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Old 02-12-2007, 09:56 AM   #1
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Default Electric motors?

Ok so I tried to search but the search function doesn't seem to be working ATM.

So I'm new to electric and cant really find much info on the general knowledge things about electric motors. I understand how motors work with magnets and brushes but what I dont know is the differences.

What is the difference when people say "stock" or "19t" etc?

What does it mean to cut the comm?

Are there any websites out there or threads here that explain the basic ins and outs of electric touring? I'm reading through that great site with tons of info on the mathematics behind cars.

Thanks,
Jim
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Old 02-12-2007, 10:49 AM   #2
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Ok I'm going to try to keep this as short as possible. Motors for electric start break down in to two different styles; brushed motors and brushless. The older brushed motors are what have been around for a while and because of this most racing (not all) have been broken down in to classes according to this. Brushed motors have windings around the armature in the form of a copper wire. The number of winds classifies the motor. For stock the motors must have 27turns of winds. The less winds the faster (in general). 19turn class has 19 winds. Because these motors can be tuned to be faster, organizations in racing have put rules as to what you can do to make them run faster so that the racing is closer and the field is on a closer playing field. The way these motors work is basically a small electric motor (like the one in your washing machine), that has a positive and a negative side fired by two brushes on each pole (the brushes aren't how you would think of a traditional brush). They fire on the spinning arm by contacting the Commutator (long for comm). Since it contacts the arm at the comm, it wears the comm out and over time (depending on how powerful the motor is) you will need to rebuild the motor; this can include replacing brushes and skimming/cutting the comm. A fresh built motor that isn't worn out is faster (but it's relative). Stock is by far the biggest and most participated in class. It may seem slow on a open street, but put that speed down on a twisting, tight track and it will seem very fast. Brushless motors is fairly new to our hobby. It has been around for a while in other applications, but is just coming up to speed in ours. Because it works on different technology, it needs different electronics to work. Also, since it is new, rules from organizations are in the process of reacting. Most big races don't allow them in stock and lower classes (they are now allowed in modified since speed isn't regulated) since they can't replicate the same speeds as the brushed classes (similar, but not the same). Club racing locally tend to be more leniant in rules, so some have adopted the new technology earlier in an effort to increase participation at the expense of leveling the playing field. Also, brushless has less maintenance (in general). Check with your local club about racing for class separation and rules.
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Old 02-12-2007, 02:33 PM   #3
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Awesome info, thank you very much that cleared up alot.
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Old 02-12-2007, 02:55 PM   #4
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brushless stock motors are also now aloowed by roar. the difference is that in a brushed motor your sending electricity to the brushed and thus the armature. once energized that electricity cuase the arm to rotate within the magnet field. with a stock motor it is timed at 24 degrees and 19t motors most are also preset to a specific timing as well. but there are some that you can adjust the timing on. from there all lower turn numbers you can adjust timing. by doing that you can get more torque,midrange, or top end out of your motor depending on what timing you give it. when the cans are built they have to send a super high voltage zap to the magnets to actually magnatize them. depending on where they do that on the can in relation to hands on a clock you can slightly alter the timing of a stock motor with rotating the hood. thats another reason why the stock motors from aftermarket companies are faster. the magnet field is in like an oliptical orbit,in a sense, around the can of the motor. thats why the arms spins when it is electrically charged.

where as a brushless motor is the opposite, the magnet rotates inside of the can. and the can is lined with electrical windings. that is why there is a sensor wire on those motors, so it can tell the esc where the arm is in relation to the timing mark and its rpm so as you operate your throttle the motor is doing as you are. since there is no actual contact between the arm and the brushes,or can. but after time a brushless will build up with grime and dirt inside of it. while there is no comm to cut or brushes to replace it is less maintaince but not zero. you should open the motor say once a month if your running three times a week racing lets say. and clean the rotor and the bearings, and wipe out the inside of the can.

its kinda hard to really explain it well without writing a book, but i hope this info and the other posts help you out.
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Old 02-12-2007, 03:28 PM   #5
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Actually you can find any wind motor in adjustable timing, you would just have to do some research (though these kind of adjustable timing for motors are rarely legal for any kind of racing). The organizations limit the timing and other rules like rare earth magnets, armature shape, weight, bearings, etc. in order to try and limit the tuning a racer can do to gain an advantage. BTW, altering the magnetic field by advancing the timing, etc., is illegal. Magnet zapping is usually done as the magnets lose their strength. The zap will bring the magnets back to their full strength, but can not increase them past their original strength.
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Old 02-12-2007, 03:29 PM   #6
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Don't mislead this guy. Your statement that brushless can't put out the power of a brushed motor is not true. The newer systems out like the mamba max 7700 and the novak 3.5 will put out more power than a brushed motor unless you are a top notch motor tuner . I used to run mod brushed motors and could never get the power that i'm getting with the brushless systems.
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Old 02-12-2007, 03:32 PM   #7
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Quote:
Originally Posted by latemodel13
Don't mislead this guy. Your statement that brushless can't put out the power of a brushed motor is not true. The newer systems out like the mamba max 7700 and the novak 3.5 will put out more power than a brushed motor unless you are a top notch motor tuner . I used to run mod brushed motors and could never get the power that i'm getting with the brushless systems.
Let me clarify, "they can't replicate." Sure there is a difference in power, and in many cases more power, but impossible to replicate. My intention wasn't to mislead, sorry if that's how it came across.
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Old 02-12-2007, 04:22 PM   #8
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Quote:
Originally Posted by AzBobby
brushless stock motors are also now aloowed by roar
where is this written by ROAR?
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Old 02-12-2007, 04:39 PM   #9
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brushless is like a 7 turn i was told and the weight makes a tc mested this is what i was told and thats why alot of ppl dont run them much and ya this is what i was told too.
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Old 02-12-2007, 05:16 PM   #10
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Quote:
Originally Posted by timmay70
where is this written by ROAR?

the way that the rule was written for 2006 it includes all brushless systems.
that in part is why novak developed the the 13.5 i think it is. the one equal to a stock motor. roar mandated that all the manufacturers of brushless systems provide in writing what each of their motors are equal to in a brushed motor sense, as well as the all had to hook into the esc the same way. so you could run any brand motor with any brand esc, just as in a brushed motor application. that was one reason why it took so long for them to become legalized. roar is at least pro cost savings to the racers. and over time a brushless is less cost than brushed.

i don't think anyone has mislead this guy in any way that brushless is faster or slower. they make power in different ways, kinda like two stroke and four stroke dirt bikes. it still all comes down to your driving and throttle control. i know a number of top pros who don't care for brushless motor systems. they do seem a bit more popular in on-road than off, but i do use one in my 4wh off-road.
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Old 02-12-2007, 06:42 PM   #11
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The 13.5 is close but not the same. Way more torque. Not as noticeable in Offroad, but Onroad it is a huge advantage.
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Old 02-12-2007, 07:34 PM   #12
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Quote:
Originally Posted by edseb
The 13.5 is close but not the same. Way more torque. Not as noticeable in Offroad, but Onroad it is a huge advantage.
it does perform better but it is classified as stock, so it is legal.
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Old 02-13-2007, 10:44 AM   #13
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Quote:
Originally Posted by timmay70
where is this written by ROAR?
I'd like to see that too. Also, are they legal as a separate class, or legal to run with the brushed stock motors? I can't believe they are claiming they are the same speed, they're not even close. What about sintered rotors in those?
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Old 02-13-2007, 12:16 PM   #14
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Quote:
Originally Posted by AzBobby
brushless stock motors are also now aloowed by roar.
Brushless motors are allowed in mod only for ROAR ruled events. Not stock.

See the 2007 rulebook page 40 2007 ROAR Racing Rules

"8.7.5.0 Brushless Motors are approved for modified racing only."

This was the same way it was way back in 2006.
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Old 02-13-2007, 12:24 PM   #15
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Quote:
Originally Posted by Rysuleod
Allowed in mod only. Not stock.
Exactly. I went back to the ROAR site after reading this just incase something was announced that I may have missed. The stock motor rule stays the same as it always has been. Brushed only, fixed timing, and only the motors on the approved list. If something has changed within ROAR, I hope one of the Officials will step in and correct this.

Just because a company that produces a motor claims that it is a 'Stock' motor doesn't make it legal for 'Stock class racing'. The technology still has to be defined for Stock class racing, then the motors that will be allowed have to go through homologation. It will be a while before you see these motors legal for stock class racing.

However, this does not mean that local tracks/clubs will not allow these motors for Level 1 and/or club level racing events. Check with your track of choice to see if these are allowed for stock class racing before dropping your hard earned cash on such a system.
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