37 replies to this topic

[Dan Ebert]

It's nice that the instructions about removing and saving the seal were edited out. It's a shame that a sealed motor was used in this process. It implies cheating. 

The instructions are nice and gives anyone that doesn't understand what blueprinting can accomplish, some knowledge. But using a sealed motor to do this.  

 

Some of the tips go beyond normal blueprinting. Comm tying, timing advancement, and arm shaft replacement would be no-nos with any entry level motor class like you are showing here.

[havlicek]

Honestly, I don't care if everything the guy has written is true or correct in a general sense. I would ALWAYS defer to what guys like Swiss say about the details anyway.  

If the article does nothing more than get people to open up their motors and start screwing around in there, it's a success.
 
-john

[Marty N]

That's a four-jaw independant chuck and he's using with a DTI to center it which is registered from the shaft. He, depending on his skill level, can get that closer than one might think. Closer than most dedicated comm lathes. No matter, it will be an upgrade to a stock Asian comm cut.

What do we think we used for precision work before collet systems? Every precise machine has been made on one less so.

[NSwanberg]

Every precise machine has been made on one less so.

 

Might have been true once but not so sure now with CNC.

[Marty N]

Just asking. How pray tell could it be otherwise?

[Samiam]

The first milling machine was made with a hand file.

[redbackspyder]

Greg, thank you for posting such an interesting article... Some of us appreciate the extensive work that this gentleman put into it...

[Cheater]

Over a period of more than ten years, Mill.

Thanks for recognizing that.

[Guy Spaulding]

Truing the comm by rotating it by the headstock in a big lathe isn't real sound.

For a guy who seems to obsess about detail, there are certainly more precise ways to do it.

Also, does he really think he can change the orientation pattern on standard ceramic mags by using a bowtie slug.

The strands in a ceramic mag are what they are (permanent), be it radial or straight.

I'm sorry, but IMO, this guy is a better draftsman than a motor engineer.

I agree, Mike. That's why I said principles, not techniques. There’s much better ways to skin this cat. 

[Big Booty]

I only saw one thing I would question. When you file the first third off the side of each brush and install the filed side as the trailing edge it doesn't change the timing it only reduces the brush overlap and by doing so it eliminates the underbrush shorts that cause "push starts" and reduces heat.
 
The only way I know to increase the timing using the brushes only is to advance the leading edge of the brush by repositioning the brush hoods. Installing the filed edge of the brush as the leading edge only retards timing and has no affect on overlap.

 
The diagram states "effective timing" is advanced (or retarded). I believe this is correct. A particular pole can not be energized if that segment is being shorted out by the two opposing brushes. No current will flow into the coil. By chamfering the brushes the point at which the coil is energized is "effectively" advanced. This concept only holds true when the brush is so big as to cause overlap and pole shorting.

[nzoomed]

Now I have a question, where can i get new commutators for rebuilds and rewinds?

I cant seem to find anyone stocking them!

[MSwiss]

Shaun,

Posing your question in this thread, to John Havilcek, would give you a better shot at an answer.

 

http://slotblog.net/...-rewind-how-to/

[nzoomed]

Shaun,

Posing your question in this thread, to John Havilcek, would give you a better shot at an answer.

 

http://slotblog.net/...-rewind-how-to/

Thanks for that.

Ive just been reading alot of his threads since ive joined, he is absolutely amazing with his wealth of inspiration.

I see that he builds his own motors that i have seen listed on Ebay earlier, so now i can put two and two together.

It makes me want to go out and rebuild all my old motors ive got in my spares and give them a new lease of life!

Only problem is im really having trouble on where to go for parts, choosing replacement endbells and ball bearings etc, for example i have no idea what brush hoods i need for any particular endbell.

 

If i could get a bunch of parts to go over a few motors it would be great, i will be needing spacers, brushes, hoods springs etc.