Fisher Price Motor .. Important!

[Paul Copioli]

I have just verified with an engineer from Mabuchi Motors. The motor we received in the kit is NOT the same as last year. It is NOT a Johnson Electric motor. The part number displayed on our kit motor (on a sticker) is 74440-0640. The Mabuchi part number that corresponds to that motor is RS-550PF-6534. I will have Brandon attach the spreadsheet, because it is too big for me to do. Key information is:

Stall T = .382N-m
Free speed = 15,000 RPM
Free Amps = 1.1
Stall amps = 57

I am still working on the others,

Paul

[Brandon Martus]

http://www.chiefdelphi.com/forums/papers.php?s=&action=single&paperid=136

[Bill Gold]

Thanks for the info Paul.

[kmcclary]

Originally posted by Paul Copioli
I have just verified with an engineer from Mabuchi Motors. The motor we received in the kit is NOT the same as last year. [...] The key information is:

Stall T = .382N-m
Free speed = 15,000 RPM
Free Amps = 1.1
Stall amps = 57

I am still working on the others,

Paul Wow! GREAT catch, Paul!

...And THANK YOU for sharing that! (Talk about Gracious Professionalism!) :D

That note may have just saved the bacon on a LOT of teams! That's a 25% lower free speed than the old FP/Johnson. I can envision a BUNCH of teams scratching their heads in weeks 3-6 wondering "what the heck did I do wrong with my calculations ??", when it didn't "rev up to spec".

Major props for Paul...

NOW I'm VERY curious about the OTHER "big boy" motors! :) When you find/determine the other motors' specs, can you please post the links to their data sheets too?

Thanks again!

- Keith

[Jon Lawton]

Does anyone have information on the Fisher Price motor pinion?

I took mine out today and much to my surprise it has 19 teeth, and each tooth looks a bit "fatter" than the ones we got in 2001, so I assume it is less than 32 DP. I do not have a good way to measure the DP and Pressure Angle... I should get some tools to do so at some point.

[Paul Copioli]

The Fisher-Price is still 32DP, but it is 19 teeth. I just measured several of the "over pin" dimensions as well as mated it up to some other 32 DP gears.

-Paul

[Simon G]

Paul, or others,
Do you know what the pressure angle of the stock FP pinon gear is? Is it 20 deg or 14.5?
Thanks!
Simon

[Paul Copioli]

20 degree pressure angle.

-Paul