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logicbomb
10-04-2015, 00:01
FRC Team 271 12cim 2 speed transmissions. Lets play some defence at championships this year (2015).
Whippet
10-04-2015, 00:16
So... do the other 6 CIMS get cheesecake-tethered to another robot to satisfy [R18]?
Kevin Leonard
10-04-2015, 00:50
Please tell me that entire transmission powers one can grabber.
RoboChair
10-04-2015, 04:40
Please tell me that entire transmission powers one can grabber.

I will do no such thing!
Matt_Boehm_329
10-04-2015, 10:17
Making an electric gokart with that?
MaGiC_PiKaChU
10-04-2015, 10:24
Making an electric gokart with that?

that makes 6HP
Matt_Boehm_329
10-04-2015, 10:31
that makes 6HP

That is more than enough for one :D
pmangels17
10-04-2015, 11:01
Is that a power take-off I see?
Matt_Boehm_329
10-04-2015, 11:07
I would love to see this thing in person
Jay Burnett
10-04-2015, 18:49
It would make sense if they were min-cims... them being unlimited this year and all...
Sperkowsky
10-04-2015, 23:17
Thats beautiful.
asid61
11-04-2015, 01:36
that makes 6HP

Peak? 133A * 12v * 12 motors = 19152w, or 25.6HP?
Dunngeon
11-04-2015, 03:30
Peak? 133A * 12v * 12 motors = 19152w, or 25.6HP?

From Andymark's website (http://www.andymark.com/CIM-motor-FIRST-p/am-0255.htm) each CIM produces 337Watts at maximum power.

337 per CIM * 6 motors = 2022 Watts per transmission assuming no power loss.

1 HP = 745.7 Watts (1)

2022/745.7 = 2.71 HP per transmission.

Edit: This is why using stall current for power doesn't work for DC motors

http://lancet.mit.edu/motors/torquepowerspeed.jpg

from this (http://lancet.mit.edu/motors/motors3.html) page

In other news, I just realized why some people use 5310RPM as the freespeed of a CIM. Assuming the CIM behaves like described in the MIT coursework, peak power occurs at 2655RPM and in the middle of the RPM range. Doubling 2655 yields 5310RPM as the max RPM for a CIM

(1) Wolfram Alpha (https://www.wolframalpha.com/input/?i=Horsepower)
Richard.Varone
11-04-2015, 17:04
Please tell me that entire transmission powers one can grabber.

Those are our 2014 transmissions on top of our 2013 transmissions, but that now give me an idea *opens inventor and starts a 12CIM can grabber*, I mean who needs a drive train anyway!
cad321
11-04-2015, 17:24
That's 33.6lbs of CIMs alone, let alone the gears (heck the gears look like steel too) on that thing. Would it be possible to get a weight on those? what on earth needs that much power?
Jared
12-04-2015, 08:14
Peak? 133A * 12v * 12 motors = 19152w, or 25.6HP?

That's how much power the transmission would require at stall, but the output power at stall is 0 hp because the motor isn't spinning and isn't doing work.

The output power for a motor is equal to force x velocity or rotational velocity x torque. At free speed, you have a large rotational velocity but no torque, and at stall, you have lots of torque, but no rotational velocity. Halfway in between is where you'll maximize power.
pmangels17
12-04-2015, 12:26
That's 33.6lbs of CIMs alone, let alone the gears (heck the gears look like steel too) on that thing. Would it be possible to get a weight on those? what on earth needs that much power?

Nothing. Nothing needs that much power. But a combination of our 2013 and 2014 drive transmissions when you stack them together and take a picture makes it look like one sweet canburglar gearbox. A two-speed power take-off canburglar.