CIM motors

[Or 2230]

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?

[Conor Ryan]

Originally Posted by Or 2230

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?

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!

[Jon Stratis]

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!

[Ether]

Originally Posted by Conor Ryan

The load that is on the shooter will likely be minimal by comparison.

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 ?

[billbo911]

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.

[Ether]

Originally Posted by billbo911

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

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 ?

[billbo911]

Originally Posted by Ether

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 ?

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.

[cgmv123]

Originally Posted by billbo911

The Mini CIM is 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.

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

[Domtech]

Originally Posted by cgmv123

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.

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.

[Jon Stratis]

Originally Posted by cgmv123

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.

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.

[John]

Originally Posted by cgmv123

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.

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

[billbo911]

Originally Posted by cgmv123

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.

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.

[nathan_hui]

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

[billbo911]

Originally Posted by nathan_hui

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

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

[Domtech]

Originally Posted by nathan_hui

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

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