Caring for your new Brushed motor

[JohnRobHolmes]

The most up to date information will always be listed on my site, so check here first-- http://www.holmeshobbies.com/blog/?page_id=373
**For a primer on the parts of a motor, read this: http://www.rccrawler.com/forum/showthread.php?p=919711#post919711**
**For a discussion about tuning and maintaining a motor, read this http://www.rccrawler.com/forum/showthread.php?p=1663074#post1663074z **

I have had many questions on how to care for your new brushed motor, especially the Cobalt Puller. Since it has a 7 slot armature the brush orientation is 90* offset from your typical 3 slot 540 motor. It is very hard to take a picture of the motor as my eye can see it, but hopefully this will help.

As an adjustable timing motor, the Cobalt Puller and any other MOD motor does not have "forward" or "reverse". You can rotate the endbell 180* and effectively swap the rotation, or just swap the motor leads. When a motor has neutral timing, it runs the same speed in forward and reverse. Advanced (positive) timing makes the motor spin faster, Retarded (negative) timing makes the motor spin slower. Small variations in the brush and comm condition can effect this slightly, but it is nothing to worry about. IF YOUR MOTOR THROWS SPARKS YOU HAVE IT TIMED NEGATIVELY (retarded). This is important, as negative (or retarded) timing will make the motor wear out very fast. A motor with about 7* of advanced timing will have the longest lasting brushes, but since crawlers need both forward and reverse power we normally time at 0*, otherwise known as neutral timing.

You will always want to run zero or advanced timing. The Cobalt Puller runs very well with zero timing. To advance the timing, rotate the endbell in the opposite direction of the motor rotation. If your motor rotates clockwise for forward locomotion, rotate the endbell counterclockwise in relation to the can.

Care

First, it is a good idea to inspect the motor before and after every run. You may want to check the screws on the endbell. If they loosen you can damage the motor during a run. Loctite is a good idea, only a small amount of medium strength on the screws is needed.

The comm and Brushes should be in good condition. If the comm is black or purple or burned looking it is time to cut the comm and file down the brushes a bit. Running in water or dusty conditions will damage the comm quickly.

Second, always keep an eye on motor heat. In general, 160* F is an acceptable max temperature for motors and most ESC's. You can go higher, but depending on the grade of magnet you may damage the motor and weaken it.

Third, be sure to clean your motor periodically. You will need to use an electric motor specific cleaner. Most hobby shops carry it, or you can search Google for "electric motor cleaner". After cleaning lube the bearings with a light oil such as 3-in-1 or a motor specific bearing lubricant.


Timing

Now, on to timing your Cobalt Puller.

Amp draw method-- Loosen the endbell and put low voltage to the motor with no load (3v is easy to work with if you have it), rotate the endbell just a bit back and forth until the amp draw is lowest. Retighten.

If you put the voltage to the motor in the polarity that you will use it, it will be most accurate.

The brushes line up with the Screws on the endbell. At neutral timing the brushes will be between the magnetic north and south. You can visually line up the brushes, or you can use an ampmeter to help. At Zero timing the motor will draw the lowest amperage. NEVER run the motor with retarded timing, as the brush will throw sparks and eat the comm quickly.
1. Screw on the endbell slowly being sure to not damage the threads.
2. Use a bit of plastic or wood to seat the brushes onto the comm (I use a sharpened chopstick). If you use metal it will damage the brush and comm.
3. Screw the endbell down until the armature does not wiggle in the motor case, then back it off 1/4 to 1/2 turn until the brushes line up.
4. Tighten down the endbell screws (blue loctite will help keep them tight) being careful not to change the timing. The endbell screws on a Cobalt Puller take a 2mm allen wrench.
5. If the motor rotates the wrong direction either swap the motor leads or rotate the endbell 180*.

Now bolt that motor in and beat the snot out of your rig!!
Any Questions, post em up!

 

[JohnRobHolmes]

Motor Break In
Place the motor on a stable surface, or remove the pinion if motor is installed in a vehicle. Allow motor to spin with no load. Apply between 2.5 and 3 volts to your motor for three minutes with zero or six degrees timing. The brushes should be seated with at least 90% of the brush face touching the commutator. Motors slower than 1,000 RPM per volt may need more time.

Timing your motor
Unless specified at the time of purchase, your brushed motor will have neutral (zero) timing and operate properly during clockwise (CW) and counterclockwise (CCW) rotation. When the motor will rotate in a specific direction, slight timing advance is suggested. Lower priced and small motors wear out quicker at zero timing because of small variations in build, so advanced timing can save your comm and brushes. You can check the timing advance in many ways, we suggest using more than one method until you are familiar with the task. :

The motor will spin faster “forwards” as compared to “reverse”.
The no-load amp draw will be higher than neutral timing.
A visual inspection reveals advanced brushes.

You can check to see if the motor spins slightly faster in forwards direction with a tachometer, or with motor sound. A faster motor or machine will generate higher pitch noise.

Timing the motor with amp draw requires an amp meter. Loosen the endbell and spin the motor with low voltage. We suggest 3 volts for easy motor handling. Rotate the endbell a few degrees until you find the lowest amp draw. This is neutral timing, and may not be exact visually because of motor construction and brushes. 10% higher no load amp draw in the advanced direction is a safe setting.

To advance the timing visually, rotate the brushes (endbell) in the opposite direction of motor shaft rotation. This energizes the segments sooner during rotation. If your motor rotates clockwise for forward locomotion, rotate the enbell counterclockwise in relation to the can. Most Holmes motors have marks on the can and endbell that indicate 12, 24, and 36 degrees for CCW pinion rotation. About 7 degrees of timing is what we have found to be an optimal balance of brush life and reverse/ brake performance below 20,000 rpm. 6 degrees is easy to visually set on most Holmes motors.

The yellow markings signify where the screws line up. There will normally be a dimple in the can.
The red line signifies brush orientation for zero timing. There is generally another dimple in the can, and is dead center on the magnets.

Reversing the power leads or rotating the endbell (and thus brushes) will reverse the motor rotation. This holds true for any motor.



Additional reading:
http://www.misbehavin-rc.com/pit-lane/motor-timing/g-motor-timing.asp
http://www.marcee.org/Articles/TimingBrushedMotor.html

 

[tsaun987]

Awesome, thanks for that JRH.

 

[Grizzly4x4]

Great writeup John!

I've been using HPI Stunt Spray to clean my Slash motor.
Should I use a dedicated electronics cleaner like I see at the auto parts store on my HH motors? Or is there not really much difference?

 

[braceysdad]

So your saying that when I occasionally wash my rig with a water hose is not sufficient?

 

[JohnRobHolmes]

A normal degreaser will eat at the epoxy or conformal coating of electronics. It will soften it and can cause shorts. The HPI stunt spray is not a good electronics cleaner unless it says for electric motors on the side.


A water hose is great if you re-oil and dry everything afterwards.

 

[Grizzly4x4]

A normal degreaser will eat at the epoxy or conformal coating of electronics. It will soften it and can cause shorts. The HPI stunt spray is not a good electronics cleaner unless it says for electric motors on the side.

It does say that it's safe for electronics. I don't remember if it specified "electric motors".
I'll buy something made for electric motors to take care of my HH motors.

 

[karlos]

Can you use electrical contact cleaner, or is what you are refering to something different?

 

[Grizzly4x4]

Can you use electrical contact cleaner, or is what you are refering to something different?

This is what I was thinking of using. It's easy to find at the auto parts stores.

 

[Rubbaneck]

I would stick to local hobby shops for your motor spary. It may cost a dollar more but it's designed for all out stuff. You can clean your lexal and plastic with most hobby brands which is a good benefit. Most important is the endbell from these motors are plastic. I've used CRC like was GRIZ is looking at and just beware of things melting our cheap plastic's we use in R/C, compared to automotive plastics.

 

[Grizzly4x4]

I would stick to local hobby shops for your motor spary. It may cost a dollar more but it's designed for all out stuff. You can clean your lexal and plastic with most hobby brands which is a good benefit. Most important is the endbell from these motors are plastic. I've used CRC like was GRIZ is looking at and just beware of things melting our cheap plastic's we use in R/C, compared to automotive plastics.

Thank you sensei, I will look at the hobby shop for something. "thumbsup"

 

[1BadJeepBruiser]

You guys definitely want to use Motor spray, I have used Dynamites stuff in the past and it works well. DO NOT use brake cleaner or other stuff like that, as already said it can weaken the bond on the magnets which is obviously NG.

Water is an abrasive, an old truck is to break a motor in using a cup of water. Excessive running in water will wear down the brushes and comm. If you do a lot of running in water, cleaning out the motor and re oiling the bearings frequently.

-Mike

 

[binaryterror]

There is nothing wrong with Lectra-Motive, its some amazing stuff for all electronics and motor safe. Cheaper and I prefer it to "hobby" motor spray.

 

[binaryterror]

Water is an abrasive, an old truck is to break a motor in using a cup of water. Excessive running in water will wear down the brushes and comm.

That is not true, the reason that trick was used was to lessen the arching of the new brushes. It's still the rotation on the brush with the comm that is wearing the brushes in not the Water. Of course the water lowers the break in temps and washes the carbon away.

We used to do this to the 540 Silver can Tamiya motors to have the best motors in racing.

 

[1BadJeepBruiser]

That is not true, the reason that trick was used was to lessen the arching of the new brushes. It's still the rotation on the brush with the comm that is wearing the brushes in not the Water. Of course the water lowers the break in temps and washes the carbon away.

We used to do this to the 540 Silver can Tamiya motors to have the best motors in racing.

Are you saying that water is not an abrasive ? or are you saying that running the motor in water over long period times will not wear it down?

I know why people break the stock motors in, in water, I used to do it myself. But I am still certain that water is an abrasive regardless...

 

[binaryterror]

Are you saying that water is not an abrasive ? or are you saying that running the motor in water over long period times will not wear it down?

Yup, distilled water is not an abrasive. It will still wear if you ran it for hours however no more than if you ran it dry.

 

[supercrawlerfreak]

its not the water its the minerals in the water, so yes if you ran them in distilled water then it wouldn't wear any faster, but how many rigs have you seen in perfectly clean distilled water:lol: its usually muddy dirty nasty water.

 

[bigflex]

its not the water its the minerals in the water, so yes if you ran them in distilled water then it wouldn't wear any faster, but how many rigs have you seen in perfectly clean distilled water:lol: its usually muddy dirty nasty water.

really! I only run my rig in distilled water and never in mud.:ror:

 

[NeXt559]

any tips on breaking in a new brushed motor?

ive seen some guy on youtube letting a motor run in a cup of water to break it in (dont think i'll ever try this method, im pretty pron to electicution and im sure alot of other people are also)

at the moment i run it at about 25 % for about 10 min.
is this right?
as w/ a new car (w/ a 4 banger); you should not rev your engine past 3,500 rpm untill the first 3,000 mile oil change. am i wrong in thinking along these lines?

 

[JohnRobHolmes]

For a crawler it isn't a big deal to break it in unless you are running a faster motor like a 35t or a Handwound that will produce big power.

Running in water keeps it cooler and allows faster break in without burning stuff up. Low rpm for longer periods can accomplish the same thing. I don't recommend water break in.