in Hertz (the factor 2π converts this frequency from Hz to radians/second), C is the capacitance in Farads, and V is the voltage in Volts.
Final values for each C may be obtained by tuning.
References:
1) Henry A. Steelman's patent
http://www.pat2pdf.org/patents/pat2922942.pdf
2) Steelman Industries Inc installation information for Steelman's H.A.S. converter
http://www.capacitorconvertors.com/p...structions.pdf
Recommended initial values for Cr are 11.53 µF per FLA amp for 230 volts and 5.77 µF per FLA amp for 460 volts. Use a clamp meter to ensure the current in the start winding doesn't exceed FLA amperes.
Recommended initial value for Cs is ten times the value of Cr, tuning for starting in two seconds or less.
Recommended initial value for Cpf is 0.1 times the value of Cr, tuning for just under minimum current, on the under-compensated side of 1.0 P.F.
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Last edited by peterh5322; 03-03-2008 at 12:20 PM.
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03-08-2008, 12:57 AM #2
Join Date: Oct 2004 Location: LeClaire, Ia Titanium Posts: 2,942 Post Thanks / Like Likes (Given): 42 Likes (Received): 293
Way Cool!
Peter- this is way cool!!!
I was originally planning on 10hp VFD with backgear... at the moment, I'm working on the J-head 56C VFD project right now, but when I get it done (on both the radial drill AND the BRJ), I'll try this out on my '42 MG system.
Thanks!!!
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03-08-2008, 09:05 AM #3
Join Date: Dec 2002 Location: Monterey Bay, Diamond California Posts: 10,260 Post Thanks / Like Likes (Given): 27 Likes (Received): 191
"Peter- this is way cool!"
Thanks.
I have also designed a similar modification for Monarch engine and toolroom lathes with geared reversing heads, such as the Series 61, and which will allow those machines to be powered by single-phase as well.
One limitation on those machines, which doesn't exist on the 10EE, is the presence of a reversing magnetic starter, and which may limit such single- phase conversions to the lower range of motor horsepower when powered by 230 volts, but which limitation may not exist when powered by 460 volts. This limitation comes down to the motor horsepower and the single-phase horsepower rating of the starter, hence its NEMA size designation.
Last edited by peterh5322; 03-08-2008 at 02:16 PM.
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03-09-2008, 08:48 PM #4
Join Date: Sep 2002 Cal Haines Country: UNITED STATES Titanium State/Province: Arizona Posts: 3,098 Post Thanks / Like Likes (Given): 575 Likes (Received): 274
Hi Peter,
Thanks for posting this! This is a very exciting and interesting concept.
Do you have this working on an MG machine? Where do you suggest mounting the start circuit relays and the capacitors?
Cal
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03-09-2008, 11:11 PM #5
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"Do you have this working on an MG machine?"
Not at the present time.
It is next on my "to do" list.
"Where do you suggest mounting the start circuit relays and the capacitors?"
In an enclosed box (Hoffman, or equal), mounted above the spindle motor and backgear.
There are spare threaded bores (1/2" electrical trade size) within the C-H starter compartment from which a length of flex can be routed to the box.
Also, a length of flex would be routed from the M-G unit to the box.
The contents of the box would be: the P.R. and the auxiliary starting contactor (I don't trust the 90-66 with a 6+ HP starting load, besides the way I have designed the modification it is good for 230 and 460 volts, and not just 230 volts), and all caps with their bleeders.
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03-10-2008, 01:34 PM #6
Join Date: Sep 2002 Cal Haines Country: UNITED STATES Titanium State/Province: Arizona Posts: 3,098 Post Thanks / Like Likes (Given): 575 Likes (Received): 274
Thanks Peter,
I don't have a coolant pump, so that space is another option to mount the Hoffman box.
I assume that the currents through OL1 and OL2 will be different, and heaters will need to be adjusted accordingly?
Cal
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03-13-2008, 02:05 AM #7
Join Date: Dec 2002 Location: Monterey Bay, Diamond California Posts: 10,260 Post Thanks / Like Likes (Given): 27 Likes (Received): 191
"I assume that the currents through OL1 and OL2 will be different, and heaters will need to be adjusted accordingly?"
Indeed so.
About 1/2 of the run winding for the start/run winding.
That's one good thing about the old two-overload starters, each side is independently changeable.
The Steelman manual gives suggested values for FLA vs. HP, and also a way of computing the overload current setting vs. FLA.
If you have coolant, the same converter concept would work there, too, only on a much smaller scale, 0.33 HP vs. 6+ HP.
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03-13-2008, 02:05 PM #8
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FWIW, on many machines with a B&S 200 coolant pump, the motor is an ordinary NEMA 56C motor, and these are available in single-phase, just as the B&S 200 pump was available in single-phase.
The coolant pump compartment isn't tall enough to house a B&S 200 single-phase pump, though, although you could detach the starting capacitor and mount it elsewhere.
Buying a 1/3 HP single-phase NEMA 56C motor locally (or from Surplus Center) will probably cost less than duplicating the conversion for the original B&S pump motor, although if you're doing the 9-wire to 12-wire conversion yourself it would remain an economical option.
(If you operate the M-G from a Cedarberg 7.5 HP heavy duty static ... no longer available, I'm told ... as Donie did for quite a while, the three-phase which is generated by the M-G could be back-fed into the coolant pump circuit, and then used to operate the coolant pump motor on internally manufactured three-phase).
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03-28-2008, 06:06 PM #9
Join Date: Dec 2002 Location: Monterey Bay, Diamond California Posts: 10,260 Post Thanks / Like Likes (Given): 27 Likes (Received): 191
Here's a clearer version of the second diagram of
Single-phase Power for Motor-Generator 10EEs
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07-10-2008, 08:25 PM #10
Join Date: Jun 2008 dgfoster Location: Bellingham, WA Titanium Posts: 3,525 Post Thanks / Like Likes (Given): 828 Likes (Received): 1681
"An essential feature, and requirement of Steelman's idea is a ....a nine-wire motor which has been modified to add the three "missing" wires implicit in that motor's "star point", may be very easily powered by single phase...."
Peter or anyone who has tried this: I recently consulted a local reputedly knowledgeable motor rebuilder about converting my newly acquired 1943 EE MG unit from 3-phase to single-phase 220 power. Mine is a nine-wire motor (I think). He advised me that adding the three wires was no small undertaking. It would require disassembly of the MG unit and heating the windings to soften the varnish and separate the wiring and then a fair bit of work to find the correct windings and then add in the additional three wires. Sounded like this process might easily cost 1K and likely more. Does this sound like correct information?
How can I be sure my motor is a nine-wire motor and not a twelve-wire?
I was hoping to avoid the expense of a phase converter.
This is my first post to this group. I hope I am following proper procedure. Any advice is sincerely appreciated.
Denis
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07-10-2008, 11:49 PM #11
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"How can I be sure my motor is a nine-wire motor and not a twelve-wire?"
They're all nine-wires.
There is a star-point in there, somewhere, with the three wires twisted together and brazed, then insulated.
The Steelman concept is dependent upon access to that star-point.
But, a 7.5 HP "heavy duty static" also works with an M-G model, and that doesn't require access to the star-point.
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07-11-2008, 12:52 AM #12
Join Date: Jun 2008 dgfoster Location: Bellingham, WA Titanium Posts: 3,525 Post Thanks / Like Likes (Given): 828 Likes (Received): 1681
Peter,
Thanks for your very quick reply.
Sorry I am so dense, but is that star point likely located in the box pictured at the following URL? http://s349.photobucket.com/albums/q...DSCF5344-1.jpg
Or is it buried in the motor imbedded in varnish and not a little bit of grease? I can see some wires wrapped together and laying beneath wires heading to GS1, GS2, GA1, and GA2. Maybe this is the star point you are referring to? I think you are referring to a connection within the motor case--I just want to be sure I understand correctly.
Incidentally, I did try to Google "star point" in electrical terminology but did not find much that was helpful.
Denis
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07-11-2008, 04:14 AM #13
Join Date: Jun 2006 macona Location: Beaverton, OR Diamond Posts: 5,459 Post Thanks / Like Likes (Given): 0 Likes (Received): 49
The star point will be inside the motor. Like the motor guy said, you got to go inside to find the junction where the leads come together.
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07-11-2008, 11:19 AM #14
Join Date: Jun 2008 dgfoster Location: Bellingham, WA Titanium Posts: 3,525 Post Thanks / Like Likes (Given): 828 Likes (Received): 1681
Well, that finishes the idea of rewiring the motor. It would cost way too much and I would still be wondering if the motor would fail for some age-related reason a few weeks or months later.
So, I think my next option would be to consider a rotary phase converter. If anyone has any pointers on how to choose a quality converter I would appreciate it. I think I can get one for about 425 with shipping. That would be for a cast iron TEFC motor and panel box with necessary caps.
Thanks, Denis
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07-11-2008, 11:27 AM #15
Join Date: Mar 2007 Peter Miles Location: Lake Forest Park, Cast Iron WA Posts: 341 Post Thanks / Like Likes (Given): 0 Likes (Received): 2
Denis,
PNW is not a very descriptive location, but assuming that it means Pacific North West, you might try Eylander Electric in Everett, WA. They've been building them for a long time. I bougth several from them (migrated to larger sizes) during the late 1980's and early '90s.
They are still there and making them. They are a full motor shop as well, so you might ask them about going into your MG set.
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07-11-2008, 12:45 PM #16
Join Date: Jun 2008 dgfoster Location: Bellingham, WA Titanium Posts: 3,525 Post Thanks / Like Likes (Given): 828 Likes (Received): 1681
Thanks, Peter.
I am just one hour north of you.
Denis
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07-11-2008, 01:10 PM #17
Join Date: Dec 2002 Location: Monterey Bay, Diamond California Posts: 10,260 Post Thanks / Like Likes (Given): 27 Likes (Received): 191
On a nine-wire machine, including a 10EE M-G, I would expect to see the three wires, which would be labeled T10, T11 and T12, if these were brought out, twisted and brazed, then insulated and laced down to the set of coils before varnishing.
When wiring a nine-wire motor for low voltage, 230 in this case, you actually have two star-points, one which is internal to the motor, and another which you create by connecting T4, T5 and T6 together and insulating these.
Then, you connect T1-T7, T2-T8 and T3-T9, and, as always, connect T1, T2 and T3 to the line.
So, for the Steelman method, you have to open up the motor, identify and isolate what would be T10, T11 and T12, and then bring these out as independent leads.
Steelman's patent shows only two being brought out, and that is indeed the minimum required for his method, but bringing all three out is a more general solution, and allows for greater flexibility, including the 230 and 460 single-phase adaptations which I described earlier.
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07-11-2008, 03:35 PM #18
Join Date: Jun 2008 dgfoster Location: Bellingham, WA Titanium Posts: 3,525 Post Thanks / Like Likes (Given): 828 Likes (Received): 1681
Thanks Peterh,
I would love to try the opening the motor and isolating the leads if this were something I could do myself. But it sounds like it would require special equipment to do this job. http://www.practicalmachinist.com/vb/monarch-lathes/single-p... 10/10/2017 Single-phase Power for Motor-Generator 10EEs Page 7 of 7
From a cost and time perspective, I think I will go with a rotary converter. That is an off-the-shelf solution that will not cost as much as the expense of the work being done in a motor shop and will be much quicker too. If, for some reason, the MG set is not functional when I power it up, I can sell the converter and then I would just put in a VFD setup. I was told the MG unit was working just fine when the machine was "unplugged" a couple of weeks ago.
I am very appreciative of you providing the information about the Steelman method and your refinements of it. I had no idea this was possible and most of the people I have consulted about my problem have not been aware if it either.
Denis
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07-11-2008, 08:08 PM #19
Join Date: Jun 2006 macona Location: Beaverton, OR Diamond Posts: 5,459 Post Thanks / Like Likes (Given): 0 Likes (Received): 49
I dont think you would need special tools short of a socket wrench and sockets. The junctions are made inside of either fish paper or fiberglass tubing. Its just a matter of finding the tube with the three wires you need and bringing them out. Ideally you should use a silphos brazing rod to do the connections but you can get away with normal rosin core solder.
If varnish is in the way you could heat the area with a heat gun to soften it.
I am going to be looking at a surface grinder sometime next week and if I get it I may look into doing this mod to the motor.
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07-11-2008, 10:26 PM #20
Join Date: Nov 2004 Location: Webster Groves, Diamond MO Posts: 5,911 Post Thanks / Like Likes (Given): 1397 Likes (Received): 2241
MG 12 wire conversion
My manual for my MG EE doesn't say anything about about changing voltage, but it came from a US Navy base and is set up for 208 VAC, which for some reason the military seems to love, so it may be atypical. Assuming the unit is a nine wire one, getting to the star point wires should not be too challenging, considering how open everything is. Judging by the work I see posted on this forum, the conversion should be well within the skill range of most of the contributors. Probably the most work would be pulling the unit out of the lathe and getting to the windings. I know of an MG that a shop replaced with an AC drive. If I get time and the owner agrees, I may open it.
Re phase converters, they are mostly just capacitors, sometimes with a motor that idles on the line to improve phase balance. One of my friends (who doesn't want to be identified because of concerns that someone may start a fire) has been using them for years and says that 40 mfd, between one side of the single phase and the third leg, per horsepower is a good starting point. More may be needed for starting the idle motor and then switched out after it reaches near running speed. The idle motor should be larger than the working motor and started first. Since the MG runs continuously, an idle motor may not be necessary. The capacitors should be oil filled motor running capacitors, not electrolytic starting ones, of course rated well above the peak voltage, which is 1.414 times the nominal voltage. I have had two phase converters, one a simple switched capacitor unit on a Bridgeport sized mill and the other a RotoPhase one with a motor. Both worked, but neither delivered full power. If I had to have one again, I would not spend the money for a commercial one.
Bill
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07-12-2008, 01:50 AM #21
Join Date: Jun 2008 dgfoster Location: Bellingham, WA Titanium Posts: 3,525 Post Thanks / Like Likes (Given): 828 Likes (Received): 1681
With Bill and Macona's posts this decision may not be so open and shut on my part. I guess I was intimidated by the motor guy showing me the special baking oven in which he heats the windings of a motor he is preparing for repair (to soften the varnish) and telling me that it can really be "the s***s" trying to trace down and isolate the appropriate windings and leads without having the aging insulation crumble and otherwise misbehave.
How would I, as a beginner, consider such “major” operation if an old pro finds it tough?
I will try to learn more about the capacitor phase converter idea as well. Maybe there is a non-store-bought solution yet.
I do appreciate the information so many have already provided.
Denis
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Seen this ad Ad was Not interested Ad covered multiple times inappropriate in this ad content
07-12-2008, 03:23 AM #22
Join Date: Jun 2006 macona Location: Beaverton, OR Diamond Posts: 5,459 Post Thanks / Like Likes (Given): 0 Likes (Received): 49
The old timer may be calling it tough because of three possibilities.
1. It really is tough 2. He dosnt want to deal with it. 3. To justify how much he is going to charge you.
Cant hurt to poke around a bit.
The monarchs are not true switchable 230/460. They are set up for one or the other at the factory. They can be switched though with little trouble. The MG itself is a 9 wire three phase motor so thats the easy part. The hard part is the coil on the main contactor. You need to either fine the right voltage coil or install a little 230-460 transformer to get the right voltage to drive the coil.
When I got my 10EE there was a small (50VA) 230-460 transformer in the coolant pump area and I couldnt figure out what the heck it was for until later when I figured that the machine must have been reconnected for 460v use.
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07-12-2008, 12:02 PM #23
Join Date: Sep 2002 Cal Haines Country: UNITED STATES Titanium State/Province: Arizona Posts: 3,098 Post Thanks / Like Likes (Given): 575 Likes (Received): 274
Denis,
There's no reason you can't build your own rotary phase converter if you are comfortable doing your own wiring. You can often pick up a 5 to 7.5 HP three-phase motor for less than $100, often $10 per HP. The rest of the parts are readily available both new and surplus. Here's the forum where the phase -converter experts hang out:
http://www.practicalmachinist.com/vb...splay.php?f=11 Cal
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#24 Join Date: May 2003 Location: Walla Walla Wine Diamond and Wild Turkey Posts: 4,264 Post Thanks / Like Likes (Given): 0 Likes (Received): 113
I ran a MG EE for many years with a 7 1/2hp static phase converter. The only problem was starting the machine at spindle speeds over 900rpm, the machine would surge as the MG pulled down and the exciter voltage would drop, causing the switch to disengage, the machine would run full speed after starting. I later used another MG set that had a bad DC end, that is, I used the AC motor end as a rotary and started it with the static converter, and then ran the EE and other machines off it. The static converter was a Cedarburg kit. I cant seem to find them now, but, this guy has a kit for $71 and appears to have them on ebay for the same. http://www.wnysupply.com/index.cfm/f...arentcat/25260
What I would do now is, get the 10hp static kit, and pick up a 10hp 3phase motor used. My local scrapper has several. If you want to get by on the cheap, just the static converter will get you there anyway.
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07-12-2008, 08:06 PM #25
Join Date: Jun 2008 dgfoster Location: Bellingham, WA Titanium Posts: 3,525 Post Thanks / Like Likes (Given): 828 Likes (Received): 1681
Donie and Cal,
I am going to pursue making my own converter. The links you have provided are very helpful. I have waffled with the idea of pulling the MG unit and finding the wires etc. as instructed. I think the Rotary Phase Converter is the more practical approach for me at my skill level. I have no concerns about putting together switches and caps etc as long as I have very clear directions as to what to do. So, right now I am in the market for a good used TEFC 5 or 7.5 hp 3-phase motor. Once I locate one, I will then order the appropriate caps etc as a kit and put it all together. (Unless I change my mind...... again :-) )
Denis
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07-14-2008, 11:35 PM #26
Join Date: Nov 2004 Location: Webster Groves, Diamond MO Posts: 5,911 Post Thanks / Like Likes (Given): 1397 Likes (Received): 2241
MG 12 wire conversion
I got a look at the MG I mentioned in an earlier post. It is in an overhead storage area so I had to climb up with a flashlight. The covers were off both ends and I didn't have to take any tools. All I could see was a typical set of varnish impregnated three phase windings. The wires come out of the other end of the windings at the juncture of the motor and generator, so the two would have to be split apart. The star point is almost certainly next to the leads and would be accessible after the separation. As Macona pointed out, all you would need is a heat gun, available from WW Grainger, etc. I have several ovens capable of heating the stator, but I wouldn't bother with them and would prefer to use the heat gun. Identifying the different windings is easy, just cut the star point apart and check continuity to the other marked leads. I would have no qualms about tackling the job. I think the person who quoted up to 1K was mostly practicing CYA.
Re phase converters, you could make an efficient one with a synchronous motor or a three phase generator run as a motor. You would probably have to pony motor the generator up to speed, then turn the DC field on to lock it to the line, but then you would have good conversion, better than a normal induction motor would give, but of course the problem is finding the synchronous motor or generator. Because getting three phase to a streetcar requires two trolleys, some of the old streetcars used a single phase synchronous motor with a DC excited armature and a second set of stator coils that produced two phase, 90 degrees apart instead of 120 like three phase, and fed that to a Scott connected transformer to make three phase. I don't know why they didn't go straight to three phase from the motor, but it must have worked. I have 5 HP and 10 HP motors you could have for carrying them away, but shipping from St. Louis is probably more than either is worth. If I have time, I might try setting the 10 HP one up as a converter, just for entertainment. It is a huge old piece of cast iron that would have a lot of inertia for dealing with starting surges. Still, nothing beats a 200 amp three phase line.
Bill
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07-15-2008, 01:31 AM #27 http://www.practicalmachinist.com/vb/monarch-lathes/single-p... 10/10/2017 Page 3 of 7
Join Date: Jun 2008 dgfoster Location: Bellingham, WA Titanium Posts: 3,525 Post Thanks / Like Likes (Given): 828 Likes (Received): 1681
Going a little further
Bill,
Thanks for your thoughtful reply and "attic research."
You touched on a couple of points that I would like to invite you to expand upon.
One is the idea that the winding leads are accessible between the two stators so "so the two would have to be split apart." My question is how are the stators connected to the housing? I suppose they are simply bolted in place. So once the rotor assembly was pulled out, then the stator of the motor would be unbolted and slid out. As one is doing this the leads would have ot be carefully fed back into the housing. This would likely pose no special problems? Would you expect the 65-year-old insulation to still be flexible enough to put up with the manipulation? Or might it start crumbling and that would not be so good? I have zero experience opening up old motors of this vintage.
In the remarks about the rotary converter you mentioned large inertia of the converter as an advantage in dealing with the surge associated with starting the machine motors. How much of an issue is this likely to be if one uses a common ( I think they are usually synchronous type if they specify the rpms-- right?) say 7.5 hp 1725 rpm 3-phase TEFC motor for the converter? I would guess I would usually be starting my lathe at relatively low RPMs and then ramping up to speed over the course of a few seconds. At least that is the way I have used my current bench lathe. I am more inclined at the present to make a converter by putting together a panel kit and hooking it to a 3-phase motor, but I have no experience with such a system. It sure helps to "talk this over" before jumping in.
I appreciate your kind offer of the old motors. I wish I were not located so far from you. I would definitely take you up on that. Be nice to meet you in person besdes.
Denis
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07-15-2008, 03:35 PM #28
Join Date: Jun 2006 macona Location: Beaverton, OR Diamond Posts: 5,459 Post Thanks / Like Likes (Given): 0 Likes (Received): 49
I had two MG units here. Both the same age. One had rubber insulated wire and it was still pliable. The other was the cloth covered and it cracked if you looked at it wrong. You could just install new flying leads while you have it apart if that is the issue.
One bad things about RPCs is they can suck more power...
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07-15-2008, 05:42 PM #29
Join Date: Dec 2002 Location: Monterey Bay, Diamond California Posts: 10,260 Post Thanks / Like Likes (Given): 27 Likes (Received): 191
My eldest, a '45, has all thermoplastic insulation, as does my youngest, a '56.
Cloth-covered rubber leads were common on war-baby machines.
I suppose it varied with the manufacturer, and to what "price-point" he was building.
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07-16-2008, 02:28 PM #30
Join Date: Jun 2008 dgfoster Location: Bellingham, WA Titanium Posts: 3,525 Post Thanks / Like http://www.practicalmachinist.com/vb/monarch-lathes/single-p... 10/10/2017 Page 4 of 7
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Thanks, Macona and Peterh,
So, It sounds like there is a good chance my '43 has cotton/rubber leads. The term flying leads is new to me and I figure this means the wire that I assume is sil-phos soldered to the winding and is usually held in place by the "varnish" on the winding assembly. I would suppose the varnish that is used is a special varnish that can be purchased from some specialty supply houses.
The reader may have noticed there are a whole lot of "figures" and "supposes" in my post. If anyone can fill in those blanks for me I would appreciate it.
Denis
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07-16-2008, 06:29 PM #31
Join Date: Dec 2002 Location: Monterey Bay, Diamond California Posts: 10,260 Post Thanks / Like Likes (Given): 27 Likes (Received): 191
My local motor shop always Sil-Phos brazes the magnet wire to each other, and to the external leads.
The process of isolating the star-point is not rocket science, but it does require patience and care.
Steelman Electric Service once had a brochure detailing how to modify 9-lead motors for its 12-lead converters. Perhaps it still does.
An interesting factor is a 9-lead motor connected to a static can achieve a maximum of 67 percent of nameplate HP, but a 12-lead motor connected to an H.A.S. static can achieve at least 90 percent of nameplate HP.
Steelman sells a lot of converters to the oil service, irrigation and related trades, where there are lots of isolated single-phase installations.
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07-17-2008, 05:02 PM #32
Join Date: Dec 2002 Location: Monterey Bay, Diamond California Posts: 10,260 Post Thanks / Like Likes (Given): 27 Likes (Received): 191
"The monarchs are not true switchable 230/460"
The U.S. Navy 10EEs were switchable.
This results in these separate types of 10EEs, not all of which were available with every drive type:
1) 230/460 with heater change only (M-G and probably Sunstrand),
2) 550/575/600 (M-G),
3) 230 only (230/460 for anode transformers, but 230, only, for filament transformers; WiaD and Modular),
4) 460 only (460/230 for anode transformers, but 460, only, for filament transformers; WiaD and Modular),
5) 230/460 (230/460 for anode and filament transformers; WiaD and Modular; U.S. Navy, only),
Note that the very few 10EEs which reached Europe most probably are 380/400/415.
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07-17-2008, 11:21 PM #33
Join Date: Nov 2004 Location: Webster Groves, Diamond MO Posts: 5,911 Post Thanks / Like Likes (Given): 1397 Likes (Received): 2241
MGs, motors, and voltages
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Denis,
Looking at the generator end of the MG, there is the cast end frame, a cylindrical housing about 8 in long, which holds the generator windings, then a little larger in diameter and much longer housing for the motor coils that you want to get to, which also holds the terminal box on the side. If the two housings can be separated, then the generator leads would need to be slid out carefully and the motor leads would stay where they are. At this point, all I can tell you is that the bolts mounting the end frame do not go through to the larger housing. Looking at the MG which is still in my lathe, I can't tell if the housings are one or two pieces, but logic says that they are two since turning out a stepped unit would be more work than bolting them together. Next time I get to the shop with the "attic unit", I can see if there are bolts from the other end. As to old insulation, I often slip silicone coated fiberglass sleeving over them, using sleeving large enough to go over terminals, if attached. I realize that this is "ne kulturney" to a purist, but it causes the minimum disturbance to the windings and works well.
If you are lucky, the star point leads will be on the outside of the wires tied to the ends of the coils, otherwise you will have to find them and work them out in the open. As to brazing the new leads, if you are good with a torch, that certainly is better, but soft solder melts about 450F and if the coils get hot enough to melt it, they are toast anyway, so I wouldn't be concerned about a good soft solder joint.
Re rotary converters, synchronous motors have a permanent or electromagnet in the armature that locks onto the rotating magnetic field generated by the coils. They rotate at 60 turns per second or an even fraction like 30 or 20, which translates to 3600, 1800, 1200 RPM, etc. Almost all common motors are induction types that generate their own armature magnets by the rotating magnetic field passing shorted bars in the periphery of the armature. To do that, they must always be falling behind a little, known as "slip". they will never quite reach synchronous speed and will typically run at 3450, 1750, or 1150 RPM. Since we are counting on the armature magnetism to generate the extra phase, they will not do as clean a job as a permanent or electromagnet. A generator is almost the same as a synchronous motor and they can be interchanged except that the generator run as a motor will need to be brought up to speed somehow before it can lock in. Since energy is being sucked out of the armature to power the extra phase, more mass will make it supply starting surges better. I have not tested the theory, but I suspect that a big old heavy motor will work better than a modern lightweight one. In a sense, you go to the larger motor for more mass and lower losses in coil resistance, etc. rather than horsepower, which you are not really using.
Bill
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07-20-2008, 11:20 AM #34
Join Date: Jun 2008 dgfoster Location: Bellingham, WA Titanium Posts: 3,525 Post Thanks / Like Likes (Given): 828 Likes (Received): 1681
Thanks
My thanks to Peter and Bill.
I am starting to get a better handle on this issue. I am, for the present, working on the phase converter approach. I am looking for a 7.5 to 10 HP 3-phase motor. It sounds like it is the electrical capacity of the bigger motors and not their physical mass that is advantageous. Based on one of Bill's earlier posts concerning inertia of a large motor tending to reduce startup surge issues
“. It is a huge old piece of cast iron that would have a lot of inertia for dealing with starting surges"
I had considered adding a flywheel to the converter in order to increase its moment of inertia. It would be an easy task to put one on the motor shaft. But I have shelved that idea.
It is interesting how many "fields" (can't avoid the so-to-speak comment) just the beginning exploration of the EE restoration and use leads to. Good stuff.
Denis.
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07-20-2008, 02:10 PM #35
Join Date: Sep 2002 Cal Haines Country: UNITED STATES Titanium State/Province: Arizona Posts: 3,098 Post Thanks / Like Likes (Given): 575 Likes (Received): 274
FWIW, I have a 7.5 HP rotary phase converter. My 10EE draws about 100 amps for the first second or so as the MG starts, then it drops back to less than 6A at idle (I forget the exact value). That's a pretty good surge but it does not dim the lights or trip the 30A breaker that the RPC is connected to, but it's enough to blow a 20A slow-blo fuse. Cal
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07-24-2008, 09:08 PM #36
Join Date: Jun 2008 dgfoster Location: Bellingham, WA Titanium Posts: 3,525 Post Thanks / Like Likes (Given): 828 Likes (Received): 1681 http://www.practicalmachinist.com/vb/monarch-lathes/single-p... 10/10/2017 Page 6 of 7
7.5 HP Motor
Thanks for your input,Cal. It is nice to know what peoples' "real world" experience is. With all the information in hand from you and the other people who responded, I have located a 7.5 TEFC rebuilt motor and a panel kit. I hope that I will be powering up my lathe (finally) by the end of next weekend.
Denis
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03-17-2009, 03:33 PM #37
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Instructions for 12-Wire Conversions
Motor Modifications For a 230/460 Volt, Single Speed, 9 Lead, 3 Phase Motor (Extracted From H.A.S. Document *)
Step 1. After removing the rear end bell of the motor, the point in the winding that was formed by joining the three internal ends of the three phases together must be located. This point is commonly known as the "Star Point", as indicated in the figure Step 1 [ * ] . It is readily identified by three wires or groups of wires in individual sleevings joined together electrically and mechanically inside the motor winding.
Step 2. After the Star Point is located, the three ends are then separated. The ends of the nine motor leads are also separated, so that no two ends are touching (for testing purposes). Care must be exercised when two and four circuit windings are encountered, as these sometimes have more than three ends joined together to form the Star Point. All ends must be separated.
By using an ohmmeter or test light, the Star Point end or ends, that show continuity to motor lead #7 should be located and a length of motor lead wire attached to this end, or ends, and permanently marked as motor lead #10. The end of # 8 should be located, and a lead wire attached (in the same manner) and permanently marked as motor lead #11. The end of #9 should be located and a lead wire attached (in the same manner) and permanently marked as motor lead #12.
This completes the modification of the motor as shown by the diagram above marked Step 2 [ * ] . The three additional leads are brought out into the motor connection box resulting in a total of 12 leads emerging from the motor winding.
[ * ] Refer to the H.A.S. document "staticinstrictions.pdf" for the figures.
Last edited by peterh5322; 03-18-2009 at 01:51 PM.
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03-21-2009, 08:42 AM #38
Join Date: Jul 2001 Country: UNITED STATES Stainless State/Province: North Carolina Posts: 1,829 Post Thanks / Like Likes (Given): 123 Likes (Received): 320
http://www.capacitorconvertors.com/p...structions.pdf
Here you go, from the Steelman site. --Doozer
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03-21-2009, 01:01 PM #39
Join Date: Dec 2002 Location: Monterey Bay, Diamond California Posts: 10,260 Post Thanks / Like Likes (Given): 27 Likes (Received): 191
Yes, that document, the related USPTO document, and the relevant formulae were disclosed in the very first page of this thread, here:
http://www.practicalmachinist.com/vb...46&postcount=1
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03-05-2010, 04:47 PM #40 http://www.practicalmachinist.com/vb/monarch-lathes/single-p... 10/10/2017 Page 7 of 7
Join Date: Nov 2006 Bob-J-H Location: Camarillo Ca Cast Iron Posts: 330 Post Thanks / Like Likes (Given): 1 Likes (Received): 49
Steelman motor experiment
I thought it might be interesting to some to learn the results of some testing I did with a 3 hp motor. At FLA run on a RPC torque was 10 Ft LBS. Wired to a static with with 72MF run cap. 9 ft.lbs. Modified per Steelman with 72MF run cap. 10 ft lbs. Torque was measure with a prony brake. 10 lbs of torque at 1765 RPM translates to 3.3 hp. A single phase motor of the same hp put out the same FLA torque. The locked rotor torque was much higher. Bob
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03-05-2010, 06:38 PM #41
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"... At FLA run on a RPC torque was 10 Ft LBS. Wired to a static with with 72MF run cap. 9 ft.lbs. Modified per Steelman with 72MF run cap. 10 ft lbs ..."
So, 100 percent of nameplate, just as Steelman claims.
Great work!
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03-08-2010, 04:35 PM #42
Join Date: Nov 2006 Bob-J-H Location: Camarillo Ca Cast Iron Posts: 330 Post Thanks / Like Likes (Given): 1 Likes (Received): 49
Steelman modified motor
Hello Peter, While true the motor put out 3.3 hp after being modified per Steelman. The same motor put out 3 hp without being modifed and run on a static converter.( some other observations) Less starting capacitance was needed after being modified. 200 vs 300. When run caps were devided between ABC, torque went down. Perhaps you could explain your formula for figuring capacitance after being modified.maybe an example. By the way I used to live in Pacific Grove, while at Ft. Ord. Bob
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04-02-2010, 12:34 PM #43
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The formula ...
I = 2 * π * F * C * V
... comes from the fundamental relation of current to frequency, capacitance and voltage.
One generally knows the FLA rating of a motor, assuming the name plate is still intact.
The frequency is usually 60 Hz (North America and western Japan), except where 50 Hz is employed (the rest of the World and eastern Japan).
The voltage is, of course, a national average, usually 240 or 480 for North America.
(2 * π = 6.28, and this constant converts from Hz to radians per second).
Solving for C, we have ...
C = FLA / ( 6.28 * 60 *240 )
... in farads, or ...
C = ( FLA / ( 6.28 * 60 * 240 ) ) * 10^6
... in µF.
C is a staring point, and the objective is to "tune" for I = FLA amps, without exceeding FLA amps. A clamp-type amp meter is quite helpful here. Fluke, or equal.
Steelman's instructions are a guide, too, as the current setting for each overload (main/run and quadrature/start) are provided as a function of motor HP.
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05-05-2010, 11:30 AM #44
Join Date: Nov 2006 Bob-J-H Location: Camarillo Ca Cast Iron Posts: 330 Post Thanks / Like Likes (Given): 1 Likes (Received): 49
Thank you Peter. Bob
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11-26-2013, 01:46 PM #45
Join Date: Dec 2002 Location: Monterey Bay, Diamond California Posts: 10,260 Post Thanks / Like Likes (Given): 27 Likes (Received): 191
Please see ...
Converting Monarch 10ee motor-generator 3-phase to single phase, Steelman method
... for a complete series of photos by another researcher on splitting the M-G's "Y-point" in order to enable accessing T10, T11 and T12 for the Steelman method.
Actually, only T12 and T10+T11 is required, without loss of the ability to use the M-G in either conventional or Steelman configurations.
When using the Steelman method, T10+T11 would be insulated and not used, and T12 would be brought to the start+run circuit.
When using the conventional method, T10+T11 would be connected to T12.
Only T12 is required if the M-G is to be limited to only the Steelman configuration.
Peter
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02-02-2015, 02:55 PM #46
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Henry Steelman's U.S. Patent 2,922,942 (January 26, 1960) is available for download. Pat2PDF.org is one suggested method of downloading.
Steelman, knowingly or unknowingly, made some errors in his drawings, and in his numbering of certain parts of his inventive device.
Whereas, in Figure 2 the "A" phase is correctly labeled 1, 4, 5 and 2, the "B" and the "C" phases are numbered inconsistent with NEMA standards.
Whereas NEMA would have the "B" phase numbered 7, 10, 11 and 8, Steelman elected to number this phase 7, 11, 11 and 8.
And, whereas NEMA would have the "C" phase numbered 3, 6, 9 and 12, Steelman elected to number this phase 3, 6, 9 and 10.
Essentially, Steelman arbitrarily imposed a non-NEMA numbering system, one which is certainly consistent with the stated purpose of his inventive device, but which leads to possibly considerable confusion to those who are of a "NEMA mindset".
It is true that 12-wire motors actually exist. But, it is also true that 11-wire motors do not!
It is also true that Steelman's inventive device only needs 11 of those 12 wires, and a possible consequence of his mindset is his patent disclosure shows an 11-wire motor, not the more standard 12-wire motor.
Once this apparent anomaly in understood, Steelman's patent disclosure may be more fully appreciated.
Also, Steelman apparently did not have access to more modern potential relays, such as the 90-66 and similar relays, in which the voltage rise across the http://www.practicalmachinist.com/vb/monarch-lathes/single-p... 10/10/2017 Page 3 of 3
entire "quadrature" winding is sensed. Therefore, Steelman apparently elected to sense the voltage rise across only one-half of the "quadrature" winding.
If a 90-66 were to be employed, as is our present practice, the voltage rise across the entire "quadrature" winding would be sensed for 240 volt applications, and the voltage rise across only one-half of the "quadrature" winding would be sensed only for 480 volt applications, using the same 90-66.
Last edited by peterh5322; 02-04-2015 at 06:48 PM.
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