You cannot run them on anything. Specifically they will overheat at any frequency much above 25 Hz and will just burn up and not even rotate without load at 60Hz. But they will run very very well on dc. They are essentially the same motors as used in the New Haven's EP-4's, which ran regularly into Grand Central on dc. They will run even better on dc than on 25Hz ac.
You simply did not have the opportunity to try this at Wilmington. But of course at Van Ness in the Bronx it was routine. Try and find a 25Hz commutator motor and try it yourself. But it has to be a commutator motor, no other kind of ac motor will run on dc. And all traction motors on GG1s were commutator motors.
I did, having worked as a lineman and a power director and have family work the loco shop I am well aware what is required. you just seem to think you can run theses motors on anything. they don't and it is way more compicated then you describe.
There may be three AEM7 transformers to support the twelve motors.
I would use the control stand and the 24 or something taps to control electronic relays that would further interface with the standard AEM-7dc control systems. The throttle would look the same, be mechanically the same, but electrically serve a very different function. The transformers would not have multiple taps, except for those already on the AEM7d to switch between 12000 and 25000V power supply and between 60 and 25Hz. If there are simply too many throttle positions on the old GG1 throttle, then two or three adjacent would simpliy be wired together, so that the total number of throttle posiitons would be the same as on an AEM7dc. It is a simple and straightforward solution, and should not be difficult to engineer properly.
erikem Add Quote to your Post You are correct on the motors running well on DC, perhaps the biggest challenge is dealing with the old transformer.
You are correct on the motors running well on DC, perhaps the biggest challenge is dealing with the old transformer.
A potential issue I can see is the degree to which 'prototypical' control systems are to be retained in the "rodded" locomotive (it's not a restoration any more!) The 'old transformer' would be removed intact, if I understand what Mr. Klepper has been saying, and the AEM-7's AC-to-DC equipment substituted; however, the old controller (if I remember correctly) works via a large number of tap changes in the old transformer's structure. So would you move all or most of the AEM-7 controls over to the G? And how would you construct a panel, or desk, or whatever, for them there ... and how would the instrumentation and controls be arranged?
An excellent analysis. But the fact remains that the AC commutator motors will still work better on dc than the do on ac. So there is no problem, other than the rehabilitation costs, of reusing the motors to make the GG1 compatible with a 60Hz electrifcation throiugh rectification and dc operation. So we can keep the same motors. This is an appropriate solution for a single locomotive restoration for historical operating purposes, but probably not if they had wished to rebuild the fleet.
Turns out that I was wrong about GN only using M-G locomotives on the single phase edition of the Cascade tunnel electrification. For about one yea starting in 1929, the GN had a couple of Spokane & Inland Empire locomotives modified to run on 11kV versus the 6.6kV on the S&IE.
Some commets about motors...
AC commutator motors do work, but they almost always heavier, more expensive and less efficient than a DC series motor. AC commutator motors don't scale up in size as well as DC motors, hence the dual motor per axle mount on the GG-1, but first used on the New Haven (and later used on the 3kV DC Westinghouse passenger lcomotives for the Milwaukee). One other problem was that it was difficult to get regenerative or dynamic braking working with AC commutator motors.
Three phase AC induction motors were considered from early on as being closest to the ideal traction motor, being simple, rugged and providing inherently high adhesion from the smooth torque and steep torque curve (a little bit of wheel slip would cause a rapid dropoff in applied torque. Two downfalls from the early years was the more or less fixed operating speeds and the requirement for two overhead conductors prior to the development of the phase converter. The fixed operating speed limitation has been overcome with variable frequency inverters.
The motor genearator design was a way of getting variable speed regeneration with an AC electrification.
- Erik
You're quite welcome.
I've had my share of memory confusion as well. One example ws thinking the UP's 8500HP GTEL's used something besides the 752 traction motors, found out recently that I had confused the Big Blows with the FM Erie-builts...
Thanks.... Believe my memory confused the GN and N&W speeds
daveklepper The original Cascade Electrification... But the original electrication did use synchronous induction motors, and were not capable for speeds beyond about 25mph. Correction, two operating speeds, 14 and 28 mph. How they got to those speeds or transitioned between is something I would like to relearn!
The original Cascade Electrification... But the original electrication did use synchronous induction motors, and were not capable for speeds beyond about 25mph. Correction, two operating speeds, 14 and 28 mph. How they got to those speeds or transitioned between is something I would like to relearn!
Dave,
The GE made GN three phase locomotives used wound rotor induction motors and the original single operating speed was 15.7 MPH. Wound rotor motors used slip rings to connect to a variable starting resistance, with maximum resistance at zero speed and reduced as the speed increased until it was shorted out at operating speed (which was slightly below synchronous speed). The output of the slip rings was three phase AC at a frequency that was the supply frequency minus the percentage of slip times the supply frequency. With 25Hz and at half synchronous speed, the output frequency would be 12.5Hz (which would be about 7.8 mph on the GN locomotives). Someone got the bright idea of using that to supply another motor and provide a half speed connection (called a "cascade" connection because the motors are operating in cascade).
Westinghouse Electric one-upped GE on three phase locomtive design by developing the phase converter which allowed three phase locomotives to operate off of single phase. Having a single overhead conductor greatly simplified overhead constuction and allowed a higher operating voltage. The N&W locomotives were set up for 14 and 28 mph running speeds and used a liquid rheostat for the variable starting resistance and used cascade connections to change speed.
The VGN statred out with phase converters on their original locomotives, went to motor generators for the first post WW2 order of locomotives and ignitron rectifiers for their last order of electric locomotives.
P.S. A few years ago, GE dusted off the lessons learned with the cascade connection of wound rotor induction motors and made an adjustable phase transformer for asynchronous connection of power grids - the transformer can be rotated to overcome the small frequency difference between two grids. There are two advantages over a DC intertie - one is that it should be a bit more efficient, the other is that it will pass reactive power as well as real power.
Thanks for the correction.
Modifications by PRR must have included the PRR cab-signal ATC system.
All of the 11kV single phase locomotives GN owned were motor-generator equipped, though GN had some AC commutator locomotives on the Spokane and Inland Empire.
According to Middleton, the GN Y-1 locos (the ones resold to PRR) were motor-generator sets, and the traction motors were in fact DC. He mentions they were modified at Altoona, but does not go into detail.
No intention of replacing the motors. Again, 25Hzac commutator motors have zero trouble operating on ac, and GG1s have commutator motors, not induction, not hysterisis synchronous. Three AEM7 electronics, electricals, and transformers are needed to power all twelve motors, but the motors can stay. These GG1s operated well wethout major problems before they went on exhibition, and they traveled to their location on their own wheels. You are overstating problem, but your estimate of cost may possibly be on target. I agree a thorough rebuilding woiuld be required. This would include dissasembling and checkiing each motor for insulation, re-insulating the pantographs for higher-voltage protection, etc. Read the whole thread to get an idea of the purpose and the work involved.
1) the motors on a AEM7 are physically larger then the westy/ge 625A motors that are paired in 1 housing. therefore they won't fit in the frames. 2) control circuits would have to be completly replaced, a very expensive operation. #3) the frames themselves would most likely fail a FRA inspection due to cracks and old welds. who you gonna get to cast new ones??? the more you keep it set up for 25~ and 11kv the less headaches. this was tried yrs ago and the costs just to make it operate as a "cab control car" was over 275K from wilminton. the frames and fixtures and tools have all been scrapped. and left over parts have been cut up or scrapped. I belive it wpuld take at least 5 million to bring any G back to operational and Appearance condition as built.
38 yrs with Amtrak, 2 brothers and father with combined over 120 yrs RR expeariance at the Wilmington Loco Shops
The original Cascade Electrification was a three-phase, two-overhead-wire electrification, like the Toreno - Sondrio electrification (rode it) and others in Italy. In Italy, most were replaced with 3000V direct current. The original GN electrification was really just for the Tunnel itself. When the electrication was extended the New Haven's electrfication and the original PRR suburban electrification were already practical demonstrations, and 25Hz ac at 11000volts was adopted. Several GN locomotives did pusher duty for the PRR after the end of GN's electriciation. They also used commutator motors that operate on the same principles as dc motors and can run on dc. But the original electrication did use synchronous induction motors, and were not capable for speeds beyond about 25mph. Correction, two operating speeds, 14 and 28 mph. How they got to those speeds or transitioned between is something I would like to relearn!
Yes he did. As the Italian railroads were state-run Il Duce was in a position to kick butt and make it happen.
Not that this excuses everything else he did.
CSSHEGEWISCH Were induction motors used in the original Cascade Tunnel electrification and in northern Italy prior to WW2?
Were induction motors used in the original Cascade Tunnel electrification and in northern Italy prior to WW2?
Benito Mussolini promised to make the trains run on time; I do not know if he succeeded or not.
Johnny
The ac-commutator motors used on the PRR, NYNH&H, GN, Virginian are essentially dc motors with accessory coils that mitigate bad effects of the pollarity changing 50 times a second for 25 Hz ac. Their principle of operaton is the same as a dc motor. They have field coils, commutators, and armetures similar to dc motors. They are now considered obsolete as ac motors. And they actually work more efficiently on dc. The New Haven had absolutely no need for inverters to run its ac-commutator motors into Grand Central on the Central's dc third rail, just a different and parallel control system.
Modern ac motors have a different operating principle. Instead of armeture coils and commutators, they have rotating conductors, copper or aluminum, somewhat slanted. The field coils around receive ac power with the frequency dependent on speed. The rotating magnetic field produced by the phased electronig switching of the field coils creates current in the rotating bars, which in turn sets up its own magnetic field that tries to lock in and follow the magnetic field(s). They are often called induction motors, but the full description is "hysteresis non-synchrounous" motors. Installing such motors in a GG-1 would be frightfully expensive. And there is no practical way the existing motors could be modified to become such motors. These modern ac motors are just as useful for dc-powered lines as well as for ac-power either from catenary or diesel-powered alternator generators. The ac power is first rectified to dc, then inverted under computer control with frequncy with speed of rotation dependent on load and speed.
And note that the first diesel-electrics that used alternators instead of dc generators used dc motors.
True induction motors have bars that are not slanted but all parallel to the axis of rotation, and they operate efficiently only at the exact speed of the rotating electric field of the armature coils. Your computer's fan-motor is probably a good example.
I never knew that an AC motor could run on DC. Would efficency suffer? (maybe not a problem to a restored loco) If Amtrak had rebuilt the GG1s, would they have used an inverter?
But if a reader of this post can open up a bank account for the restoration of GG1 to operation, possibly within an existing railfan organization, and makes a reasonable contribution, I can promise a $100 contribuion by the end of February and at least that every year following.
ןI HAPPEN TO BE LIVING ON SOCIAL SECURITY, WHICH IS POSSIBLE IN JERUSALEM IF NOT IN NEW YORK CITY, SO CONTRIBUTIOND MUST BE MODEST. IF CONDITIONS IMPROVE, SUCH AS ROYALTIES ON BOOKS OR PATENTS, OBVIOUSLY I WILL DO BETTER. THIS PAST YEAR I CONTRIBIUTED TO ELEVATING THE COLLECTION AND THE NORFOLK AND WESTERN J CAMPAIGNS. ELEVATING THE COLLECTION RAISED OVER TWO MILLION, AND YOU CAN SEE THE PROGRESS AT WWW.BERA.ORG. I HOPE TO CONTRIBUTE TO THE K4 CAMPAIGN IN THE FUTURE. PARDON THE TEMPORARY GLITCH ON MY COMPUTER THAT FORCES USE OF CAPS ONLY. USE LOWER CASE FOR THE INTERNET ADDRESS.
The success of the Shore Line Trolley Musuem in raising money to "elevated the coillection" and undo the damage Sandy caused indicates that money is available for very worthwhile railfan causes, if goals and timing are realistic, and people managing the project are known to be capable. I am sure the Pennsylvania RR Musuem does already have a core of volunteers who contribute time and money. They will require financial help in large measure to implement the program here suggested, but their approval and cooperation is essential befor the program gets off the ground. Approval from the Musuem, from Strassburg RR, and from Amtrak is also essential. The money should be raised for an ongoing program to the end that all equipmenet at the musuem that can be made operational should be made so, not just the 4935, but certainly the D16 and E6. The choice of which locomotive should be the first in the program should result from a concensus and is not necessarily the GG1.
But if it is the GG1:
First step is a qualified engineer to estimate the costs, determine whether or not Amtrak wilmington can do the job if schedule at time when the shop isn't near capacity, and with all expenses paid by the restoration fund. If it cannot be done at Wilmington, anothe location must be found.
The goal is a locotive with the capabilities it had when new, even though its ussage will generally be with lighter consists, and the capability of running anywhere on the NEC, now and after the NEC upgrading. Basically, it will be converted into a rectifier,-dc-motor locomotive, which logically is what would have been done if Amtrak or NJT had decided to modernize and retain this type of power. Externally it will be unchanged, and even the two cabs will look close to original.
Both "Rivets", 4800, and 4935 will be taken to Wilmington and all parts evaluated. The motors, pantographs, quill drives, couplers, draft gear, truck frames, etc., that are in the best condition will go to 4935 with the understanding that 4800 will remain a static exhibit.
Pantographs, reconditioned, re-insulated with modern material for 25000-volt operation.
Line switches, contactors, circuit breakers, transformers, rectifiers, from three retired AEM7's where possible, otherwise new. Electrically, the restored GG1 is three AEM7dc's.
Controls. Some custom work required to mate AEM-7 controls to the physical operating handles of GG1 controls. Considerable engineering required to make this possible.
Quill drives, twelve motors, all existing GG!. The GG1 motors will function well on dc, running a bit cooler than they did on 25HZ ac.
Fans and blowers, existing GG1 where possible, otherwise from AEM7dc's and/or new.
Lights, interior and exterior, cab ventilation and heating, crew seats, air filters, wiring, the best new material available to fit the physical existing situation of the 4935.
The understanding is that the restored 4935 will normally be displayed at the museum. An allotment of time for operation will be agreed-upon in advance. The consists hauled will normally be limited to insure minimum wear and a long restored life. Once or twice a year a fan-trip for enthusiasts, and once or twice a year for ceremonial roles for Amtrak or commuter authority projects in and connected to the NEC are what I would envision. Done right, the 4935 should be available for such purposes for a half-a-century or more.
And the fund-raising should continue for the other power at the museum.
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