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Page 1 of 7 Single-Phase Power for Motor-Generator 10Ees 10/10/2017 Single-phase Power for Motor-Generator 10EEs Page 1 of 7 Thread: Single-phase Power for Motor-Generator 10EEs Thread Tools Search Thread Display 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. Attached Thumbnails Last edited by peterh5322; 03-03-2008 at 12:20 PM. http://www.practicalmachinist.com/vb/monarch-lathes/single-p... 10/10/2017 Single-phase Power for Motor-Generator 10EEs Page 2 of 7 Reply With Quote 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!!! Reply With Quote 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. Reply With Quote 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 Reply With Quote 03-09-2008, 11:11 PM #5 Join Date: Dec 2002 Location: Monterey Bay, Diamond California Posts: 10,260 Post Thanks / Like Likes (Given): 27 http://www.practicalmachinist.com/vb/monarch-lathes/single-p... 10/10/2017 Single-phase Power for Motor-Generator 10EEs Page 3 of 7 Likes (Received): 191 "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. Reply With Quote 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 Reply With Quote 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. Reply With Quote 03-13-2008, 02:05 PM #8 Join Date: Dec 2002 Location: Monterey Bay, Diamond California Posts: 10,260 Post Thanks / Like Likes (Given): 27 http://www.practicalmachinist.com/vb/monarch-lathes/single-p... 10/10/2017 Single-phase Power for Motor-Generator 10EEs Page 4 of 7 Likes (Received): 191 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.
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