Stock motor questions
 

I have a few 27 - turn motor questions. I've searched and really haven't seen topics posted about this aspect before.

In regards to:

Does anyone know what Armature shafts are polished by, when a motor company states 'Polished Armature Shaft'?

What does aligning Brush Hoods entail?

Stock Motors
 

Motors can be complicated, it's like anything else the more you work with them the more of a feel you get for them. The best advice I can give is this:
http://www.bigjimracing.com/ This is Big Jim's Website, I believe he passed a few years ago but he contributed allot to what motors are today. Big Jim put out a book called " Big Jim's RC Motor Black Book". I had to go look at the actual name but I still look through it for reference when I need too. The book is a little out dated since it's about 6 years old but it's a fantastic place to start. It give allot of nice tips that I still do religiously. Happy Racing!!!

Hi Sgrios,

I will do my best to go over this as quickly and easily as possible =)

Polishing the shafts basically entails either using an emery paper or cloth with a high quality metal polish and making the contact areas where the shaft rides on the bushing mirror smooth. One of the key areas to building a fast motor is the reduction of friction.

Aligning brush hoods is a bit more complex. There are several ways that it can be done and several conflicting opinions. Big Jim always endorsed the concept of aligning the hoods so that the actual contact patch of the brush was seated squarely on the comm. To do things this way you need to run the motor in for a few seconds until it creates a wear mark on the brush and then adjust the hoods until that wear mark is dead center on the face of the brush. The idea here is that the brushes shift slightly inside the hoods when the motor spins up so just setting them 180 degrees apart isn't really accurate in relation to how the brushes actually make contact. We have tried many different methods and the Big Jim way always makes good power. It takes a little practice but it pays off in the long run.

Feel free to hit us up with any other questions, always happy to help out.

Nick

Team Kwik :blush:

With that type of response... your customer service must be amazing.
Thank you very much. I think I found a new motor/battery supplier =).

What grit Emery paper do you use? Fine?

Precision Spaced Armature.. what does that entail? What gauge are you using to check end-play? (If thats even what your checking.) Teflon motor shims?

We tend to prefer going with a high quality liquid polish, if you take much material off that shaft during this operation you will develop way too much play. Too much of a good thing =)

Shimming a motor involves getting the stack as close to centered in the magnetic field as possible. Assemble the motor with no shims and pluck and spin the shaft noting where it wants to rest on it's own. The object is to shim the motor so it stays in that location. We like to see a little bit of wiggle and we do use teflon shims as the outermost shim, the only area you need teflon is against the bushing.

Glad to help,
Nick

What type of shims do you use if it's not against a bushing?

What motor cleaner do you all use when you build/rebuild motors?

Do you epoxy the motor to re-balance it? Also, how do you check balance in the first place? (Maybe a dumb question there)

Are your firewater motor drops for brushes only? If it's added to the comm, how much additional wear would the end-user see?

Thank you very much,

Jeff

Hi Jeff,

We use standard metal shims, you can find these on our website in a few different sizes. As I said before we tend to just put a teflon on the outside and take up the rest of the slack with metal. You will find that the teflon shims squash under racing conditions so they need to be replaced and shouldn't be relied upon for much in the way of structural integrity.

For motor spray we use whatever is available at the local hobby shop honestly.

Balancing a stock motor beyond how it's delivered from the factory isn't something we do nor is it something that's considered legal.

We have the Firewater drops to be used on the brushes and the Revolver oil to be used on the bushings. Firewater will actually extend the life of your comm and brushes by adding lubrication and preventing burning/glazing.

Nick

Thank you once again nick.

Last question I can think of for now, how do you check if the motor is at 'true' 0-degree(s) timing?

Checking the arm is something we do here in the shop to ensure the motors we send out are all legal. It requires a good quality jig and isn't something I would recommend for your average racer. I know there are several tracks around the country that have these tools and I am sure they would be more than happy to let you check your arms on them. In the end it's just not cost effective to spend a few hundred dollars on a tool like this unless you need to check a lot of motors =)

Nick

Thought of more questions. (damn)

Would you recommend Big Jim's RC Motor Black Book?

What dyno do you use to test/tune your motors?
What comm lathe?

Thank you yet again.

Big Jim's book is a great resource if you are looking to learn as much as possible when it comes to motors. As mentioned before it's a bit dated but still a great read.

We use the Competition Electronics TurboDyno, again this is honestly one of those items that's not very cost effective. Shawn hasn't ever really used the dyno at large events, it's usually just there to have as a good way to diagnose problems. All of the motors we sell are tested on the dyno mainly for this reason, we do ensure they fall within a certain set of specifications before we ship them out but in reality that is achieved on 99% of motors before they ever touch the dyno. For the average racer I would have to say the track is your best dyno, take the time to make changes and test them out on the track. In time you will find there isn't a dyno that can replace it.

We have a few Fantom lathes, truly the best machine you can buy and it has the price tag to reflect it. These lathes are all machined from one piece of material which really helps to ensure alignment. I have seen many bolt together lathes making some of the most crooked cuts. If you cut a lot of motors it's well worth the investment. As with most other items this isn't something you need to run out and buy. Chances are you have a local racer with a lathe like this who would be more than happy to help out =)

Nick

i cant seem to find a copy of big jims book.....Trafford publishing website says "404 Error

Sorry, the page you're searching for can't be found."

does any1 actually have a copy of this.....or know where it can be found??

thanxs....

wog

Amazon!

The whole book is pretty much up on hobbytalk.......its techincally out of print last I checked.......people were paying like $50+ a copy on ebay not to long ago......wonder how much I could get for my copy thats signed with a message from Big Jim (not that I would ever sell it).....


As for lathe's....if it cuts straight yer good to go.....fantom is the best, but they are $400 lathes...and hard to get.

As for a dyno, save your money......the CE dyno is the best, but is still very unreliable.....at this point, until a dyno comes out for brushless and brushed ( I know the CE can do it).....I would not buy one....

Later EddieO

Team kwik... how much do you charge for Blueprinted stock motors???