Puppeteer

Author Topic: New ST5 Questions  (Read 5287 times)

Geno

  • Sr. Member
  • ****
  • Posts: 295
    • View Profile
New ST5 Questions
« on: April 02, 2006, 01:20:14 PM »
This is my first look inside one of these so keep that in mind.
The bearings are the open type so they will be replaced with ones that have a guard on one side and a zerk fitting with relief will be added to the housing on each end. I’ll also check the slip rings and get them trued up if needed. The doghouse will be removed and I’ll get a spare rectifier.

The rotor (and to a lesser extent the stator) look a little rough to my inexperienced eyes. Is it? Does it need any cleaning or finishing? How do I do it? Any suggestions are helpful, I only want to take this thing apart once.

http://www.sprucemtsurplus.com/temp/Rotor.jpg
http://www.sprucemtsurplus.com/temp/Stator1.jpg

Thank You, Geno

Doug

  • Guest
Re: New ST5 Questions
« Reply #1 on: April 03, 2006, 01:13:30 AM »
You get what you pay for when it comes to motors and generators....
Realy this isn't bad at all considering how little these things cost. The surface rust you see on the pole faces is just comestic, but I would If I were you paint the stator and rotor with Glyptal 1201, CRC Clear Urethane seal  coat or some other high quality electrical finish. Look closely at the insualtion class of the machine if its a unit with type F use something that will match it like the Gyptal. Type B Insulation the CRC or low grade product is fine

I can't be sure but If I recall the insulation classes are as follow

B- 120 c
F- 155 c
H- 170c

There are others but you don't see them much Like "C"  "A" and "O". C is higher than H, A and O are lower than B.

Before you paint your winding clean them with a high quality electrical cleaner made for motor windings not "varsol" or "brake clean". Use light coats on the rotor, soak the hell out of the stator. Do this when the parts are cold so paint has some time to penetrate.

Is it the camera or did they use wood to wedge the rotor windings between the pole face and he rotor body. No big deal if it is we used wooden wedges in the motor shops for years....

Don't waste your time with fancy bearings or trying to find ways to grease and purge. Buy 2RS sealed bearings and toss them in the trash when they get noisy. 2Z bearings if you must grease them or it will keep you up at night, but this is a waste of time. 2RS bearings will last you years, no issues for an ST-5 I think you need 6209 2RS for the front and 6207 2RS for the rear. These bearings are HUGE replace them once with a good brand like FAG or SKF and you likely won't need to worry for years.

How to replace bearings pull off th old ones with a puller.....
Ask wife to leave the house, enjoy a day off and buy herself something nice.
Preheat her oven to 250 F
Warm bearings for 10 minuts a pound (joke until hot a little dab of spit will tell you your warm enough)
Slide warm bearings on cold shaft they should slip on like breaze. As extra insurance place rotor in freazer and put a tiny bit of oil in the shaft before sliding bearings

Last and most important: 1. Slide those bearings in all the way don't stop half way and let them cool
                                  2. Never tell your wife you cook bearings in her oven and froze a rotor in the Freezer

Doug


Doug

Geno

  • Sr. Member
  • ****
  • Posts: 295
    • View Profile
Thanks Doug
« Reply #2 on: April 04, 2006, 02:12:51 AM »
Thanks for your help.
Holy smokes, that’s a lot of information in a few sentences but that’s the way I am too. I’ll check the insulation class and get the proper coating and clean it up as well. There are no wood wedges, it was the camera. I have had good luck on fully sealed bearings as well (in other applications) and will use them. I do know the advantage of heating and cooling bearings and their shafts and will do so. My wife has four legs and a tail and will do anything for bowl of food.
http://www.sprucemtsurplus.com/temp/cruise-control.jpg

Thanks, Geno<at>sprucemtsurplus.com
« Last Edit: April 04, 2006, 02:16:29 AM by Geno »

Doug

  • Guest
Re: New ST5 Questions
« Reply #3 on: April 04, 2006, 06:43:46 PM »
No trouble....

Generators are not hard to repair, probably the the most service friendly part of your enture set.

Doug

trigzy

  • Sr. Member
  • ****
  • Posts: 313
    • View Profile
    • High Tech Hicks
Re: New ST5 Questions
« Reply #4 on: April 04, 2006, 09:09:58 PM »
Doug,
       I read your last comment and agreed with it immediately.   Then after thinking about it I've come up with the following comment: "Spoken like a true expert!" 

I've always found electrical stuff real easy to follow, but harder to teach.  For some people the electrical might be the hardest part, it is something you cant see, hear, or smell (hopefully), and touching it is usually quite dangerous....  I know quite a few people that could probably take down & rebuilt the engine 5 times faster than I could, but couldn't wire a circuit breaker up to the generator......  (Of course....  some of them would still try  :-\)

On a side note, I am also reminded of the definition of a "Specialist": Someone who knows more and more about less and less.....


Steve
Power Anand 24/2, Brushless 20kW, some other antique iron.
Vendor of AVR's, Small Clones of Yanmar Diesel and Honda Gasoline Engines

Doug

  • Guest
Re: New ST5 Questions
« Reply #5 on: April 05, 2006, 12:09:44 AM »
We're all "Special"......

Seriously though if anyone here has seent the Canadian TV show "How its Made" they repeat every so often some GE electric motors being rewound and fitted back together. This show tends to take a simplistic view of "how things are made" but if you turn off the sound and just watch you can see some tricks of the trade.
A must read on motor windings and service is also the US navy electric motor service and repair manuals. I found a copy of this from the 1950s at my local public library. Lots of good field service tips not to mention actual tear out and rewind proceedures.
I don't own an ST head but I've looked at the picture and wiring diagrams. These things are perfectly simple in design and clear or purpose. I only wish they came in a Nema (North American) frame size so they could be easier to mount and couple.

And if anyone out there has one with the "k" winding in it I would like to know what the open circut voltage on this winding is at 1800 rpm along with the tap voltage between U5 and U3. There is the potential for a 12 or 24v charging system among other things.....

The one you brought in as a sample is also interesting. Its not an ST but something a little more sophisticated. Just from looking at the pole face I can tell those units will probaly produce less harmonics. If only It was 1800 rpm with an adjustable pilot and brushless main exciter. I'd be all over that like a fat kid on ice cream.....


Doug