Fisher Price Spec?

[Raul]

Has anyone confirmed if this year's FP motors are the 15,000 or 20,000 RPM version?

[JVN]

Raul,
I haven't been able to confirm it.
I believe Paul Copioli is investigating it, and says he should know sometime this week.

http://www.chiefdelphi.com/forums/showthread.php?t=23735&highlight=Johnson+Mabuchi

I'm curious as well... has anyone beat Paul to the verification?

John

[Andy4Hawks]

Okay so I've done some experimentation and a little reverse engineering. It appears that the 2004 Johnson Electric Fisher Price motors have a free speed of about ~10000 RPM. You can check my experimentation (I used a digital dc power supply locked at 12.0 volts) , but the gear box has a ratio of around 124:1 and my counter on the output sline of the trans picked up ~75 rotations per minute. I linearly approximated the free speed based on the current ratios w and w/o the transmission and came out to ~10000.

Our team is very interested in using the FP motor in our drivetrain this year. Since Johnson doesn't put the pinion gear on the motor I'm guessing Paul's spec sheet won't give us any info, does anybody know what the gear type is on the FP motor?

[Paul Copioli]

O.K., here are the specs. I got the information from an engineer at Johnson Electric North America. He will e-mail the spreadsheet later this week, but he gave me the rough numbers so we can get started.

Stall Torque = .64 N-m
Stall Current = 92.8 amps
Free Speed = 15,700 RPM
Free Current = 1.1 amps

So, where does this put us? Here are the specs from last year's Mabuchi Motor and 2002's Johnson Electric Motor:

2003 Mabuchi 2002 JE
Stall Torque = .38 N-m .51 N-m
Stall Current = 57 amps 109 amps
Free Speed = 15,000 RPM 20,326 RPM
Free Current = 1.1 amps 2.7 amps


Comparing Maximum Mechanical Power Output:

2004 JE = 263 Watts
2003 Mabuchi = 150 Watts
2002 JE = 274 Watts

So the bottom line is that even though the free speed is close to the 2003 motor, the output power (which determines speed/torque tradeoff) is very close to the 2002 Johnson electric. The 2002 JE was similar in power to the old drill motors.

Raul,

To answer your question directly, the speed is 15,700 RPM; but you will get similar torque characteristics as '02.

-Paul

[Paul Copioli]

The Fisher-Price gear is a 32 Diametral Pitch gear. The number of teeth differ from year to year and I do not have one in front of me at the moment. To get pitch diameter, take the number of teeth and divide by the pitch diameter. If we had a 16 tooth gear with a 32 DP, then the pitch diameter is 1/2". The pressure angle is 20 degrees (pretty standard).

-Paul

[Raul]

Paul,

From all of the FIRST community, I say thank you so much for the info.

Raul

[Andy4Hawks]

Paul I have to second Raul's comment, thank you very very much!!!

[FotoPlasma]

I too would like to second (third?) Raul's statement. Thank you very much, Paul. You know that you've immediately helped two teams (111 and 258) with your efforts. We all appreciate you.

Keep up the great work.

[Joe Johnson]

Has anyone found the exact part number we need to get from Fisher Price service parts so that we can get the exact motor and/or gearbox from this year's kit?


Joe J.

[Paul Copioli]

Joe,

It is now in the supplier contacts document from FIRST. If you go to a PowerWheels service center and give them the following numbers:

The gearbox part number is 00968-2912
The motor and gearbox are from the folowing products:

1. #75840 Wrangler Restage
2. #B7659 Blue Jeep
3. #C2390 Red Jeep

The 75840 number will be your best bet if the gearbox part number is unfamiliar to the powerwheels distributor.

-Paul

[Joe Johnson]

I just got off the phone with my local Power Wheels service center.

Now I am really confused.

He gave me some run around about they are not allowed (by Fisher Price) to sell electrical parts to the public any more. After much begging and explaining, they agreed to sell me them if I gave them a letter on company letterhead promising not to use them on anything but robots...

...it is a mess.

The reall confusion was only just about to begin. He had different part number for the Jeep #75840. Specifically, the gearbox w/motor he had listed as 00968-2902. He had the gearbox without motor as 00968-2802.

He also claimed that all the motors with the same number of teeth on the pinion are "the same" when pressed he did admit that some where made by Mabuchi and others by Johnson, but "they're the same motor!" I don't believe him! But. this is going to put a curve into anyone trying to get spare parts. If even the serv9ce parts guys have bad information, what are we to do?

Joe J.