2005 FP Pinion

[Mike Betts]

Originally Posted by Tristan Lall

This is worse: 188 has counted teeth, and the number is 13. I've just got off the phone with those involved, and they had separate people count it (twice!). For reference, the identifying marks on the motor are as follows:

74550-0642
TD034701

All,

Team 177 has the number of teeth and markings as Team 188. 13 teeth (and I had two people check it).

Can Dr. Johnson or Mr. Copioli post a (hopefully small) spreadsheet or list of different motors and their relevant specs?

[Andy Brockway]

Originally Posted by Tristan Lall

This is worse: 188 has counted teeth, and the number is 13. I've just got off the phone with those involved, and they had separate people count it (twice!). For reference, the identifying marks on the motor are as follows:

74550-0642
TD034701

I checked our motors last night.

13 tooth
74550-0642
TD014602 - this is different, but what does that mean?

[Joe P]

Originally Posted by Andy Brockway

I checked our motors last night.

13 tooth
74550-0642
TD014602 - this is different, but what does that mean?

Just checked our FP motors.
13 tooth
74550-0642
TD034701
Made in China

Joe P
Team 647 Shoemaker Cyberwolves

[MattB703]

Originally Posted by Joe Johnson

This is bad... ...will you please post a picture of you motor -- especially the sticker on the side, a close up of the gear would be good too.

Joe J.

I have pictures of one of our F-P motors that has a 15 tooth pinnion. I need to check if the other is the same tonight. I'm not sure how to post a picture. The part number on the motor is 74550-0642.


Matt B

[UCGL_Guy]

Ours are 13 tooth - did not check the numbers though -
will look tonight.
Ken

[Joe Johnson]

How would you handle this if you were FIRST?

This is a pretty tricky situation. Do you let teams basically use whatever Fisher Price transmission they want? Do you give teams options (pick from one of these model)?

I swear that I recall a debate in years past between Bill Beatty and I that more or less ran along the line of "my motor has N teeth," "mine has N+1" "F-P sent me replacements with N-1 teeth" and so on.

I didn't know what to make of this then, but perhaps this type of thing has been going on for years.

Anyone have any thoughts on this?

My thought would be that you get what you get as far as what is in the kit for you to use. If you want to go to the bother of getting one of the other parts that other folks got in the kit, feel free to work with F-P dealer/service or trade with another team.

I think this keeps FIRST out of it and it makes it fair if you REALLY need that extra power motor that some other team got.

It will be interesting to see what the variation in performance is on the various motors, but I think for the most part, it won't matter that much. As with so much in FIRST, we will adjust and move on*.

Joe J.


*of course, this is easy for me to say, I have already made the following statement before the House Committee on Unfair Activities: "I am not now, nor have I ever been a member of the Life-Should-Be-Fair Party" ;-)

[Tristan Lall]

Originally Posted by Joe Johnson

It will be interesting to see what the variation in performance is on the various motors, but I think for the most part, it won't matter that much. As with so much in FIRST, we will adjust and move on*.

Are we sure that these are different motors, or could they possibly be the same motor, with a different gear? After all, the spec. sheet (from Mabuchi, not F-P) deals only with the motor characteristics--the pinion itself is apparently reflected in the F-P (and likely not the Mabuchi) part number.

To see if this theory is correct, it would be useful if team members were to post the tooth count of their F-P pinion (i.e. 13, 14, 15, or something else), the F-P model number (e.g. 74550-0642) and the Mabuchi date code (e.g. TD034701) for their motors, so we can see if the proper motors (per Paul's data sheet) can come with different gears, but still under one F-P part #.

[MattB703]

Originally Posted by MattB703

I have pictures of one of our F-P motors that has a 15 tooth pinnion. I need to check if the other is the same tonight. I'm not sure how to post a picture. The part number on the motor is 74550-0642.


Matt B

I just checked the other F-P motor that came in our kit. it has the same part number on the motor and the motor looks the same, but it has a 13 tooth pinnion. So, we have one 15 tooth pinnion and one 13 tooth pinnion. Makes it kinda tough to use them as a set.

[Paul Copioli]

TD014602 - this is different, but what does that mean?

Do not worry about this number. It is the date code used by Mabuchi to indicate when (and where, I think) the motor was manufactured. If you have the same number on the top line, then it is the same motor.

-Paul

[Mike Betts]

Originally Posted by Paul Copioli

Do not worry about this number. It is the date code used by Mabuchi to indicate when (and where, I think) the motor was manufactured. If you have the same number on the top line, then it is the same motor.

-Paul

Paul,

Dr. J measured 10A at 0.8V stall current on his 14T motor.
Team 177 measured 10A at 2.5V stall current on our 13T motor.

While I will admit that we did not measure the voltage right at the motor, I refuse to believe that we dropped 1.7V in the wires and connectors. I would guess more in the 200 to 400 mV range which puts our 12V stall current closer to the 60A indicated for 12V FP motors in the past. Whereas Team 47's motor has a 12V stall current closely matching the 150A specified for the 6V model.

I submit that we have different motors.

Regards,

[Paul Copioli]

Well,

I certainly did confuse the issue. My previous post stated my pinion size was 14 teeth. Well, all the gearboxes I have (two from FIRST that I received to do the study in December) and the two team 217 received in their kit all have 13 tooth pinions.

I can only confirm what the engineers from Mabuchi tell me are facts. One of those facts is that the part number on the sticker that is placed on the motor is the number on the top line. If the number is the same, Mabuchi insists that the motor is the same.

-Paul

[Mike Betts]

Originally Posted by Joe Johnson

...If I were you, I would a stall the motor (for a short period of time) at 0.8 volts or so and accurately measure the voltage accross the motor and the current. If the current is not about 10 Amps at 0.8V (i.e. the Resistance should be 0.08 Ohms per the spec) ,you have confirmation that you have a different motor than the rest of us...

I will measure at 0.8V tonight and report on our 13 tooth version...

[Travis Covington]

Our motors also have 13 tooth pinions. This seems very strange.

It would be if we could gather the specs on all of the motors, regardless of the pinion tooth count, so that it becomes less confusing for us all.

[Peter Matteson]

Originally Posted by Mike Betts

I will measure at 0.8V tonight and report on our 13 tooth version...

Looks like I beat Mike to logging on.

Our results were 10amps at 2.5V. Signifigantly different than Joe's.

[Joe Ross]

Originally Posted by Joe Johnson

If I were you, I would a stall the motor (for a short period of time) at 0.8 volts or so and accurately measure the voltage accross the motor and the current. If the current is not about 10 Amps at 0.8V (i.e. the Resistance should be 0.08 Ohms per the spec) ,you have confirmation that you have a different motor than the rest of us.

Dr. Joe, did you measure it already, or is this a calculated value?