AM Fisher Price planetary problem

[George C]

Anyone had any problems with the AndyMark Fisher Price planetary gearmotors seizing? We've had two go within the first few minutes of use. Both had grease but one of the planetary gears seized to its pin in each gear motor.

[JesseK]

When I first put the gearbox and FP together a few years ago, I spun the output shaft with my fingers to double check that things were together properly. It turns out that I didn't have one of the 3 bolts fully tightened, by roughly 1/4-turn. After I took it apart for inspection, re-assembled, and tightened it down again things spun smoothly. We used Loctite after that.

Given that the teeth are 32DP (i.e. very small), there's very little room for misalignment. Double check that things are still tight. Also double check that there aren't any imperfections (chips, dings, dents, etc) on the gear teeth themselves, as that would also cause seizing (maybe the motor with attached pinion gear moved around in a loose box in the car on the way home from kickoff? It's happened to us).

[George C]

One of the five planet gears is seized to its pin. The rest spin freely. We bought these assembled as gearmotors and everything was tight. We did get the seized pinion off its pin in one of them but mangled it doing so - it was really seized. The gearmotor spins freely with the 4 remaining planets in place but we don't really want to run it that way under load.

[ChrisH]

Contact AndyMark. They want to know about any deficiencies in their products and will come up with a reasonable resolution.

[T Wallas Pog]

One of our gears froze up. After we fixed it it just froze up again but only when a large load was applied to it.

[waialua359]

Is it freezing or stalling?

[iambujo]

We ordered 2 and got them in on Wednesday. We saw yesterday that one of them felt like it locked up at one spot each rev, we spun it by hand first and caught this. We called AM, and Andy called us right back (! ). He recommended we put it in a vice, spin it with a drill for a few minutes to see if there was a burr that would clean up from the break in.

Note - we first pulled off the motor to ensure there was no visible problem like a loose piece of metal, broken tooth, etc.

We did as Andy suggested and it didn't really loosen up. We called back, and AM shipped replacement gears today for us to try out, hopefully that will fix it.

Moral of the story - nothing is perfect - but AM is a phenomenal company!

[Chris is me]

Originally Posted by iambujo

Moral of the story - nothing is perfect - but AM is a phenomenal company!

We can all learn a lot through AM as we go through our FIRST Robotics seasons. Great service can get you anywhere.

[Tom Line]

Another Story about AM that happened this morning. I was looking at aluminum sprockets, and needed to know the hub diameter. It wasn't listed. I called AM. The phone was answered on the second ring, and the lady who answered didn't know the answer. No more than 5 seconds later I was talking to Andy, who checked the prints and told me the dimension. When I refreshed the web page no more than 10 minutes later to check something else, he had added the dimension.

In this day and age of companies who don't know the customer exists (I'm looking at you banebots), AM is nothing short of incredible.

[Mike9966]

We had one with the same problem last year on a 775 and the AM unit. It was found to be a bur on one of the shafts the gears fit on. They replaced it and all was good. Great company!
Mike

[LeadU2Fun]

We had our first motor mounted and running tests with our shooter for a while. I think it got taken off the shooter and mounted again when it seized. The second one did the same. We were able to punch the pin out the gear was on and replace it with one from the other shaft. Here is a link to our resources site with a summary and picture of the shaft:

(Just click the "login as guest" button)
http://azfirstresources.info/mod/res...iew.php?id=140

[JesseK]

This afternoon, when making an upgrade for an existing conveyor, I tried to stick a 'stock' 9015 from a couple of years ago into one of our three AM Planetaries. It turns out the default gear on the 9015 is a 13T gear, whereas the AM Planetary requires a 15T gear. For planetary gearboxes in general, this difference in diameter makes a big difference. Double check that the pinion on your motor is 15T.

[LeadU2Fun]

When we purchased the planetary gearbox it came with the proper gear. It is a heck of a time to get the old one off, however. Some people are using nut breakers. We used one of the dremel multi-max tools. It oscillates back and forth a fine amount to cut through the gear evenly. Before you hit the shaft you have to use something to wedge it, hit it, and break it. After that, some type of a press is needed to put the new one on. Make sure you support the shaft on the bottom or the motor innards will push out the back.

[sanddrag]

Years ago I had AM planetaries bind after assembly due to excessive slop in the backplate holes for the bolts that join the backplate to the housing. Since having been totally redesigned, I'm assuming this issue has been resolved with a slight locating "boss" or something?

In general, for any gearbox in an FRC application, if I was experiencing binding due to small burrs, slightly close gear fitment, or other "light" (non-serious-flaw) issues, I would go to the auto parts store, purchase a bottle of Rubbing Compound, squirt in a judicious amount, and run it until I watched current draw fall. (I have done this by the way and it works). Then clean it out and grease it up! Just try to keep the compound out of bearings.

[MichaelBick]

We had one of our planetaries seize. They were really old though, and we had chain on the drive axle, that had a really bad tensioning problem. Replaced the gearbox, and had no problems.