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Old Nov 09, 2012, 09:40 PM
Aka: Tom Jenkins
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Palm Beach County, Fl.
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Ok! So I got a pound of 18ga and a pound of 20ga wire, insulator tubing and paper
Question is, how do you correctly drill out the pin on the stator holder of a Scorpion motor?
Its like being all dressed up and no place to go!
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Old Nov 10, 2012, 07:30 AM
Jack
USA, ME, Ellsworth
Joined May 2008
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On this kit motor build on the Scorpion pages they discuss the options for adding either a screw or a piece of wire to act as a pin to keep the stator from rotating on the bearing tube.

http://www.scorpionsystem.com/buildi...ld_and_review/

If you have the pin, and the stator is glued to the bearing tube, heat will normally soften the glue and allow you to slide the stator off.

I have done that on some smaller motors. When the stator do no have the pin to keep them from pin to keep them from rotating I directed the heat from a micro torch into the bearing tube and used a gloved hand to try to rotate the stator a little. As soon as it would move I was able to slide it off.

On another I was able to use a flat screwdriver as a lever between the end of the stator and the base plate and apply some gentle pressure that was trying to lift the stator on the tube. When the inside of the tube go hot enough, it moved. If you tried too hard too soon in the heating process, it put the stator and and other parts at some risk of damage.

it all requires some inventiveness, cunning, gloved hands, and maybe even some luck...

Others have heated the stator from the outside in, some putting it on top of a stove burner for example, and that worked. That method can put the stator coating at risk of being burned off, I was trying to avoid damaging the coating on the motors I did.

Jack
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Old Nov 10, 2012, 07:47 AM
Aka: Tom Jenkins
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The stators in the motors I have are raw plates, the ends are gfk(g-10)
How hot can I go without damaging the iron?
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Old Nov 10, 2012, 08:16 AM
Jack
USA, ME, Ellsworth
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So those have all been rewound in the past and brought to higher levels of power. G-10 will handle some heat, the spec here says it is OK with 285F (141C) constant:

http://www.jjorly.com/g10_fr4_techni...tions_data.htm

When you put the heat inside the bearing tube, the heat acts pretty quickly on the thin adhesive layer that is between the tube and the stator. So the stator itself does not get very hot very quickly.

I had a strip of metal (made from a construction brace I had on hand) and I drilled holes to mount the motor do that so that I could direct the flame from the butane micro torch into the bearing tube from either end.

I clamped the metal strip vertically in a vise, played the flame into the tube from each end for 10-15 seconds at a time, and used a gloved hand to test the stator adhesive for being soft. And it did not take long to get the stator off.

I have read that 150-200C or so is enough to soften epoxy, if the G-10 will handle 141C constant I think it is practical to hope that you can get a release on the adhesive before the G-10 is damaged. Maybe. I hope.

Jack
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Old Nov 10, 2012, 12:38 PM
Aka: Tom Jenkins
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What I'm doing presently Jack is heating in the counter top, meanwhile inserted some washers against the windings and have long screws tightened, we'll see. I did find some CRC freeze spray hoping to shrink the center after heating thoroughly to bake the epoxy.

PS: the visit to Electric motor repair of West Palm Beach was the high lite of the year for me. The fellow had an airbag table with a 500 lb 3phase he was rewinding. The wire is on 200lb spools that feed to a coil winder with a foot/lap counter while the oval spindle is two part adjustable for custom phase coils in the BIG motors! The largest they carry is 10ga-2.59mm for your next 5055 you rewind!

Tom
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Last edited by ApexAero; Nov 10, 2012 at 12:49 PM. Reason: PS:
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Old Nov 10, 2012, 03:29 PM
Jack
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Pushing the stator off with screws might work good on the Scorpions, especially of they have the hardened steel thread inserts in the holes for the mounting screws.

Jack
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Old Nov 11, 2012, 01:12 AM
Aka: Tom Jenkins
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Nope, no helicoils. The holes should probably be tapped to 4mm after the treatment I gave them! I finally got it apart last eve by 6 pm. It took 350 degrees for an hour an a half with constant tightening the screws. I had a stack of nickles to bush the screw ends against the windings, kept inserting another until the stator popped off the holder. The pin was no prob after heating, I was hoping to unwind the thing but will probably have to cut the wire and pull it off the stator, the epoxy coating has got it stuck well.
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Old Nov 11, 2012, 09:18 AM
Jack
USA, ME, Ellsworth
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I think the micro torch and heating the tube from the inside out might be quicker and better. Maybe you can give that a try on one of the others...

Here are some ideas on removing the epoxy saturated windings. The last thing I would ever do to a motor it saturate the windings with epoxy unless the need to do that was obvious and imperative. I am not going to do it until I have had a least one tragedy take place that epoxy would have prevented...

http://www.rcgroups.com/forums/showt...5#post18210569

Jack
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Old Nov 11, 2012, 11:15 PM
Aka: Tom Jenkins
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Well after investing about 6hrs yesterday and today I finally got it stripped and prepped. I used .007 G-10 on the end plates glued with CA.
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Old Nov 12, 2012, 08:16 AM
Jack
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Looking good, what is the material you are lining the slots with?

Jack
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Old Nov 12, 2012, 07:30 PM
Aka: Tom Jenkins
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The fellow at the electric shop has sheets 24"x36" of insulator paper that has a peel off, the material is sticky and doesn't slide around but will glue in the slot when the time comes.
I'm looking for a set of duck bill pliers(flat and square) to modify for squeezing the wire etc. Any idea where to look? Harbour Frieght only has them in a small electrical set.
If you need some of that insulator material lemmie know and I'll cut it to envelope size for you.
It is old and free!
Next question is, I can do an LRK wind doing 6 wraps per tooth to get into the 1k area, if I go another wrap to make it 7 is that like a (sorta) half turn? to lower the Kv a fuzz more.
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Old Nov 12, 2012, 07:51 PM
Jack
USA, ME, Ellsworth
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Thanks for the offer on the paper, I'll keep it in mind should a need arise.

On the pliers, I remember seeing a thread (croco? ditto? helifreak?) with photos of a pair of much modified Knipex pliers that were purported to be the essential tool for those rewinds. I think I remember them a being a type of parallel jaw pliers of maybe something like that. Do you see them here?

http://chadstoolbox.com/knipex.aspx

A google for Knipex pliers (or even an eBay search) will probably turn them up.

Good luck with the quest on those...

As a tool queer with a life-long commitment to collecting tools I can sympathize...

Found the thread! It is here and you may need to be logged in to see the images. Let me know if you want them and I'll post them here.

http://www.helifreak.com/showthread....ex#post3668876

Jack
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Old Nov 12, 2012, 08:53 PM
Aka: Tom Jenkins
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Yes I've seen them also, I'd seen a video of a guy winding a motor using the flat pliers and the angle looks better for my hands, 25 yrs of heavy construction wasn't kind. I'll look into the Knipex.
Tom
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Old Nov 12, 2012, 09:29 PM
Jack
USA, ME, Ellsworth
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And they are using the pliers to make the turns on the corners? Is that it? I understand the business of the jaws having to be polished but not quite how they are used.

There are a *lot* of pliers on eBay...

Jack
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Old Nov 13, 2012, 05:39 PM
Aka: Tom Jenkins
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What do you think of these, looks simple to modify.
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