New Fisher Price Motor - IMPORTANT

[Paul Copioli]

O.K. everyone, I did a lot of researching on the new Fisher Price motor. 1st, the Mabuchi motor provided in the kit is LAST YEAR's Fisher Price motor, but Fisher Price has gone to a new supplier. The new supplier is Johnson Electric and those are the motors in our kit. They also supply the little 40 Watt motor. There are 3 numbers on the new FP motors: 64715 is Johnson's part number, 00801-0673 is FP's part number, and the 3rd number is a date code. I contacted Johnson Electric North America and talked to a gentleman named Chris Tsui. He e-mailed me the Performance curves for the 64715 motor. Attached is the EXCEL spreadsheet he e-mailed me. In sumary, the motor is roughly 20,000 RPM at free speed and has a stall torque of 0.514 N-m. It has a max mechanical power rating of 273 Watts. Stall current is 105 amps.

I have been talking with the FP service people and it looks like we will have to order these motors via special order. I will keep everyone posted. If anyone can get these motors easier, please let me know. At any rate, team 217 plans on special ordering 20 or so motors (~$20 each), so we will have spares to lend out at the events we attend.

Anyway, here is the spreadsheet.



-Paul

[Ken Leung]

I just looked at the specs, and did some quick calculation... They are not kidding about a max mechanical power rating of 273 Watts.

What a pleasent surprise! The fisher price motors from last year (mabuchi) have a max power of about 140 Watt or so. A 273 Watt is a little less than DOUBLE the power from last year. This is really cool! Just like the johnson motor, the Fisher Price motor's power come from the 20326 RPM of free speed. Now I take back my comment about a drill motor being more powerful than two fisher price...

I wonder why FIRST didn't release specs of this new Fisher Price motor in the beginning. These guys would've made great drive motor along with drills and chiaphuas... unless there are special properties that make them bad drive motors...

Are they really as good as they sound?

[Paul Copioli]

Ken,

I stumbled on this fact after testing our prototype and switching last year's motor and this year's motor. What a difference!! These motors are the reason for some of the gearbox changes that were made.

-Paul

[Joe Johnson]

Thanks for the update!

Question: How many 300W motors can an engineer use?

Answer: As many as you put in the kit!

Joe J.

[Joe Johnson]

I just got a message from a rookie team asking if they should switch from their 2 drill and 2 Chiaphua motor drive system to something that included the New Beefer 2002 Fisher Price Motors.

Below is my reply, for what it is worth...

Joe J.

I wouldn't get too excited about changing directions just yet.

In my opinion, you have the best two motors in the kit for your drive system.

Even at 140 Watts of peak power, it was EASY to toast those babies. It is SO much heat to have to get rid of in such a small package -- that means you need a large rise in temperature to have the heat leave faster -- that means motors that were quite literally smoking. And this was for only 140 Watts. At almost 300 these motors will be very hot indeed.

Beyond this, I think you will be limited by the amount of current the battery can provide to the motors AND by the amount of power you can put to the carpet. Both will be significantly lower than 900 Watts per track.

I wouldn't change your plans at this point.

Joe J.

[Paul Copioli]

Don't go changing any motors around. My post was purely informational. We had to change some gear ratios around because of the new found speed/power. I just wanted to let everyone know what I had discovered. I also think the 2 Chiaphuas and 2 drill motor drive train is the best 4 motor combination.

Joe,

Don't be too sure that a 6 motor drive train will be too much power for the carpet to handle. Time will tell ....

-Paul

[ReijiH]

besides, having too much power isn't too good if the traction doesn't go along with it.