eBay crab pot motors

So it looks like a few people have used these eBay motors recently.
http://m.ebay.com/itm?itemId=370915744975

What is the general consensus? Are they working well for people? The specs look pretty close to the big motors eaorobbie and bsft are using from motion dynamics...just wondering if it's worth the extra (a lot extra!) shipping cost for the motion dynamics ones?

I've had a look at those as well. I was intending to use some wiper motors (which I already have and they're free) at first for a test rig though.
I also spotted these ones as well and was wondering what the differences really are and if these might be suitable for a sim: http://www.ebay.com/itm/GEARMOTOR-1...829?pt=LH_DefaultDomain_0&hash=item5660e6b8fd

Tendonitus has pictures of the insides of the crab pot motors posted in his thread, they are plastic geared but Dave commented that the motion dynamics gearboxes were actually also plastic, an industrial grade. Unless the gear in the crab pot is really low quality I would assume that it would work. I have been tempted to buy two of these myself and try them out.

There are certain grades of plastic which would probably outlast some metal gears but I'm guessing they're not used commonly on motors. I would guess some have PTFE gears would can withstand a lot of abuse. That's why it's used in artificial limbs.

Here's a theory, providing the case was stong enough and the gearing happened to be the weak link would it be of any benefit to have the gears remade in high tensile steel, tooling steel or stainless steel?

As long as it is not cost prohibitive why not? I would guess even stamped steel would work better than low end plastic gears. But would steel be better in a worm gear configuration?

The gear actual looks pretty robust. My thinking was, that pulling crab pots off the ocean floor would be quite a bit of weight and probably more than the sim I'm building. The gear casing appears to be cast aluminum and I also thought about replacing with a metal gear if I do have issues.

that looks fine from the photo. Only one way to test them!
Thats what I did in the beginning, bought and thrashed them.

I have read somewhere on MotionDynamics there Big gear Dayton motor gearboxes are plastic big gear also! But cannot confirm this.

motion dynamics are industrial plastic, not nylon gears. and the motors look like a dayton, but are redesigned internally for better efficiency.
Theres nothing wrong with using ebay motors, they may last, they may not.
Buy some set them up and abuse them!

I am curious, what are the specs on the industrial plastic did they give any?

ask him

I might, but it is not that important to me. I had thought it would be for others who are interested in buying them or those who promote them heavily toward others.

I did notice that their website says that they do not use plastic or bronze gears. From their website: "A budget solution for OEM applications with no plastic or bronze gears used in the construction of the gear motor"

http://www.motiondynamics.com.au/90mm-90-watt-geared-dc-motor-12-24-volt.html


I do wish there were a distributor for these Chinese motors and gearboxes here in the U.S.

This is what we use at the moment.
http://www.motiondynamics.com.au/worm-drive-motor-12v-24v-200w-180-rpm-20nm-torque.html
The PTFE gear inside is stronger than steel, Steel gear will wear out first.
Most cheaper boxes use nylon gearing, ie wipers, rarely some are steel, but really steel to steel gearing can be noisy , winches for example, plus poor alignment of gearing.
On the other hand the Crab pot one's look simular but the big white gear(crown) is different for sure, cross my fingers its the same grade PTFE, then they will be sweet to use.

Thanks Rob, that is what I wanted to know; Polytetrafluoroethylene, also known as Teflon (a brand name by DuPont). I can understand why that would provide a great gear material.

left my JRK at the house, can anyone tell me the dimensions for the heat sink

a T0220 transistor heatsink is a good size

Thanks