CIM motors
 

Hello !
My team (2230) is using 6 CIM motors this year:
1 CIM for shooter, 1 CIM for climbing and 4 CIMs for our drive system.
Do you recommend us to split the motors differently?
And what motors does your team use?

Re: CIM motors
 

Watch the gear reduction to make sure you can actually climb effectively. This way you will not overload your motors.

Assuming you do not drive and climb at the same time, you should be in good shape. The load that is on the shooter will likely be minimal by comparison.

I would make the assumption that most teams are using this set up this year. If not I will be very surprised.

Batteries will die faster than usual this year, so make sure you have at least 4 batteries when you go to competition! More batteries = more time to charge!

Re: CIM motors
 

1 CIM motor, properly geared, is perfectly capable of lifting a robot - we did it in BreakAway that way. It wasn't the fastest climb in the world, so we're looking at ways to get some more power into it for this challenge!

Re: CIM motors
 

I would think so.

Maybe you don't need a CIM on the shooter wheel, and you could use 2 on the climber. Has anyone tried one of the lesser motors on the shooter with successful results ?

Re: CIM motors
 

The Mini CIM looks to be close enough to the standard CIM with respect to it's specs. to be used for the shooter. Granted, you will loose some of the rotational inertia provided by the armature. But, a good control algorithm just might overcome that.

---------Free RPM---Stall Torque----Stall Cur---Free Cur-----PWR
Mini CIM---6200--------1.40Nm-------86.0A-----1.50A-----227.24W

We will be testing the Mini CIM in our shooter soon.

Re: CIM motors
 

Smile.

Do you guys have a clamp-on ammeter? Could you measure the current draw for both the CIM and the mini CIM while at the desired wheel speed ?

Re: CIM motors
 

I know you've seen the video's we posted already. Did you see the server rack power supply we were using? Fortunately it has an integrated Vout meter and an Iout meter. I will see if I can get those values this evening. These will be free speed values only. I truly doubt the metering circuit can display the actual current drawn when the Frisbee passes through the shooter.
We have seen the current jump from 3A range to 10A+ and back down with the CIM and a 6in wheel, but I doubt it is accurate.

More data to follow.

Re: CIM motors
 

You have the Mini-CIM and the BAG motor confused. The BAG motor is last on the motor chart. The Mini-CIM is next to last. (The BAG Motor is the bigger of the two.) Don't fret, I mixed up the 2 at first as well.

That said, I like the BAG motor for shooting as well. You're allowed 4, so ganging 2 together comes close or even exceeds the specs of a CIM. Keep CIM's for driving and climbing.

Nevermind

Re: CIM motors
 

According to this page the BAG motor is the smaller one.

EDIT:
Also, the mini CIM is 2/3 power of a CIM at a slightly higher max rpm.
I feel they should work great for shooters.

Re: CIM motors
 

Double check that...
Mini CIM: http://www.vexrobotics.com/vexpro/mo.../217-3371.html
P/N: 217-3371
Size: 2.5” [63.5 mm] diameter, 3.36” [86 mm] long
Specification

Free Speed: 6,200 rpm (+/- 10%)
Free Current: 1.5A
Maximum Power: 230 W
Stall Torque: 12.4 in-lbs [1.4 N-m]
Stall Current: 86A
Mounting Holes: (4) #10-32 tapped holes on a 2" bolt circle

BAG motor: http://www.vexrobotics.com/vexpro/mo.../217-3351.html
P/N: 217-3351
Size: 1.59” [40.4 mm] diameter, 2.72” [69 mm] long
Specification

Free Speed: 14,000 rpm (+/- 10%)
Free Current: 1.8A
Maximum Power: 147 W
Stall Torque: 3.5 in-lbs [0.4 N-m]
Stall Current: 41A
Mounting Holes: (2) M4 tapped holes on a 25mm bolt circle


The Mini-CIM is bigger and more powerful than the BAG motor, although that power comes at higher torque and less free speed.

Re: CIM motors
 

Not according to the VEX website. BAG motor is 217-3351, miniCIM is 217-3371.

Re: CIM motors
 

That may very well be. My source was the "JVN Mechanical Design Calculator". I know this is not an official document. The one you linked is missing any descriptor other than the part number, so it is an easy mistake to make.

Re: CIM motors
 

Maybe we should just call them grandpa CIM, father CIM, and baby CIM.

Re: CIM motors
 

Ah, but don't forget the Great Grandpa "Mini bike motor" CIM from a few years back.

Re: CIM motors
 

Our team has been referring to the BAG motor as the micro-CIM

Re: CIM motors
 

Based on our shooter for last season the motor power does not make a huge difference in shooting distance, it does however affect how quickly you can get the wheel back up to speed.

We initially designed our shooter for Rebound Rumble to be powered by two 775s. One night when we were at our practice location the shooter started making a funny clunking sound. We traced it down to one of the motors. Since we didn't have a spare with us and we were mainly working on our autonomous we removed the second motor. We still shot 95% or so of the distance as we could with two motors, so we stuck with the single motor.

Re: CIM motors
 

I cannot imagine that the smallest CIM, about the size of an RS5550, can be more powerful than the Mini-CIM, about 2/3 the size of the larger 2.5" CIM (and same shaft diameter). Physically they are so very different, the larger one is most likely the more powerful one.

(I wonder where they got the name "BAG Motor" from?)

Re: CIM motors
 

Don't ask.

Re: CIM motors
 

We tried the Mini-CIM on one of our prototype shooters and found that it gave an extra 1-2 meters in range without changing any other parameters, the RPM seems to play a large factor in the range of the shooter

Also we've been calling them mummy/daddy-CIM, teenage CIM and baby CIM.

Re: CIM motors
 

As promised, here is some very raw data. This is a comparison between the CIM and Mini CIM driving the same system.

In a nut shell, the the Mini CIM draws more current at the same voltage.

Re: CIM motors
 

I'm guessing from the manufacturer's name since CIM stands for CCL Industrial Motor co.

Re: CIM motors
 

Using the CIM's current draw (19.4 amps) at 10 volts, the CIM's speed can be estimated.

Re: CIM motors
 

3726 RPM at 10v. Excellent, that confirms that it is operating exactly in the range we expected it would, 2K-4K RPM. It also confirms the video was accurately representing these numbers.

Re: CIM motors
 

Thanks, that's what I am guessing.

Maybe Beijing Autonomous Gearworks or something....:confused:

Re: CIM motors
 

Paul Copioli has some thoughts on this subject. :p

Re: CIM motors
 

i propose

CIM, shorty CIM, and TinyCIM

Re: CIM motors
 

We're using "baby CIM" for the small one because they are so cute:)

Graham.