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Author Topic: Epic 12t help  (Read 3369 times)

Fausto_De_Rossi

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Epic 12t help
« on: June 25, 2013, 04:11:53 AM »
I know this is probably a very lame question for most of you, but forgive me cause I am such a noob.

Short story is my motor quit working. I'm pretty sure its because I'm running a brushed motor with lipos. I was expecting a failure at some point.

My question is, is this motor salvagable?

PIX:

One brush is obviously wearing more than the other one


The commutator is oval, and obviously needs to be polished. Oval seems like bad news - can it be brought back to round? AND is it normal for the armature to appear 'askew' as it does"


The motor has an onboard circuit? What is this?


And this is how it was wired to the ESC. Red and blue to ESC, with the red "teed" to batt. Is this normal?


ANY help to this nood would be greatly appreciated! I would eventually like to go brushless but can't afford to to for a while, so I'll have to repair this myself. THANKS IN ADVANCE!

regards, Oz

« Last Edit: June 25, 2013, 04:13:47 AM by Fausto_De_Rossi »
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Nuova Faor SF509Re; Epic 12T 540, PRO BIKE forks, NF upgraded steering damper, PMT's Medium durometer front and rear, Savox Titanium geared steering servor, Mtroniks CIRRUS ESC, Spektrum DX3R DSM2 transmitter, Spektrum SR3100 2.4Ghz DSM2 Receiver, Thunder Tiger rider who's name is Fausto De Rossi

Adder

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Re: Epic 12t help
« Reply #1 on: June 25, 2013, 09:04:25 AM »
Let's see what you've got:

A burned out brush and a distorted/burned comm.  :( That would suggest it's got massively overheated and looks like the armature is scrap. That's either a gearing issue or the motor has got jammed with the throttle wide open, lipo cells by themselves don't cause a problem :)

For a rebuild you'd be looking at a new armature and brushes at a minimum, it doesn't look as though that comm would skim back to true in a lathe.

For the price of rebuild parts, you can get perfectly good machine wound modified motors for only a few 's/$$'s, they're sold as upgrades for Ready-to-Run cars/buggies that come with 'silver can' industrial 540 motors.

Take a look at something adjustable/rebuildable like this in a 15/16/17 turn wind for a combination of driveability and performance:
 http://www.amainhobbies.com/product_info.php/cPath/1_221_1889_222_2850_2843/products_id/222140/n/Team-EPIC-SpeedGems-Emerald-540-Brushed-Electric-Motor-16x2

The PCB you can see has the radio 'noise' suppression capacitors on it, that's normal, as is the tee wiring, assuming you've got a three-wire output Speedo?

Three wire output speedos use one common output wire with seperate control wires, and it both makes the speedo smaller and reduces (a little!) the current losses by using less wire. The current loss thing is very small and not something you need to bothered about unless you're running the A-main final at the national championships!



Other brushed speedos have four wires, two for the battery and two for the motor, but they're simply connected into three poles inside the case just to make them easier to plug-and-play.

To avoid the issue again, check out the gearing on the bike for your regular running area. More teeth on the pinion will make it higher and give you more top speed, at the expense of run-time, lack of acceleration and a hotter motor. Fewer teeth on the pinion will give you less top speed, but much more acceleration and torque with a cooler motor.

The trick is to get gearing that will allow the bike to rev up to full speed in about 2/3 - 3/4 of your longest straight, but still pull out of the corners without labouring/struggling. You'll get away with higher gearing on a parking lot where it's wide open, but will need lower gearing on a tight and twisty track.

For good life and reliability, the motor should ideally not get any warmer than hand-hot to touch (~40-50*C, 100-120*F) if it's geared correctly and all the drivetrain is free-running.

HTH
« Last Edit: June 25, 2013, 02:32:30 PM by Adder »
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Scott Adderson
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Fausto_De_Rossi

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Re: Epic 12t help
« Reply #2 on: June 25, 2013, 02:38:48 PM »
You are truly AWESOME! Extremely valuable info - I thank you sir

Let's see what you've got:

A burned out brush and a distorted/burned comm.  :( That would suggest it's got massively overheated and looks like the armature is scrap. That's either a gearing issue or the motor has got jammed with the throttle wide open, lipo cells by themselves don't cause a problem :)

For a rebuild you'd be looking at a new armature and brushes at a minimum, it doesn't look as though that comm would skim back to true in a lathe.

For the price of rebuild parts, you can get perfectly good machine wound modified motors for only a few 's/$$'s, they're sold as upgrades for Ready-to-Run cars/buggies that come with 'silver can' industrial 540 motors.

Take a look at something adjustable/rebuildable like this in a 15/16/17 turn wind for a combination of driveability and performance:
 http://www.amainhobbies.com/product_info.php/cPath/1_221_1889_222_2850_2843/products_id/222140/n/Team-EPIC-SpeedGems-Emerald-540-Brushed-Electric-Motor-16x2

The PCB you can see has the radio 'noise' suppression capacitors on it, that's normal, as is the tee wiring, assuming you've got a three-wire output Speedo?

Three wire output speedos use one common output wire with seperate control wires, and it both makes the speedo smaller and reduces (a little!) the current losses by using less wire. The current loss thing is very small and not something you need to bothered about unless you're running the A-main final at the national championships!



Other brushed speedos have four wires, two for the battery and two for the motor, but they're simply connected into three poles inside the case just to make them easier to plug-and-play.

To avoid the issue again, check out the gearing on the bike for your regular running area. More teeth on the pinion will make it higher and give you more top speed, at the expense of run-time, lack of acceleration and a hotter motor. Fewer teeth on the pinion will give you less top speed, but much more acceleration and torque with a cooler motor.

The trick is to get gearing that will allow the bike to rev up to full speed in about 2/3 - 3/4 of your longest straight, but still pull out of the corners without labouring/struggling. You'll get away with higher gearing on a parking lot where it's wide open, but will need lower gearing on a tight and twisty track.

For good life and reliability, the motor should ideally not get any warmer than hand-hot to touch (~40-50*C, 100-120*F) if it's geared correctly and all the drivetrain is free-running.

HTH
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Nuova Faor SF509Re; Epic 12T 540, PRO BIKE forks, NF upgraded steering damper, PMT's Medium durometer front and rear, Savox Titanium geared steering servor, Mtroniks CIRRUS ESC, Spektrum DX3R DSM2 transmitter, Spektrum SR3100 2.4Ghz DSM2 Receiver, Thunder Tiger rider who's name is Fausto De Rossi