391 replies to this topic

[Bazzie]

I think the new motors with the vertical brushes are the answer. We should not have the overlapping problem anymore, which is definitely the biggest cause of escaping smoke...

On the dirt one, I think it may occasionally be an issue but much less so than the overlapping brushes. Not discounting it totally


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[swodem]

Sorry, typo - non-run-in, I will edit my original post

On whether the brushes had been run in, I was told by the driver he had done nothing to it, in fact he never does, so unless he is a compulsive liar, or Dan Da Bella decided to do him a favor and personally run in his motors before sending them out, that's how I know.

I guess under cross examination I would have to concede that there was a chance someone could have crept in and secretly inserted worn in brushes.

If you cite the sample-of-one that one guy posted he had a pushstart that was fixed by rubbing the brushes back to having flat tips, you must also accept that doing nothing eventually fixes them too cos that's what happened to my motor

So....which is it?

Our mates in Wellington are doing exactly that (rubbing their brushes back) and I still hear they have the problem and three of their burned out motors are heading my way for investigation...

Just sayin'






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[havlicek]

I guess this must be just the way the picture looks, and quite possibly besides the point, but dang the motor shaft sure looks way-the-heck off center in relation to the bushing.  Of course, some sort of brush problem could lead to overheating and melting even, but I can't imagine how any kind of heat (short of a welding torch) could possibly account for what sure looks like the shaft having moved way to the right in the photo above.  Like I said, probably just the way the picture came out or something.

[swodem]

It's a long endbell shaft on these motors John and obviously the camera wasn't perfectly aligned looking down on it
With the shallow depth of field in closeup photography (worst view is through the lens before the aperture actually closes down for the shot on an SLR) much if that shaft would just be too out of focus to even see. My ring light is quite bright so I end up photographing using smallest aperture = greatest depth of field.


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[MSwiss]

1-On whether the brushes had been run in, I was told by the driver he had done nothing to it, in fact he never does,

2-If you cite the sample-of-one that one guy posted he had a pushstart that was fixed by rubbing the brushes back to having flat tips, you must also accept that doing nothing eventually fixes them too cos that's what happened to my motor

So....which is it?

3-Our mates in Wellington are doing exactly that (rubbing their brushes back) and I still hear they have the problem and three of their burned out motors are heading my way for investiga
 

1-How long does it take for the brushes to lose their flat spots, when running under load, on the track?

 

2-Way more examples of problems being fixed with cut brushes, or never happening, when run from the get-go, than motors like yours- "fixing itself"

 

3-Are they still having push start issues, or just having their endbells melt, as shown?

 

Motors with cut brushes should run more efficiently, but I've never said it will prevent all overheating issues, especially if the motor is geared aggressively.

 

Also, with the stock hoods, you can only cut / "rub" your brushes back so far back.

 

If you don't monitor them regularly, and replace as needed, at some point, they will be full face again.

[gotboostedvr6]

Steve,

What size pinion and pitch are you guys using? What's your tracks voltage?

Dave

[Zippity]

Mike,

 

Steve is talking about two different racers.

 

Dave, normally 12:37 at 12.4 volts

 

PS Not everyone is removing material from their brushes - I am only aware of one racer doing so here in Wellington

[Trevor Neilson]

Hi Steve. I have no idea of why these motors do it as it was the first time I have ever used one last Sunday at Stu's. but the one thing I did notice was this. When Steve swapped over motors before the race started the new motor sometimes needed a pust start. When someone went to push start it, sometimes when they got a hand got close to it the car would go by itself without them touching it. I got Steve to resolder the motor as there was no play between the spur and the pinion. Once he had done that the motor went fine for 6 hours no no push start problems. . 

[swodem]

1-How long does it take for the brushes to lose their flat spots, when running under load, on the track?

 

2-Way more examples of problems being fixed with cut brushes, or never happening, when run from the get-go, than motors like yours- "fixing itself"

 

3-Are they still having push start issues, or just having their endbells melt, as shown?

 

Motors with cut brushes should run more efficiently, but I've never said it will prevent all overheating issues, especially if the motor is geared aggressively.

 

Also, with the stock hoods, you can only cut / "rub" your brushes back so far back.

 

If you don't monitor them regularly, and replace as needed, at some point, they will be full face again.

 

1. Probably at least an hours track time, the standard brushes will last 6hr continuous running once profiled...

2. Good for them!! If this was so simple, then all motors with fully bedded in brush would do this. Forever. Until remedied.

3. Push-start is the symptom, endbell meltdown is dependent on holding the gas on hard while its in this state. The time this takes depends on available amps.  Really high current tracks might take just a second or two...

[swodem]

Steve,

What size pinion and pitch are you guys using? What's your tracks voltage?

Dave

 

Dave

 

It depends on the size and style of the track. Short and twisty get lower gearing, longer, more flowing get taller. 

So somewhere between 11:37 and 12:35, typically tyre diameter close to 16.5mm

 

Its not too tall for the motors, have run these ratio's for last couple of years. 

[gfox]

What's Bazzie talking about?

"the new motor with the vertical brushes"

[Zippity]

What's Bazzie talking about?

"the new motor with the vertical brushes"

 

Something he read that MSwiss had posted elsewhere

[MSwiss]

I never said a new motor was coming out.

Just some experimentation was being conducted with vertical brushes.

[Samiam]

Flattening the brush face back to new or un radiused condition is the only option if the rules prohibit altering/cutting the brush.

[Fast Freddie]

Sorry guys but Mike Swiss pointed out a mistake I made in post #67.  The last line should have read ", is no reason not to allow the cut brushes.".  My bad, sorry if there was any confusion. 

[Fast Freddie]

One more thing.  What some people call magnet "thump" I call "cog steps".  It's the amount of times you feel a "thump" for one revolution of the motor.  This varies in different motors even motors of the same brand and type.  Some motors have 6 steps some 8 some 10.  This may be a way of telling if a motor is going to have a push start problem or not, by associating motors that have a push start problem with the step number.   There is another way though.  Remove the brushes and springs and free spin the motor by hand.  Do this 8-10 times and each time check where the arm stops in relation to the comm. and brush hoods.  If at any time the arm stops in such a manner that you can see the comm. slots of one segment of the comm. close to or aligned with both brush hoods there is a good chance that motor will develop a push start once the brushes have completely broken in.  It's just a theory but it hasn't failed me yet.

 

Some of you guys that have been melting endbells may have a loose bushing problem.  Glue the bushing in before you oil the motor for the first time.  I use a brand new tube of super glue because it's thinnest when new.  I have also used new Gorilla super glue but it's a little thicker.  Most of the arms in this thread look to be riding high in the endbell, most usually ride low in the can, this can cause excess heat in the bushing if it's not lubed well.  I found that oiling that little white arm washer on both ends of the arm with synthetic oil helps.  In many cases that washer is directly on the bushing.

[swodem]

Hmmm not easy spinning and viewing


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[Bazzie]

Believe me, I know of at least 3
 
PS Not everyone is removing material from their brushes - I am only aware of one racer doing so here in Wellington [/quote]


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[Fast Freddie]

Eben, if you don't have a push start problem with a particular motor it isn't necessary to side cut the brushes for that motor.  It only cures the push start problem on motors that have the problem.  So in lieu of scrapping a motor with push start problems side cutting the brushes allows you to use the motor as it was intended.  It's a cost effective move in the racers favor so why would anyone not approve of it?

 

Steve, your right but it can be done and could save you hours of frustration.  You can spin the motor easier with a gear soldered on the arm or use one of those knurled knobs like what comes on those mini wire brushes used for cleaning out bushing bores, that's what I use.

[gotboostedvr6]

I'm surprised no one questioned the 11 or 12 tooth pinion usage on flat tracks

[Fast Freddie]

My guess would be is they are trying to reduce the effect of the neo magnets.  It could eliminate, or drastically reduce, the use of braking through the controller.  I use very little brakes when using this motor even on a Gerding King.  The magnets provide a lot of brakes until they get warm then you may need to add some in. 

[gotboostedvr6]

You can reduce the braking effect of a motor in more than one way.

[Bazzie]

Freddie, you're right, the problem is that fuses are too slow to catch the 300A that flows so I've seen very expensive controllers blow. Last yr 3 weeks before the nats I put new motors in my lmp and f1 in order to ensure everything is legal. Aligned brush hoods, tightened the hoods so as to get minimal cocking. On the Friday before the nats in free practice, the lmp motor stalls. I complain to the guy I bought it from and he tells me how to reset the brushes to factory condition.

So Ron, by definition, the meaning of 'cheater' is a person who behaves dishonestly in order to gain an advantage. So tell me what advantage am I gaining by going back to factory condition? This year for the nats I'll practice with trimmed brushes and the fit slightly run-in new brushes just before inspection. Cannot be against the rules. Better yet, I'll talk to you about a remit. People have done remits to allow filing of chassis, which at first was actual dishonesty as it could actually give an advantage. So the rules were changed to allow it. This is a silly rule that costs people money and frustrates a lot of people and it does not do anything to level the playing field. It should be a simple process. We're wasting a lot of time that could be better spent to just fix the problem at the root.


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[Bazzie]

Guys, I apologise, I'm making a retraction, by making a more accurate statement:

One person at our club, one week had a stalling motor for one week. He asked me to trim the brushes (implying other people at the club are aware of me altering the brushes). I helped him. I don't know if he's still running the same motor. The other is the one who showed me how to do this - I guess that doesn't really prove that he's actually doing it himself. So make it 1, me...

[Bazzie]

Cheater? I think not - I'm being open and honest about it, for me it's either I trim the brushes on these motors or leave the hobby. I cannot afford regular replacement of motors. Also the intent behind cheating is to gain advantage. This is clearly not what I'm doing, as there is no performance advantage to be gained. Google 'cheater'... I'm merely enjoying the hobby and would like to keep doing so.