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View Full Version : Armature balancer


Team Nissmo
2012.04.30, 08:01 PM
I have been winding motors and built this to balance the armature.

It uses 4 Kyosho stock magnets, 1 gold neo and a cut down safety pin inserted in a stock MR-02 pinion gear.
The trick was to get both sides pulling the same so the pressure on the pin is minimal.
Simple to use the heaviest side always drops to the bottom.

I have been testing all the loose armatures in my box and 3 out of 3 new Kyosho stock motors are perfect.... the used other brands I have tested not so much.

The motor in the pic. below is a 50.5T hemi with about 1* advanced timing (for an xmod)

http://memberfiles.freewebs.com/77/47/38974777/photos/Motors/ballancer.JPG
http://memberfiles.freewebs.com/77/47/38974777/photos/undefined/bal2.JPG

I will be using an Amp meter and a laser taco to test rpm before and after balancing to see what difference it makes.
http://memberfiles.freewebs.com/77/47/38974777/photos/Motors/taco.JPG

color01
2012.05.01, 12:55 AM
Very interesting. So the magnets have enough pull to lift the armature off the ground? How much friction is there on the pin? Is it comparable to or better than a high-quality, non-shielded ceramic bearing?

Team Nissmo
2012.05.02, 12:45 PM
The magnet field suspends the armature in mid air, both sides have the same pulling affect meaning the armature will stay on the opposite side if moved over and there is very little friction on the pin.
I tried a rig using Atomic ceramic bearings but there was still way too much binding.
With this magnetic rig I can spin the armature just by breathing on it so do not think high-quality, non-shielded could match.

Traveler
2012.05.02, 01:01 PM
Very interesting! So what material do you use to add ballast when you need it?

Team Nissmo
2012.05.02, 01:12 PM
I have been using epoxy putty

egonzalez
2012.05.02, 01:42 PM
I have been using epoxy putty


What was the difference in RPM's after the armature was balanced?

Team Nissmo
2012.05.02, 06:34 PM
I haven't tested one before and after yet will prob get round to it this weekend.

heres a vid of it in action.

http://www.youtube.com/watch?v=R_Wy7jU-KRk

Team Nissmo
2012.05.03, 12:26 PM
I have completed my first before and after test on a good working motor.

Before balancing = 53k-55KRPM erratic peak @4.8V
After balancing RPM = 60K smooth peak @4.8V

It is a home brew 35T double taken out of my friendís car so we will see what difference it makes on the Tamiya speed checker and track!

The putty I am using seems to gain weight as it hardens??? I have tested 2 motors that both needed some sanded off once once it had set.

egonzalez
2012.05.03, 04:32 PM
I have completed my first before and after test on a good working motor.

Before balancing = 53k-55KRPM erratic peak @4.8V
After balancing RPM = 60K smooth peak @4.8V

It is a home brew 35T double taken out of my friendís car so we will see what difference it makes on the Tamiya speed checker and track!

The putty I am using seems to gain weight as it hardens??? I have tested 2 motors that both needed some sanded off once once it had set.

What would cause the putty to gain weight???? The amount of putty used doesn't change before or after setting. A motor that has little to now vibration will always be faster and transition of power is also smother.(faster spool up)

I-Lap
2012.05.03, 06:44 PM
I have been using epoxy putty

Would it not be better to remove a little metal from the heavy side instead?

The balance would not change after curing and there is also no fear of the putty coming loose and high temp and RPM's.

.

Team Nissmo
2012.05.04, 12:15 PM
Would it not be better to remove a little metal from the heavy side instead?

The balance would not change after curing and there is also no fear of the putty coming loose and high temp and RPM's.

.

I think the metal affects the magnetic field so removing some from one side could make the fields different in strength.

I have balanced a few more and think I was going crazy about the weight gain with the putty on the first 2 as these have stayed the same. I made the silly mistake of balancing it and then before it set moved the putty further out to make it look pretty. I also rubbed it with water after as it makes shiny lol.

"Steel reinforced epoxy putty. Dries steel hard in 15 minutes. Ready to drill, tap, file, machine etc. after one hour. Permanent repairs to metal, glass, plastic, ceramics, wood and more. Bonds like epoxy, hardens like steel.
Sets up under water, impervious to chemicals, 500 degree temperature resistant"


I will balance some magnets next with a gauss meter.

imxlr8ed
2012.05.04, 12:26 PM
I'm guessing that when it cures, it draws in oxygen as part of the hardening process? So it's gaining weight as the bonds begin to form.

Make sense?... I could be completely wrong too! I'm only a helicopter engineer, not a rocket scientist. :rolleyes:

Team Nissmo
2012.05.08, 05:08 PM
I have done a PN 70T but adjusted the timing at the same time as it affects the balance:
Before 20000-22000 RPM
After 25500 RPM

I balanced my home made 35T double (this one is in a PN35T can with neo magnets and had the timing adjusted already)
Before 38-39 KRPM
After 45 KRPM
It gained 5KPH on tamiya speed checker, sounded so much better but the big difference is on the track:D:D:D

HaCo
2012.10.14, 12:55 PM
Thanks for sharing, very interesting reading!

SAGISI
2012.10.15, 08:42 AM
How do you adjust the timing?