Jump to content




Photo

Accidents will happen...


  • Please log in to reply
9 replies to this topic

#1 SlowBeas

SlowBeas

    Troublesome De-slotter

  • Subscriber
  • PipPipPipPipPip
  • 782 posts
  • Joined: 15-January 07
  • Gender:Male
  • Location:Lost in South Carolina, USA

Posted 10 November 2017 - 11:35 AM

... that make me realize how little I really know about assembling a good motor. Here's my plight:

 

Several years ago, I bought a Mura Challenger motor. I never really used it for anything, but recently pulled it out of my motor stash to see if it would run. Put it on the power supply... not bad, but the amp draw seemed to fluctuate under constant 5v. So, I thought I'd open it up and see if there's something binding inside that would cause it. That's when it happened.

 

As I opened the can, the arm fell out–- as did the magnets. Uh-oh.

 

How do I know that I've put the magnets back in their appropriate space and turned the correct way inside the can? I seem to recall that it matters which end faces the endbell. I don't see any identifying marks.

 

See what I mean? I know very little. Your insights would be appreciated.

 

jb


Jim Beasley
South Carolina, USA

"Assuming either the Left Wing or the Right Wing gained control of the country, it would probably fly around in circles."
- Pat Paulsen, 1968
"I drive way too fast to worry about cholesterol."
- Steven Wright ca. 1983




#2 Pablo

Pablo

    Builder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 12,577 posts
  • Joined: 20-February 06
  • Gender:Male
  • Location:Johnson Bayou

Posted 10 November 2017 - 12:12 PM

Which ends face the endbell matters not.

 

Left to right, you have two choices:

 

1. It doesn't matter, just switch the lead wires if necessary to make it run according to the timing.

2. If the motor runs reverse of the arm timing when you have the wires the way you want them, switch sides on the magnets.

 

If I had knowledge of those motors, I could tell you which side the north and south mags go on, but I don't.


Paul Wolcott

#3 Mbloes

Mbloes

    On The Lead Lap

  • Subscriber
  • PipPipPipPip
  • 478 posts
  • Joined: 19-April 12
  • Gender:Male
  • Location:Los Angeles, CA

Posted 10 November 2017 - 12:42 PM

If the magnets are painted, typically the "white" magnet is the rear magnet in an anglewinder configuration.

 

Otherwise, get another one of your motors that rotates correctly. Take one of the Challenger magnets and place it on the outside of one of the magnets of the assembled motor. If it sticks, that magnet goes in the same place – if it repels, it goes on the other side of the motor.

 

Does this make sense, Jim? I would post a pic but I'm at work (where I do all of my posting).


  • Cheater likes this
Mike Bloes

#4 olescratch

olescratch

    olescratch

  • Subscriber
  • PipPipPipPipPip
  • 548 posts
  • Joined: 19-July 13
  • Gender:Male
  • Location:Ravenna, OH

Posted 10 November 2017 - 04:59 PM

If the magnets are painted, typically the "white" magnet is the rear magnet in an anglewinder configuration.

 

Otherwise, get another one of your motors that rotates correctly. Take one of the Challenger magnets and place it on the outside of one of the magnets of the assembled motor. If it sticks, that magnet goes in the same place – if it repels, it goes on the other side of the motor.

 

Does this make sense, Jim? I would post a pic but I'm at work (where I do all of my posting).

I was taught in school, many, many, many years ago, that opposites attract and that similar polarities will repel.  Given that these magnets follow this 'rule' your suggestion may be in reverse!


John Stewart

#5 Mbloes

Mbloes

    On The Lead Lap

  • Subscriber
  • PipPipPipPip
  • 478 posts
  • Joined: 19-April 12
  • Gender:Male
  • Location:Los Angeles, CA

Posted 10 November 2017 - 05:16 PM

Yeah, I wasn't clear.  Similar polarity magnets will "stack" - that is, the inside of one magnet will stick to the outside of another with same polarity.

 

Place your loose magnet's inside surface on the outside magnet surface of your correctly oriented motor.  If the inside surface sticks, install it in the same place in the unassembled motor.

 

If the inside of the magnet repels the outer surface of the motor's magnet, it goes on the other side.

 

Update:  Maybe this pic explains it better:

 

magnet.jpg

 

Just visualize these in a motor.


  • olescratch likes this
Mike Bloes

#6 MSwiss

MSwiss

    Grand Champion Poster

  • Advertiser
  • PipPipPipPipPipPipPipPip
  • 18,268 posts
  • Joined: 16-April 06
  • Gender:Male

Posted 10 November 2017 - 05:25 PM

I was taught in school, many, many, many years ago, that opposites attract and that similar polarities will repel.  Given that these magnets follow this 'rule' your suggestion may be in reverse!

John,
You are right, opposites attract, but Mike was right, too.
 
The below pic shows clearly, what he was trying to convey.
 
The magnet outside the can is the same polarity as the magnet it is attracted to,inside the can, because the front of the magnet is sticking to the back of the magnet in the motor.

20171110_161740-1.jpg


  • olescratch likes this

Mike Swiss
 
IRRA® Components Committee Chairman
Five-time USRA National Champion (two G7, one G27, two G7 Senior)
Two-time G7 World Champion (1988, 1990)
Eight-time G7 King track single lap world record holder
17B West Ogden AveWestmont, IL 60559, ( 708) 203-8003
mikeswiss86@hotmail.com (also my PayPal address) 
Note: Send all USPS packages and mail to: 5858 Chase Ave., Downers Grove, IL 60516
Make checks out to Chicagoland Woodworking, Inc.


#7 olescratch

olescratch

    olescratch

  • Subscriber
  • PipPipPipPipPip
  • 548 posts
  • Joined: 19-July 13
  • Gender:Male
  • Location:Ravenna, OH

Posted 11 November 2017 - 06:40 PM

Once again, a pic. is worth a thousand words!  Thanks for the explanation/pics to relay this info.


John Stewart

#8 SlowBeas

SlowBeas

    Troublesome De-slotter

  • Subscriber
  • PipPipPipPipPip
  • 782 posts
  • Joined: 15-January 07
  • Gender:Male
  • Location:Lost in South Carolina, USA

Posted 13 November 2017 - 12:27 PM

Very good insights. Thanks to all. I'll give it a try to see if I can reassemble this thing correctly this time. First time I hooked it up to a power supply, I thought I was going to bring down the house --- sparking and rumbling. I could tell that the brushes were making terrible contact with the comm and the stacks were rubbing the magnets.

 

This time, I'll take a little more care in assembly.


Jim Beasley
South Carolina, USA

"Assuming either the Left Wing or the Right Wing gained control of the country, it would probably fly around in circles."
- Pat Paulsen, 1968
"I drive way too fast to worry about cholesterol."
- Steven Wright ca. 1983

#9 Mbloes

Mbloes

    On The Lead Lap

  • Subscriber
  • PipPipPipPip
  • 478 posts
  • Joined: 19-April 12
  • Gender:Male
  • Location:Los Angeles, CA

Posted 13 November 2017 - 01:05 PM

Jim, if the magnets just "fell out", do you have magnet clips installed to hold them in place?  If things are rubbing, it doesn't sound like it.


Mike Bloes

#10 SlowBeas

SlowBeas

    Troublesome De-slotter

  • Subscriber
  • PipPipPipPipPip
  • 782 posts
  • Joined: 15-January 07
  • Gender:Male
  • Location:Lost in South Carolina, USA

Posted 14 November 2017 - 11:41 AM

They were clipped -- but I obviously did a poor job of it. The end of one magnet seemed to stick out slightly and rub as the arm rotated. Will certainly do a better job rebuilding after applying the above recommendations.


Jim Beasley
South Carolina, USA

"Assuming either the Left Wing or the Right Wing gained control of the country, it would probably fly around in circles."
- Pat Paulsen, 1968
"I drive way too fast to worry about cholesterol."
- Steven Wright ca. 1983





Electric Dreams Online Shop