Brushed motor questions.

BCbud · November 30, 2009, 11:51:24 PM

Good day!

I have been told that a silver can is an rpm motor and a tan can is a torque motor. My question is what is the difference between them? The reason I am asking is from 2 damaged motors I took a tan can, an armature and end cap from a silver can, and put them together. I am wondering what I have made?

Thanks Neil.

Tom · December 01, 2009, 12:55:19 AM

Technically, an illegal motor, but nobody will care.

Frankly, only the guys running in the A and B would notice much of a difference. The biggest differences are in the armatures, so you'll basically have a silver RPM motor that looks like a torque motor.

BCbud · December 01, 2009, 01:25:49 PM

Thanks for the reply. The only reason I did this is I had one motor with a burnt armature and one with the mounting threads stripped in the can so I made 1 good motor out of 2 damaged motors.

This leads to my next question, are the motor mounting fasteners metric or standard thread? I have been using standard thread.

Thanks Neil.

Tom · December 01, 2009, 05:06:07 PM

I've noticed quite a few racers this year using #4-40 screws to hold their motors in.

It's actually a 3mm thread, or M3x0.5 screw. The length will vary according to the thickness of your motor mounting plate. So, yes, motor mounting fastners should be metric.

RC51 · December 01, 2009, 05:44:31 PM

Quote from: BCbud on November 30, 2009, 11:51:24 PM
Good day!

I have been told that a silver can is an rpm motor and a tan can is a torque motor. My question is what is the difference between them? The reason I am asking is from 2 damaged motors I took a tan can, an armature and end cap from a silver can, and put them together. I am wondering what I have made?

Thanks Neil.

Hey, Neil.

The tan can (or champagne color) is actually the highest RPM of them all but lower torque values than the silver can (monster stock based. The stacks on the arm are different and you should just make sure that when you assembled it, that the arm sits in the centre of the magnetic field or as close to it as you can.

Phil

BCbud · December 02, 2009, 11:44:56 PM

Well, I got some 3mm fasteners and what a difference that makes! With the combination of using the #4-40 fasteners and having a bad surface on my bulkhead, I was needing to tighten them to the point of stripping trying to stop the motor from moving and damaging the spur gear. I took my calipers and did some measurements of the 2 fasteners. I did all the measurements in mm to keep everything relevant. The 4-40 measured 2.82 mm on the threads and the head diameter is 4.58 mm. The 3 mm fastener measures 2.96 mm at the threads and the head diameter is 5.57 mm. So the 3 mm has not only a larger thread size but also a larger head size which will have more contact aria with the bulkhead. I put the 3 mm fastener in the can that I stripped with the 4-40 fastener and they hold just fine!

I hope this helps out some of the new drivers so thy do not have the same problems I did.

Keep the rubber side down, Neil.

WhoDoYouThink · December 03, 2009, 12:41:55 AM

Neil,

It also never hurts to use a washer under the heads of the 3mm motor securing screws. That way, it distributes the load across a larger area and helps secure the motor a little better. Plus, it helps when you have a Gen X or XL because of the top plate being separate from the top of the aluminum motor mount.

Regards,
Nick

BCbud · December 03, 2009, 12:48:15 AM

I am using a washer and lock washer, thanks for the input though!

Tom · December 03, 2009, 01:59:51 AM

Lock washers aren't necessary. Just a M3 screw the correct length, and a plain washer. Without the washer (for others that may be reading this), you'll end up marring the motor mounting plate which will make it difficult to adjust the gear mesh properly when adjusting gears to compensate for tire wear.