question

[Jason O'Connell]

I have a compass 4926 motor that I had in my 7hv. I was using it with a Scorpion 130a ESC and had shutdowns on my 5th and 6th flight. I crashed after the second shutdown.
During teardown and inspection I noticed while spinning the motor by hand that all the "cogs" do not feel the same. Some of the magnetec poles seem to grab and advance the motor verry hard and hold it there hard as well. But some of the poles feel much weaker and do not seem to grab or hold the motor in place nearly as hard.

Is this normal or do I have a problem here?

Any advice would be apreciated!

Jason

[Stolla]

its not normal, should be same all round, take it apart and check it out, already a lot of issues with these motors it seems

[powercroco]

as far as I know from one of my motorbuilding friends, the quality of the one, he wanted to rebuild was extremly ugly - he gave up!
what he found was far,far away from quality of the 4530 I have rebuilt.
it makes no sense, if you have to break out all magnets and reglue them in correct distances and restack the plates in correct direction!
so its easier to built a complete new motor.....

unfortunally he don't want to see the photos in internet.

may be, someone can open one and take some photos?

[Jason O'Connell]

I have the motor apart and nothing looks wrong to me. all the magnets seem to be in place and none are loose. all the windings look ok.

What would cause this and could it have been the cause of my shutdowns? I was not pushing the heli hard at all and can not believe I should have been pulling enough amps to shutdown a 130amp esc.

[powercroco]

photos?

and pls. measure the distances between the magnets.
they must be equal by about 1/10mm.

[Jason O'Connell]

I measured the distance between the magnets in the can and they all are within .005 inches.

I also noticed some places on the windings where the coating is flaking off.

Here are the pics Ralph. Sorry they are not better.


Jason

[powercroco]

looks much better than expected.
so there is no chance to say from far, what is the reason for your problems.

winding looks not so good....
can you check it for shorts (1000V) ?

[_Dekker]

Did you test the Scorpion esc on other motors before running it on the Compass motor?
My experience with this esc has not been good at all...

[apostolosnt]

Barnstormer I have noticed the same thing on mine. While spinning it by hand slowly every 4th and 5th "step" is noticeably weaker than the rest. And it is specific to every 4th and 5th. Not consistently strong magnets?
Maybe this tells something to those more knowledgeable.
As far as I can inspect same story: Nothing is measurably wrong.
The winding looks much better though.
As I posted on the 7HV forum it gets too hot with no load, just free spinning motor, (49*C in 1 min) so I assume something is wrong.

[Jason O'Connell]

Originally Posted by _Dekker

Did you test the Scorpion esc on other motors before running it on the Compass motor?
My experience with this esc has not been good at all...

First use of the Scorpion ESC was with the compass 4926. I had no other 700 size motor to test with.

[Jason O'Connell]

Originally Posted by powercroco

winding looks not so good....
can you check it for shorts (1000V) ?

I have no way to do so. I wish I did.