Hi everyone,
I am having difficulties with the restoration of a Pyle National K2 turbo generator. The unit is very interesting as it has an international broker plate attached beneath the original Pyle National plate, which itself features the older version of the company logo. At the time being, I am trying to remove the turbine cover.
As I understand it, to remove the cover, the bearing must come off the end of the shaft, in order to remove the casting. At the current time being, I cannot get the ball bearing nut to come off. I am to the point that I will be making a special tool that has a ridge to lock into the notch in the end of the shaft in the generator housing, so I can apply force to the shaft to undo the nut. I have already tried applying force and grabbing the shaft collars in between the two unit housings, but the collars are not tight on the shaft and it just began to spin.

The second question I have is would it be a problem if I removed the rotor assembly? I have been told that with the British Stone generators and various versions of German generators, this is an absolute no as it will corrupt the magnetic field of the unit. On the K2, the unit is very loose on the shaft and seems as if it is meant to be easily removable for maintenance and replacement. Would that be an issue?

No, the bearing does not have to come off the end of the shaft by removing the nut. There's a spring loaded device that sort of snaps the sleeve on the bearing assembly onto a keyway in the main shaft. If it's been there a very long time, try a lot of penetrating oil followed by prying from opposite sides (180 degrees apart) of the cover simultaneously against the main body.

Once the splined drive washer is off the armature end, just pull the damn thing off and don't worry about phantom magnetic fields. These are pretty robust and idiot resistant, patch in the field machines.

The expert is Bernie Watts of Backshop Enterprises. I would encourage you to maintain a line of contact with him for questions and for parts. He can build a new one or replace any part of yours.

dave

Dave beat me to it. When in doubt, ask Bernie Watts. He's the go to guy on air pumps, generators and many other things. Good guy!

What both of these guys said, and a very positive recommendation for Bernie Watts. One of the reasons for the the bearing to be mounted in this manner with the spring clip on the sleeve, is that one has to remove the end housing in order to adjust the governor screws which pass through the turbine wheel and have square heads. Normally to remove the end cover there is no need to remove the bearing oil res. cap. One just pulls the hole end plate bearing, oil and all off keeping it level when setting it aside, when you are making governor adjustments. One may have to make this off/on procedure several times to get the speed/volts right. You may find as I did on one a couple years back that the governor mechanism is badly worn. Bernie has all of the parts and at what I thought was a reasonable price.

"Corrupting the magnetic field" can be a real problem. It can even occur in the situation where a DC generator hasn't been used for a while, as described in this link: https://answers.yahoo.com/question/index?qid=20080114195451AAeFIer. The link describes how to overcome the problem for a DC generator which has field coils, such as the K2, using a technique called "flashing".

This technique would not apply to DC generators which have permanent magnets - I suspect this might be the source of the warning you have received.

I used this "flashing" technique on a Pyle-National (E or E2, I think) generator three or four years ago when working on the turbo-generator for SLSF 1630 at the Illinois Rwy. Museum. During the 1492-day service work, the generator was found to have a "bad" field coil. After swapping in a good field coil, a bench test of the the generator did not generate any voltage when running on 90 PSI air with no electrical load.

I did some web searching which resulted in the link shown above. I suspected that there was no residual magnetism in the "new" field coil, so I disconnected the field coil wires, momentarily "flashed" the field coil using a 12V automotive-type battery, then re-connected the field core wires. After this procedure, the generator produced something like 20 Volts when run on 90 PSI air with no electrical load.

That generator was put back on the locomotive and has been in-service since it's return to service for the 2014 operating season.

You can always turn to a motor rebuild shop for professional help if you have difficulty with the electrical/magnetic portions of the generator...

As to disassembly, this thread may have some useful information for you: http://www.rypn.org/forums/viewtopic.php?f=1&t=1353.

Regards,
Bob Milhaupt
Occasional Steam Department Volunteer
Illinois Railway Museum

The "residual magnetism" is only applicable to "self-excited" generators, meaning that the generator is powering its own field. Occasionally a diesel that has been sitting for a long time will have a problem with the aux gen loosing magnetism (or a new aux gen), in which case, Bob's solution is simply applied with a heavier source of electricity.

If you have a generator that uses an external source of the field current (such as a diesel's main gen, drawing field current from the batteries and aux gen), or permanent magnets, Bob's solution won't work, though you won't run into that problem with external source of field current.

On a permanent magnet generator, if you lose magnetic field due to age, you have to replace the magnets.

There should be no need to disassemble the generator (dynamo or whatever the word of the week wants to be). A brief application of a 9v battery to the output leads in the polarity that you want the output to be should do the trick. If you flash the generator with reverse polarity it's output will be reversed. On a steam loco with nothing but incandescent lamps you may never notice but if you happen to have a radio or other electronics they probably won't have a deep appreciation for the reverse polarity.

If you have a gen producing reversed power, you should be able to correct it. I'd use a 12v automotive type battery through a fuse and flash it in the correct direction, NOT while it is running.

Always use caution, 32 volts may not seem like much but can give you a serious jolt especially if you are sweaty, and is more then enough do start and sustain an arc, this voltage is similar to what a mig or stick welder uses.

There are parts in the governor that are prone to wear, if not consumable in the case of the thrust bearing. The little bakelite insulating washers and sleeves don't last forever either. So, I would encourage disassembly provided the condition is not known before going into service. The commutators need periodic meggaring cleaning, undercutting, turning, dipping and baking, and the fields also need attention as their insulation gradually deteriorates. Brushes and brush springs in particular have a hard life......

Go through it if you don't already know what you have. Replace worn parts with good parts. Have the quality of the coils checked out by professionals. Avoid something else that can ruin your day.

dave

I sent you an email, but it case you didn't see it -

So after having gone through many of the parts and being fully under way with the restoration, I've determined that the shaft of the unit is bent at the turbine wheel. The shaft swings around 3 thousandths of an inch when held between centers (markings are hundredths of a millimeter). In the photos the shaft is bending away from the camera. Is this within the acceptable tolerances for the unit? It was known that one of the two units we have had a bent shaft, it just wasn't known which one till now. When I slowly test ran the unit with the shaft still in the bearings, I got a much smaller reading of swing on the generator end.
Hoping to find an answer here before contacting Bernie Watts

Also Dick I did not see your email but I am definitely interested in this operating manual you have!

Also for everyone out there, this unit is not needed at the time being. I am slowly going through parts we have in the storage wagons and restoring them in my spare time (extra days in the shop). The condition of both units is unknown (now a little less so), so I intended to go through the entire unit to see what I had and figure out any repairs necessary.

Thanks in advance everyone!

Check the runout at the armature - I don't think .003 is going to be an issue at the turbine wheel, but if it throws the armature off, the brushes will bounce rather than seat, with unfortunate results. Of course, if you know where the high spot is, you could simply gently tweak it back into straight.

dave

Send me your email address.

N&W Historical Society (https://www.nwhs.org/archivesdb/) has drawings for the a K-2 shaft (NW-C331500), case packing (NW-C33121), and turbine cover packing (NW-B33148). I have copies, but their prices are reasonable and their service is quick so please contact them for copies.

On the shaft drawing it looks like the area on the right that you marked has a plus or minus .0005" tolerance. The one on the left is plus .0000", minus .0005".

I rebuilt one for SVRy a couple seasons ago. I made a short shaft to pass through the armature to mount it for turning the commutator. When I reassembled it to the dynamo shaft I checked run out, it had a bit more than I was comfortable with, so rechecked the armature by mounting in the lathe again, also having rechecked my temp. shaft. All was well there, and the dynamo shaft seemed pretty good as well, but not so good with the armature mounted. After a little fussing around, I reinstalled the armature 180 deg. around and wallah, all was better and quite acceptable, probably proving the original mfg. tolerances were not that tight.

Has anyone come to the point where the frictionless element needed replacement? I am tempted to clean out all of the carbon remains and epoxy glue a Teflon disk into its place. I figure that way I can keep the original unit with the governor regulator and slightly modernize the unit.

Might possibly create two Teflon screws to mount the pad to the unit and let them be worn away.....?

Also for the sake of history, does anyone know when Pyle changed the identification tag from the large and elaborate square to the small rectangular tag? I had the other unit out today to start evaluating the work needed on it. It looks to be like a serious basket case around some areas.......