16 replies to this topic

[Zapf]

Hello,
 
I am new to this board. I am looking for some information on the K&B Challenger motors. 
 
I recognize that there are two main types – the Challenger, and Super Challenger. I do have Challenger motors in either black or white frames, but internally they look identical.

I really like the simplicity of these motors. They are easy to disassemble for such maintenance as polishing the commutator.  Over the years I have picked up a number of the Challenger Motors. It is rare that one won’t run with minimal maintenance, except if the magnets have lost all of their magnetism (heat?) or there is some mechanical issue with the armature.  

All of my K&B cars (1/24) have the Challenger motor. I have swapped out Super Challenger motors from cars that have had that motor. Mostly I want the cars to be even competitors with each other.

On my small track that motor works perfectly. The Super Challenger motors, however, do not like that track. The small track is powered with 14.8 volt wall warts which I believe are rated around 1 amp. The Super Challengers run much slower than the Challengers on the small track.

On my larger track with a higher amp regulated power supply (but still  usually set at 12 volts) the Super Challenger motor is OK. No great shakes, but OK.

I believe the Super Challenger is rated at 6v, while the Challenger is rated at 12v. I could be wrong. My first question is, why are the Super Challenger motors slower than the Challenger motors at a given voltage? I would think they should be faster.  Actually I would appreciate any information about the differences between these motors especially in terms of electrical needs/performance.

Secondly, while I have a couple spare brushes, I have not found a source for them. Any ideas for a substitute?  

Finally, is there a way to “re-charge” or “re-fresh” the magnets?  

Thanks for any advice/information you can provide.

Craig

[Gator Bob]

I am new to this board. I am looking for some information on the K&B Challenger motors

Welcome!
 

I recognize that there are two main types the Challenger, and Super Challenger. I do have Challenger motors in either black or white frames, but internally they look identical.

I really like the simplicity of these motors. They are easy to disassemble for such maintenance as polishing the commutator.  Over the years I have picked up a number of the Challenger Motors. It is rare that one wont run with minimal maintenance, except if the magnets have lost all of their magnetism (heat?) or there is some mechanical issue with the armature.

Not from heat, from disassmbly.
 

All of my K&B cars (1/24) have the Challenger motor. I have swapped out Super Challenger motors from cars that have had that motor. Mostly I want the cars to be even competitors with each other.

On my small track that motor works perfectly. The Super Challenger motors, however, do not like that track. The small track is powered with 14.8 volt wall warts which I believe are rated around 1 amp. The Super Challengers run much slower than the Challengers on the small track.

 
Not enough current available ... BTW: wall warts' output is not very 'clean' DC... bad for magnets, too.
 

On my larger track with a higher amp regulated power supply (but still usually set at 12 volts) the Super Challenger motor is OK. No great shakes, but OK.

I believe the Super Challenger is rated at 6v, while the Challenger is rated at 12v. I could be wrong. My first question is, why are the Super Challenger motors slower than the Challenger motors at a given voltage? I would think they should be faster.  Actually I would appreciate any information about the differences between these motors especially in terms of electrical needs/performance.

Secondly, while I have a couple spare brushes, I have not found a source for them. Any ideas for a substitute?

Check on eBay... if no luck I have NOS K&B parts for these motors.
 

Finally, is there a way to "re-charge" or "re-fresh" the magnets?

Yes, we call it zapping. Do you have a commercial raceway near by to perform this service?

[Gary Bluestone]

I believe the BIG difference between these motors was just the commutator and brush set up , the Super being more conventional and supposedly better.

Besides that you may notice that some of the Challenger plastic side plates are slightly different, in that the 1/32 version has the axle hole closer to the bottom allowing the use of smaller wheels. When I tried swaping a 1/24 motor in a 1/32 chassis, the chassis hit the track.

Not sure if the magnets lose strength through age and concussion too, but remagnetizing involves placing the magnets momentarily into a large magnetic field in an electro magnet. Some model train shops have these as well as raceways.

[TSR]

Gary,

The windings on the Super are different too, using less turns of a larger wire.

P

[don.siegel]

I believe the Challenger with the white endbells was the original version, followed by the black. Haven't run these enough to know if there's any performance difference. Anybody actually measure resistance on these, or find a difference? 

 

K&B also made a conversion kit to turn a Challenger into a Super Challenger. 

 

According to a couple friends here who loved the Challenger type motors, the Super Challengers were very uneven - some not very fast and others almost on a par with a 36D. Of course that was all 30 years after they were built too, so the magnetism may come into it...

 

They are very practical and the K&Bs are steady performers.

 

You might need a power pack with at least 3 or 4 amps for the Supers... especially with two on the track at once. 

 

Don  

[TSR]

These motors were designed by none other than Derek Brand, effectively the inventor of the HO-scale slot car. They were entirely American and built in West Hempstead. I never had one bad, but anytime you take one apart, it WILL require re-magnetizing.
 

[gluebomb]

Hey Craig

 

I'd concur with Don here, have found the Super's pretty uneven but the odd one is a bullet..

Weak magnets are I think are the most obvious cause for a poor runner, a lack of current will impair the hotter Super challenger motors also; I suspect you'll lose some of the magnetism if you totally disasemble and remove the magnets from the poles when pulling the arm but might be wrong - I know for a fact they run pretty badly (ahem) when you put the magnets back in backwards though...

 

A quick fix for weak mags might be some small neo magnets placed at either end on the outside ?

 

Don't know about brushes offhand but reshaping 16D mabuchi brushes to fit would likely work but be a pain, sourcing them elsehwhere is maybe a better bet - some of the older railway motors take a cylindrical brush also. If you're really in a pinch you could experiment with some 4B graphite lead for a mechanical pencil - no experience with this but am told it works so might be worth trying...

[Lone Wolf]

Welcome! I like these motors because they produce good torque over a wide range. I have used the standard Challenger for hard body builds and raced them on commercial tracks. They run very smooth and are fun to drive, not the fastest out there but perfect for what I am using them for.

 

Also, I have found the K&B tires with a little sanding to be excellent performers allowing just a little slide.

[Zapf]

Wow!  Great information. Thanks guys!  And thanks for the welcome.

 

I had no idea disaasemby would be a problem, Bob and Philippe. With one exception, so far I have only taken the side plate (with the brush holders) off the motor to clean the commutator. I have left the rest of the motor (magnets, frame, armature, back plate) intact. Hopefully that will have protected the magnets some. They all still run, so maybe I got lucky in not completely taking them apart. 

 

Don, I do have one of those conversion kits from back when I bought a bunch of K&B parts from EJ's. Interesting that there is such variability in those motors. I have only tried a couple and maybe they were poor examples.  And, as some of you have mentioned, the weak power on my small track probably didn't help. 

 

I had not noticed the different heights of the axle holes before, Gary. Now I do. Thanks.

 

That's an intreresting idea about putting neodynium magents on the outside of the motor clips to boost the magnets, Simon. Have you tried this? I certainly have lots of those since I run non-magnet on other cars. Also thanks for the brush ideas. I have some "O" gauge brushes that are much too large. I hadn't thought of hard pencil lead.

 

I have checked eBay for K&B brushes without finding any, but will check periodically. I'm OK for now, but if I need some in the future I would appreciate your offer Bob.

 

Joe, I plan on using the Super Challengers exactly for what you did - to power hard bodies on my larger track with the bigger power supply.  As for tires, I have had mixed results.  Some are very hard and even with sanding run poorly.  I believe they have just dried out too much.  I have had good results with some NOS sets I have purchased.  I wish I could find a chart of K&B tires and wheels somewhere.  There seems to be lots of dufferent part numbers on tires for sale on eBay, and I find it a little confusing to know which tires might work for which wheels and for what surfaces.

 

I don't know of any commercial raceways locally, I might check with the local train ships.  My experience with trains has been mostly with vintage AC motors, which of course don't use magnets.

 

Thanks again guys.  Very helpful.

[don.siegel]

Paul Gage up in Canada makes repro urethane K&B tires that will work well on your plastic track; also Ortmann tires, which I think are sold through Electric Dreams.

 

Theoretically, if you don't break the magnetic field, your magnets shouldn't lose too much power. Rick (DC65X) has done a lot of magnet measurements here on Slotblog and that will give you an idea of the losses involved, even though he didn't specifically do a Challenger.

 

When I asked a couple model train shops here (Paris), they just laughed and said, "We haven't used those kinds of motors in years", but maybe you'll have better luck! Some places will do mail order too, like a few raceways in California, but don't remember names offhand.

 

Don

[boxerdog]

Old-school auto electric shops that work on speedometers and/or magnetos may be able to zap the magnets as well... the Supers should be much faster,

[Zapf]

Thanks, Don. I have ordered some Paul Gage tires for another car. I'm thinking I'll just have to order several types from him for K&B cars to see which tires fit which wheels.
 
I agree, David, that the Supers should be faster. I think I understand that the reason they aren't on my small track is because of an inadequate power source. With modern 1/24 cars (e.g. Carrera vs BRM) a lower voltage motor will spin faster than a higher voltage motor at a given voltage setting. This doesn't seem to be the case with the Challenger (12v) and Super Challenger (6v) motors I have.  Maybe motors were rated differently in thos days. Philippe mentioned a wire size/winding difference which probably affects the rating as well as the necessary power requirements.
 
As for magnet zapping, I have another question. Simon suggested trying small neo magnets on the outside of the motor magnets. I know very little (very very little) about magnetism. Would leaving some powerful neo magnets attached to either end of a motor for a few days re-fresh the actual motor magnets. I guess I could experiment with that a little. I have a Magnet Marshal that could help in the measurement. 
 
Don you mentioned Rick having dome some experiments with magnets. How could I find his posts? After sending this I'll try "search" so may find them that way.
 
Thanks again, guys.
 
Craig

[Cheater]

Craig,

Rick's display name here at Slotblog is dc-65x.

Do an advanced search by poster's name and be sure to select Display Results "as posts", as the default is "as a topic list".

To enter the advanced search, click the little gear icon to the right of the search box.

[Zapf]

Thanks, Gregory. I found his posts. Lots of good stuff.
 
I specifically read the one on magnetizing the Pittman motor. Very interesting, as were the comments to the post.
 
I will not likely be able to afford a magnet zapper. I might check out the suggestions several members made about "shops" that might do it; or search for an alternative method.

[gluebomb]

Hey Craig,

The rating by voltage bit is better explained in a post by Gary in this thread:

http://slotblog.net/...tors-and-volts/

Basically a marketing tool at the time, ie "standard" motor would be the 12, hotter would be 6, 4.5, 3 volt etc...

I've had ok results with the neo magnet trick, mostly on old Kemtron motors - look around though as pretty sure guys that favor some of the old Pittman style motors have used it otherwise. UK train guys might be a good go-to for remagnetizing or suggestions; I know the old Dublo units needed their chassis re-magged frequently before the advent of neo magnet replacements but likely a few purists out there still providing the service.

Let us know what you find ! I've a few of the standard to super kits with the different side plates and hot arm but the last one I built up promptly became a little space heater of woe and melted (most probably due to weak mags) and my enthusiasm for the hotter challengers waned a bit - would be cool to build some up though...  The Paul Gage tyres are excellent for what you plan on doing and pretty sure he does some specifically for the K&B's.

Cheers !

S.

[gluebomb]

Hey Craig - Just pm'd you re: brushes i found online...

[Zapf]

Hi Simon,

 

Thanks for the brush resource.  I will order a set and see how they work.  I believe the Challenger and Super Challenger brushes are slightly different diameter, so I'm hoping they are the former.

 

Thanks also for the info on the motor voltage.  I'll check that link out.

 

I tried the neo magnet idea without success.  I think the main problem is that the neo magnets were so strong that they immediately clung to the unmagnetized motor magnets without regard for polarity.  Plus I'm not sure that I would know how to do the polarity right in the first place.  I did read another post about using neo magnets to charge weak magnets.  The suggestion was to slowly move the neo magnet toward the weak magnet so that it would orient correctly.  The motor magnets I have are so bad they are basically lumps of metal and do not have enough strength to orient the neo magnet correctly.  At least that is what I think is happening.

 

I did find a shop that stated they zapped magnets.  I exchanged a few emails with them and included pictures and descriptions of the Challenger motor.  They politely laughed.  I think they deal more with the superfast type of motors used at commercial tracks.  So, no luck there. 

 

Since for my purposes, the Challenger motors work so much better than the Super Challenger ones, I have done the "reverse modification" on a couple.  I used the armature and plates from a non-functioning Challenger in the magnet/frame from a functioning Super Challenger.  Worked a charm.

 

I am ordering several of the Paul Gage tires.  Since I have found nothing close to a K&B tire size resource, I'll just order what he has and then figure out which ones fit which wheels.

 

Finally, as an aside, I found some really neat 1/24 bodies that are re-issues from Tamiya.  The chassis mounting posts are very similar to K&B.  I think I have found a way to use the K&B chassis with these bodies.  Now if I can just fix up enough motors to run them.