Van Door Motor Disassembly

Is it legal to use van door motors that have been disassembled (ie. remove the worm drive to increase RPMs).
Also, is said endeavor possible.

The only motors and actuators permitted on 2012 FRC Robots include:
A. up to 4 CIM motors (part #FR801-001, M4-R0062-12, AM802-001A, or PMR25R-45F-1003),
B. up to 4, in any combination, of the BaneBots motors provided in the KOP (acceptable part numbers are
M7-RS775-12, M7-RS775-18, M5-RS550-12, M5-RS550-12-B, and M3-RS395-12),
C. up to 2 window motors (acceptable part #s are 262100-3030 and 262100-3040),
D. up to 2 FisherPrice motors (acceptable part #s are 00968-2719, 00801-0673, and 00968-9015),
E. up to 2 AndyMark motors (acceptable part # is am-9012),
F. up to 2 AndyMark gearmotors (acceptable part # is am-9014),
G. up to 2 Denso throttle control motors (acceptable part # AE2351000)
H. up to 2 Vex motors (acceptable part # 276-2177)
I. up to 2 window lift, seat, windshield wiper or door motors obtained through either the FIRST-Automotive
Recyclers Association partnership or from a prior years’ KOP.
J. electrical solenoid actuators, no greater than 1 in. stroke and no greater than 10 watts continuous duty,
K. drive motors or fans that are part of a speed controller or COTS computing device
L. an unlimited number of COTS servos with a maximum power rating of 4W each

(emphasis mine)

This is coming from The Robot part of the Manual. If your motor is on the list, then you’re good to go.


Motors, servos, and electric solenoids used on the Robot shall not be modified in any way, except as follows:
A. The mounting brackets and/or output shaft/interface may be modified to facilitate the physical connection of
the motor to the Robot and actuated part.
B. The electrical input leads may be trimmed to length as necessary.
C. The locking pins on the window motors (PN 262100-3030 and 262100-3040) may be removed.
D. The connector housings on the window motors (PN 262100-3030 and 262100-3040) may be modified to
facilitate lead connections.

(emphasis mine)

If the motors are allowed, then you are allowed to remove the worm gears.

“output shaft interface” typically refers to the external part of the gearbox, where you would mount a sprocket or a driveshaft.

In the past, this rule has been present in basically this exact same form. Every year, removing the window motors has been illegal.

Looking on Q & A, a team has asked about removing the gearboxes from the AndyMark gearboxes. Since this is not one of the listed ways you can legally modify a motor, FIRST directed them to R49. I would expect the same to apply to van door motors.

That said, any answer you get here is not an official answer and cannot be used to prove whether a design is legal or illegal. So you may want to ask Q&A anyway, though you probably don’t want to count on being able to use your design.

Since a van door motor was brought up, is it legal to use the old van door motor that we used to get in the KOP years ago, or do we actually have to go to a recycling center and pull one out of a van?

  • Mr. Van (I know, I know… )
    Coach, Robodox

If it is from a previous year’s KOP, then yes, it is legal.

Note the bold part of the rules. It says, “Prior years KOP”. Reread that section.

That would be modifying an integral gearbox… Read the blue box, first paragraph.

The intent of this rule is to maintain the maximum power level for each Robot, yet still allow teams to modify mounting tabs and the like, not to gain a weight reduction by potentially compromising the structural integrity of any motor. The integral mechanical and electrical system of the motor is not to be modified.

Also note the second paragraph which may shed light for a similar motor class.

Note that for the Window motors and the AndyMark gearmotor, the gearboxes are considered integral to the motor, thus the motor may not be used without the gearbox.

Take this one to the Q&A. The 2012 rules aren’t clear about what’s integral and what’s not. Furthermore, since you can bring in scrap motors never before seen, FIRST can’t decide in advance whether such a modification is legal for a particular design.

Ask FIRST to make a blanket statement about what’s modifiable (under the cited rule) and what’s integral (per the cited blue box), to aid in the selection of motors. They just need to officially say something like “inspectors will operate with a strong presumption that motor gearbox modifications are permissible, unless they have strong evidence that the motor itself has been electrically or mechanically compromised”.

But until that time, it’s hard to answer with any certainty. The worm gear systems have been variously considered integral and non-integral.

Even if it is legal, which it doesn’t look like it is, it would be very difficult to do. I have taken the gearbox off of a van door motor previously to use with a different motor and I had to completely destroy the motor in the process. If I remember right, you would have to cut directly and all the way through the gearbox to salvage the motor.