CIM Motor Sacrifice

[Roboticsismylif]

Originally Posted by androb4

I was wondering how many people are thinking of sacrificing their CIM motors to use on their ball shooter or something else and just have 2 CIM's on the drivetrain.

My team is using two CIM motors to power our robot. Last year we used two motor two power and it worked fine. We had a six wheel drive. The two center wheels had the power and the four outer wheels were "omni" wheels just for support. As for a shooter we are going to use the other two CIM motors

[billbo911]

Originally Posted by Roboticsismylif

My team is using two CIM motors to power our robot. Last year we used two motor two power and it worked fine. We had a six wheel drive. The two center wheels had the power and the four outer wheels were "omni" wheels just for support. As for a shooter we are going to use the other two CIM motors

Just a word of caution if you plan on using the same drive train this year, climbing the ramp will be difficult at best.

[JamesCH95]

Originally Posted by Roboticsismylif

My team is using two CIM motors to power our robot. Last year we used two motor two power and it worked fine. We had a six wheel drive. The two center wheels had the power and the four outer wheels were "omni" wheels just for support. As for a shooter we are going to use the other two CIM motors

Not a rhetorical question: have you ever driven a 4-cim robot?

[Ludicium]

FP motors are better, because you can achieve a higher speed (roughly 19,000rpm) if i am not mistaken. And if you were to create a fly wheel launcher you could overcome the lack of torque a FP provides. Also once you are up to speed you only require minimal current to sustain the launcher. But dont go quoting me i could be wrong. Feedback?

Also the only problem I can see is connection between motor and wheel, direct drive would be best.

[the man]

Just saying we tested a fisher price to day and to keep two 8inch wheels spinning on a 4:1 reduction drew about 9amps. And it did get kind of warm.

[PayneTrain]

We're going to be CIM-SIM-ing our lift with the Fisher Price motors and we'll be CIMULATOR-ing the launcher with two RS-775s. I heard good things about BaneBots this year and we want to keep all 4 drive CIMS.

If the BaneBot motors become the bane of my existence again, we may go to a hooded one wheel with a CIM-SIM and change our conveyor to a window motor.

Here's to hoping we can pull off "7" CIMs on our robot, in addition to a pneumatics set.

We're going to weigh our bot week 4 and it's going to be 200 pounds and I will die.

[Aren Siekmeier]

Originally Posted by Ludicium

FP motors are better, because you can achieve a higher speed (roughly 19,000rpm) if i am not mistaken. And if you were to create a fly wheel launcher you could overcome the lack of torque a FP provides. Also once you are up to speed you only require minimal current to sustain the launcher. But dont go quoting me i could be wrong. Feedback?

Also the only problem I can see is connection between motor and wheel, direct drive would be best.

I think you need to rethink this. Is an FP at, say, 12:1 better than a CIM at 3:1 (assuming an FP spins 4 times faster than a CIM)? It is better than an RS 775 geared to the same speed, by a torque comparison, but this is not because its ungeared free speed is higher.

Up to efficiency losses, motor power is pretty much all that matters.

[Ether]

Originally Posted by compwiztobe

I think you need to rethink this. Is an FP at, say, 12:1 better than a CIM at 3:1 (assuming an FP spins 4 times faster than a CIM)?

piggybacking on the above..

@Ludicium, read this:
http://www.chiefdelphi.com/forums/sh...7&postcount=34

[Aur0r4]

Careful.... The RS-775 is rated at 18v. At 12v, it is less powerful than the RS-550, making the RS-550 the highest power output available after a CIM to FIRST teams. We chose it last year to raise our boom (at significant mechanical disadvantage) and it really packs a wallop.

Also, remember the FP motors have integral worm gears that can't be legally removed. So while the FP motor specs are pretty good, the worm drive makes it unsuitable for anything other than low-speed, torquey applications.

[Ether]

Originally Posted by Aur0r4

Careful.... The RS-775 is rated at 18v. At 12v, it is less powerful than the RS-550, making the RS-550 the highest power output available after a CIM to FIRST teams.

Not true.

The RS-775-18 running at 12 volts is more powerful than the RS-550 also running at 12 volts.

[RufflesRidge]

Originally Posted by Aur0r4

Also, remember the FP motors have integral worm gears that can't be legally removed. So while the FP motor specs are pretty good, the worm drive makes it unsuitable for anything other than low-speed, torquey applications.

Also not true.

The FP does not and has never (as far as I know) come with a worm drive, you are thinking of one of the various Window motors from this or previous kits.

[JamesCH95]

Originally Posted by Ether

Not true.

The RS-775-18 running at 12 volts is more powerful than the RS-550 also running at 12 volts.

Originally Posted by RufflesRidge

Also not true.

The FP does not and has never (as far as I know) come with a worm drive, you are thinking of one of the various Window motors from this or previous kits.

Came to post exactly this.

[Aur0r4]

WRT the FP motor, you're correct, thats my mistake!

@Ether

Perhaps I am wrong (and there's always an opportunity to learn) but we went through the specs last year and we were unable to find anything that showed that the 18V version running at 2/3 the nominal voltage performed better than the RS-550 at nominal.

[commonsense]

Keep the CIMs on the wheels. Put a CIM-SIM for your launcher. Especially for maneuvering onto the bridges at the end, you will not want two motor tank drive, seeing as the bridges are flush to the wall.

[Daniel_LaFleur]

Originally Posted by Aur0r4

WRT the FP motor, you're correct, thats my mistake!

@Ether

Perhaps I am wrong (and there's always an opportunity to learn) but we went through the specs last year and we were unable to find anything that showed that the 18V version running at 2/3 the nominal voltage performed better than the RS-550 at nominal.

The data on this page shows the 18V version specs at 12V (although you are right ... it doesn't specifically say it).