2005 FP Pinion [Archive]

Cory

12-01-2005, 13:39

Anyone have an idea of how this gear is attached to the shaft - and any success removing it safely. What methods have been used?
Thanks in Advance
Ken
Team 476
6th year rookie

The best way to do it would be with an arbor press.

You *COULD* attempt to cut a wedge out of it with a dremel and remove it that way. I don't think this is a good method at all, but some teams swear it works. You have to be incredibly careful to make sure that you dont cut into the shaft, or get shavings into the internals of the motor.

Also, I believe Paul posted a drawing for a gear puller that can be made with a mill, on here last year sometime.

Max Lobovsky

12-01-2005, 13:42

How would you press, or pull for that matter, it off? I can't see how you can support the shaft properly.

UCGL_Guy

12-01-2005, 13:50

First let me say we haven't received our kit yet so I haven't seen this year's motors. Our machinist in just quickly looking at some from prior years said they look like they are "glued" to the shafts. has anyone actually removed these gears from the shafts this year?

Keep the cards and letters coming.
KY

Cory

12-01-2005, 13:53

How would you press, or pull for that matter, it off? I can't see how you can support the shaft properly.

Cut a slot in a plate and slide it on the shaft so it's supporting the gear.

UCGL_Guy

12-01-2005, 15:05

thanks for all the help- got an answer from the source.
press it off

MattB703

12-01-2005, 19:57

Dan is correct. Everyone should have a 14 tooth, 32 Diametral Pitch gear on the FP motor. THe documentation on the list of kit parts says 21 teeth and it is wrong.

-Paul

I am confused.

I just counted the teeth on our F-P motor from this year's kit and it has 15 teeth, not 14. :ahh: I counted it 4 times and had 2 other people count it.

Can anybody physically confirm the number of teeth on their motor?

Thanks
Matt B.

Joe Johnson

12-01-2005, 21:23

I am confused.

I just counted the teeth on our F-P motor from this year's kit and it has 15 teeth, not 14. :ahh: I counted it 4 times and had 2 other people count it.

Can anybody physically confirm the number of teeth on their motor?

Thanks
Matt B. 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.

If you have 15T, then F-P has provided and/or FIRST shipped a mixed lot. Without actually taking the motor of the transmission it is close to impossible to tell the difference. Even off the transmission it can be very hard to make the ID.

Paul Copioli and I can tell you that the folks that service these transmissions for F-P (in the Detroit area in is McNichols Electric just down the block for Beaumont Hospital on 13 Mile) have absolutely no idea which motor is which, in fact, the guy told me he goes SOLELY by the # of teeth on the motor pinion when he sells a motor. Paul and I both told him that this is not really an adequate method, but I don't think we made a dent.

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.

How many other teams have counted the pinion teeth carefully? Any more 15's out there?

Joe J.

Tristan Lall

12-01-2005, 21:46

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.

If you have 15T, then F-P has provided and/or FIRST shipped a mixed lot. Without actually taking the motor of the transmission it is close to impossible to tell the difference. Even off the transmission it can be very hard to make the ID.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

Biff

12-01-2005, 22:11

Anyone have an idea of how this gear is attached to the shaft - and any success removing it safely. What methods have been used?
Thanks in Advance
Ken
Team 476
6th year rookie

We had good luck last year on the hardened gears on the drill motors with a cold chisel a block of steel and a ball peen hammer. I would test this on a softer gear for a motor that you are not going to use or a spare. I just put the chisel (a small one, that didn't fit to the bottom between the teeth,and not too wide) between two teeth with a helper holding the motor and the block of steel under the gear, and gave it a good whack. It split the gear almost down the center and the remainder came off with a gentle tug with fingers. I don't know if this is an excepted method, but it did more for us.

MattB703

13-01-2005, 10:12

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. :confused: The part number on the motor is 74550-0642.

Matt B

UCGL_Guy

13-01-2005, 10:16

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

Joe Johnson

13-01-2005, 11:05

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

13-01-2005, 11:55

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 #.

Mike Betts

13-01-2005, 15:11

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?

Mike Betts

13-01-2005, 15:39

...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

13-01-2005, 17:57

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.

MattB703

13-01-2005, 21:44

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. :confused: 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. :mad: Makes it kinda tough to use them as a set.

Peter Matteson

13-01-2005, 22:03

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.

Andy Brockway

14-01-2005, 07:15

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?

Paul Copioli

14-01-2005, 08:01

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

14-01-2005, 09:14

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

14-01-2005, 09:29

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

14-01-2005, 09:35

I will further muddy the water and point out that Guidelines_C.pdf give a stall current of 148A for the motor alone and 70.3 A for the motor/gearbox assembly (which is how I measured stall).

While I admit I may not be the sharpest pencil on the desk, how could the gearbox affect the stall current measurement?

Paul Copioli

14-01-2005, 09:41

The gearbox specs in the guidelines is wrong. The motor specs are the only items I verified with Mabuchi.

Max Lobovsky

14-01-2005, 09:45

We've got another pair of

74550-0642
TD034701
13 tooth pinion
Haven't measured resistance.

We really need to get this cleared up soon because we've all got to buy some gears and sprockets and we need the correct torque/power/speed data...

Joe Ross

14-01-2005, 09:46

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?

Joe P

14-01-2005, 10:16

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

Joe Johnson

14-01-2005, 10:45

Dr. Joe, did you measure it already, or is this a calculated value?
I will try to get to this over the weekend. Sadly, the power supply I need to do this is back here at Delphi and the parts are in Pontiac (about 1/2 hour away).

Joe J.

Biff

16-01-2005, 13:50

I will try to get to this over the weekend. Sadly, the power supply I need to do this is back here at Delphi and the parts are in Pontiac (about 1/2 hour away).

Joe J.
Checked ours, 13 teeth
Read the Friday Email about the Typo in the kit for the FP's. I also had the kids measure the free speed with the transmission. 144 rpm, battery fully charged, fuse, no victor. which is no surprise as last years was 130 same conditions.
Cheers
Tom Cooper
1227

DGiandomenico

18-01-2005, 13:51

Here are a couple measurements on our 2005 Fisher Price Motor

13 teeth; 1/2" O.D. pinion

Part ID# 74550-0642
Code: TD034701

Measured RPM*:
24,500 @ ~12V (voltage approx)
12,000RPM @ 6.0V
-11,600RPM @ -6.0V (reverse direction)
* Measured using R/C airplane hobby tach & transparent disc w/stripe

Motor Resistance**:
0.069 - 0.074 ohms

**Measured with 10A current source; 4 point measurement of 0.69-0.74 V while turning rotor between fingers

Calculated stall current from above:
162 - 173A (12V/0.069ohms; 12V/0.074ohms)

All these measurements agree well enough by those provided by Paul Copiola at

http://www.chiefdelphi.com/forums/showthread.php?t=32442

-David

MattB703

22-01-2005, 19:10

To take this question to the next level;

Does anyone know or want to hazard a gues as to what the pressure angle is on the gears used in the FP transmission?

Matt B

Tristan Lall

23-01-2005, 13:09

Does anyone know or want to hazard a gues as to what the pressure angle is on the gears used in the FP transmission?20° (at least, that's what the old ones were). The new gears look like they have the characteristic "sharp" teeth, so short of taking measurements, I'd definitely say that that's what they are.

Joe Johnson

23-01-2005, 13:25

20° (at least, that's what the old ones were). The new gears look like they have the characteristic "sharp" teeth, so short of taking measurements, I'd definitely say that that's what they are.
From history, I'd say you are pretty safe in saying it is a 20 Degree Pressure angle.

They typically use standard DP and pretty standard gears (no enlargements or thickening of teeth, etc.).

Joe J.