Gear rotations when slowing/stationary

[atxrcguy]

This is a little hard to describe and I might need to post a video...

Even though I've had my RC10T4 for some time, I'm still new to RC. I pulled this truck out of the box and got it up and running again. I just purchased a Havoc Spec 17.5 sensored brushless system.

I'm having a weird problem that suddenly seemed to occur. When my truck slows down right before it stops, or I drive in slow speeds, it seems to "jitter" a little. It's not the ESC because it does the same thing when the power is shut off and I push it along the floor. I noticed the "jittering" is the motor will still turn a time or two along the spur when things are slow or stationary. It's hard to describe, I can post a video if needed.

Thanks for any feedback. Appreciate any help/advice.

[jwscab]

electric motors will have a very 'clunky' feeling when spinning them by hand, because of the magnets inside. they'll have an initial soft turn-in then become much harder, then kind of roll-over the magnetic field and spin quickly into the next 'zone'. the magnets repel the iron in the cores, so they want to get as far away as possible from one another. so when you are turning and you feel the 'hardest' position, that's when the same poles are lined up, positive to positive, or negative to negative and have the most repulsion to each other.

the way motors work to spin is that the magnetic field gets pulsed round-robin which pushes(or pulls) the core away, and because of the construction, the only way to go is around to the next field, etc etc etc.

here is a really neat animation with lots of information:

http://www.townbiz.com/animations/2-pole_bldc.html

if that's the effect you are describing, then that's what it is. If I misunderstood your question, just add some more detail.

[atxrcguy]

Thanks for the reply.

Here's a video of what I'm talking about. I'm not sure if this is normal, or if it's because the pinion is not close enough to the spur... There's about a paper-width in between them. Notice how it easily moves when the car is stationary, then the noise it makes when I roll it.

[youtube]tZtuA5KxWPE[/youtube]

It seems to me like it turns too much. Once the truck is going, there's no loud "clanking" or jittering noise.

[adam lancia]

Your gear mesh doesn't sound all that good but the notchiness you are seeing is from the magnets in the motor.

[SRTracer121]

Your gear mesh doesn't sound all that good but the notchiness you are seeing is from the magnets in the motor.

+1