Big Black Motors

[Kit Gerhart]

Is there any torque/rpm/current draw data on the new big black motors? There didn't seem to be anything about them in our initial package of info. Also, does anyone know the normal use of these motors?

[ggoldman]

There is information on the motors on page G-25, they are easily confused with the bosch drill motor, so watch out.

[TF8]

that info is for the little mabuchi not the big chuachi or what ever its called

tyler forbes

[Joe Johnson]

They are made by Chiaphua. They are used in Atwood Mobile Power Jacks. All models of power jacks use the same motor and the same gear cluster mating with the motor (the very one in the kit -- thanks to Atwood -- this makes a very nice addition to the kit just a bit easier to use). The jacks are available at most RV centers, in stock. Cost is $150-200 or so based on the model and the markup of the dealer.

Atwood Mobile Power Jack (http://atwoodmobile.com/Products/chassis/powerjack.cfm)

http://atwoodmobile.com/Images/whats_new/PowerJack.jpg

Specs should be out soon but as I recall, the numbers are 2.2N-m stall torque. 107Amp stall current, 5500RPM free speed, ~2 Amps free current (all @ 12V).

The output gear is VERY non-standard. It is a 36 Diametral Pitch, 9 tooth, enlarged, 25 degree pressure angle gear. Actual data should be out soon.

The gear that mate with it is a 44T gear (4.888:1 ratio). The center distance will have to be slightly enlarged from nominal I think, though I am not sure of the exact value -- it should not be too fussy. The smaller gear clustered with this gear is a standard 32 D.P. gear

By the way, it was touch and go getting these beauties in the kit. I have been working with Chiaphua for months to get these babies in the kit, it almost didn't happen. In the end, Chiaphua gave us a good price, I BEGGED my management for some funding to cover most of the price and then I BEGGED FIRST to kick in the balance of the funds to seal the deal.

I am very happy that we ended up getting these in the kit. I hope that they work out well for all teams.

Joe J.

[Andy Baker]

Joe,

This motor is drop dead gorgeous!

Thanks for your efforts. Teams will definitely appreciate this new "big kid on the block". Now... back to the drawing board.

Andy B.

[Kit Gerhart]

Thanks for the tech info, and for your effort in getting these motors in the kit. I suspect that there will be some 'mean machines' this year. It looks like we have a lot of available horsepower for our robots. Those 60A breakers may be more of a problem than in the past, though. Does Small Parts sell dry ice?

[Paul Copioli]

Thanks Joe for the info.

I came in to work today, just to check the forum, because I knew you would have the info.

For our team's sanity, we are calling the motor the "Chalupa".
(Chicken Chalupa)

-Paul

[Joe Johnson]

The company pronounces their name l"Chip-ee-wah" (like the Native American tribe) at least in English speaking countries.

The company has engineering in Toronto (among other places)and manufacturing in China. I suspect that the name sounds more like "Chee-a Poo-a" in Chinese (neglecting the all important tones that are an integral part of the language).

One more thing that folks should know about heat and motors and scaling of sizes:

Roughly speaking, the heat dissipation rate (heat power) is proportional to the area times the delta in temperature.

If you double the size of the motor, you quadruple the surface area of the motor. So... If you have the same about of heat generated per second inside your motor windings but the motor is twice as large, you will only generate 1/4 the delta in temperature that the smaller motor would generate.

Note, to first order, the drill motors and the Chiaphua motors are the same power ratings, given approprate gearing, they will do the same job in the same time generating the same electrical losses (i.e. heat).

Bottom line: If your drill motors were hot enough to boil spit (the true measure of all hot things by the way), the Chiaphua motors (geared appropriately) will only be warm to the touch*.
Think Cool Thoughts...

Joe J.

*for the purposes of the explanation boiling spit was taken to be 212 degrees F and room temp was taken to be 75 degrees F. In this case, "warm to the touch" works out to be about 110 degrees F (75 + (212-75)/4) Very nice indeed...

[Tom Fairchild]

We really appreciate the info on the motors, Joe. Any idea if you can get us a curve for it?

~Tom Fairchild~, who's loving these things.

[Marc P.]

I like these big suckers, but how many are we supposed to have in the kit, and how many are we allowed to use? I think the list of parts for the kit says 1, but when we opened our kit we found 2. Is this allowed or is it a mistake?

[Katie Reynolds]

Originally Posted by Marc P:
I like these big suckers, but how many are we supposed to have in the kit, and how many are we allowed to use? I think the list of parts for the kit says 1, but when we opened our kit we found 2. Is this allowed or is it a mistake?

If you look at the Kit of Parts checklist it says that 2 Chiphua motors should be included. But there is also other documentation that says we should only recieve one. I asked one of my advisors that was at the Kokomo kick off and he said that it was said that we should all be recieving two Chiphua motors so I am guessing that this is perfectly legal. I believe that everyone got two Chiphua motors in their kit so... I hope this helps!

- Katie

[Kit Gerhart]

[i]

If you double the size of the motor, you quadruple the surface area of the motor. So... If you have the same about of heat generated per second inside your motor windings but the motor is twice as large, you will only generate 1/4 the delta in temperature that the smaller motor would generate.

[/B]

Doesn't this assume that temperature rise is only a function of the thermal mass of the motor and that cooling is only a function of 'radiation' from the outside of the motor? This is probably a good model for what might happen with drive train motors in a two minute match, but for lighter loads, when allowed to 'spin,' the drill motors can have a fairly low equilibrium temperature because of the cooling from the little fans that pull air over the armature and commutator. We can run our robot indefinitely in low gear without the motors getting very hot. Of course, when running for a long time in high gear, more heat is generated and the fans don't move as much air, so occasionally the smoke leaks out of the motors.

[Anton Abaya]

these are motors? i thought they were pencil sharpeners.

-antoninny

[Joe Johnson]

As to Temperature effects...

Thermal mass helps the things stay cool in the short run but not in the long run because eventually the mass is the temp of the windings.

My first order analysis does not take the airflow into account which can be a big effect (as you will find out if your motor mounting design blocks the holes on the drill motor -- they run MUCH hotter with the holes blocked.

But, my basic point is still valid. Doubling the motor size more than halves the temperature rise inside a motor for a given amount of heat per second generated by the I^2R losses of the motor windings.

As to speed torque curves...
Download the FIRST MOTOR CALC spreadsheet from the whitepapers section of this website and you can plot them yourself -- all the data you need is the 4 numbers I gave you.

Joe J.

[ggoldman]

Joe....


The motors in question....(big Black ones)....

A couple questions about them

1) What is their function in the real world...do they turn a lead screw which in turn jacks up RV's or what not?
2) Are the mainly speed or torque?


Also, we have read the manual over and over again but have not found any rule limiting the quantity of motors allowed on the robot. I know this doesnt sound right. Can you straighten this out for me

THanks

Gabe G.

[Dan 550]

These new motors are definitely some that I will not just hook a battery up directly to get a torque and vibration feel. Thank you so much for getting these in the kit, Joe. You are indeed a saint.

Oh, are we allowed to use the motors from previous years not included in the 2002 kit? I'm unclear on that point.

[P.J. Baker]

There are no motors on the additional hardware list, so we can only use the ones that came with the kit.

P.J.

[Joe Johnson]

The motors are used to drive a gearbox, the output of which turns a nut which makes a screw go up or down.

As to whether these motors are mainly torque or speed, of course, they are both. These motors are powerful. That means that the product of speed and torque is a high number (peaking at about 300W). Compared to many motors these motors are fast and not very torquey compared to many others they are slow and torquey.

For a FIRST motor they are about as torquey as an armature gets without a gear reduction.

I think we will grow to love them.

Joe J.

[Alan Ing]

Hi All,

We decided to have our kit shipped to us this year and since we are in Hawaii, 2nd day air usually takes an extra day or two.

The new motor sounds really great. Could someone who has received their kit please describe to me the gear that they included to mate to this motor? I believe Joe mentioned that the motor itself had 9 teeth and that the mating gear had 44 teeth. From what I understand, this 44 tooth gear also has a 32 DP gear attached to it. How many teeth does that gear have?

Also, what's the diameter of the motor shaft? Does anyone think its reasonable to pull the 9 tooth pinion gear off of the motor and replace it with something more common?

I'm starting to regret that we didn't pick up our kit at the remote kickoff!

[Marc P.]

I Believe the mating gear is 44 tooth, 36 DP, with an attathed 16 tooth, 32 DP probably with a 20 deg. pressure angle gear.

Hope this helps.

[Marc P.]

Originally posted by Marc P.
with an attathed 16 tooth


Attatched, yes I can spell at 6 am.

[Kit Gerhart]

The gear appears to be made of some type of bronze. It is a gear 'cluster' with the 44 tooth and 16 tooth gears next to each other, and has a 1/4 inch hole through it.

[Alan Ing]

Marc and Kit,

Thanks for your reply! At least our team can start thinking how we might use the new motors!

Alan

[Andrew Dahl]

does anyone have the scematics for the chipewa motor
I am mostly looking for the radius for the center of the gear
out


thanks

dahl
home of the chalupa

[Paul Copioli]

I sent several file formats of the Chiaphua motor solid model to Ed Sparks. After he reviews it, he will most likely post it on his web page. I created it in SolidWorks, but saved to several other formats.


-Paul

[Dan 550]

Boy, we were having a heck of a time trying to determine what the brass double-gears in our bearing bag were for. That sure clears that up. Now if they had put them with the Chiphwa motors, where they belong, it would have been clear. It's all so clear now that the brainfog has been lifted...

[DougHogg]

Hi,

As a part of rookie team, those new black motors certainly have appeal but I have no idea how to implement a drive train with them.

Is there anyone out there who can give us an idea of how to use them for a two-wheel drive high torque configuration for pulling goals?