# Motor suggestion pls!!!!!!

Can you also suggest a motor that can lift 60-70 lbs without burning out???

Thank You,
Team 4939,AllSpark9

Any motor. Assuming no friction and the proper gear ratio.

How fast and how far does it have to lift this weight? You need those numbers, and then you need to guess an efficiency of your mechanical system.

I’m sure any moped motor would work just fine.
however I’m sure a K series motor out of a student or mentors Honda would also work.

1 CIM motor going through a 12:1 versa planetary driving a 2 inch pitch diameter(1 inch R) sprocket.
Can lift a 62.5 pound(1000 ounce) load at 335RPM or 3 feet per second.
At 35 amps and 60% out of 64.7% max motor efficency.
Torque at motor 83.3 oz-in. At sprocket with no accounting for losses in 1000 oz-in at a lever arm of 1 inch.

TL:DR CIM motor handles it like a boss! 1 Mini CIM should be able to lift the load, but slower. 2 Mini CIMs should take it like a champ.

…you are aware that there are restrictions on what motors teams are allowed to use in FIRST, correct?

[quote=“R18”]
R18 The only motors and actuators permitted on 2015 FRC ROBOTS include the following:

[/quote]

I think he was joking…

Please try to be actually helpful or just don’t post.

For to the original question:

As Nemo said, it depends on the motor and the gear ratio. If you gear down a motor enough, it can lift anything, as long as there’s no friction in the gears. Practically speaking, a 1000:1 over all gear ratio is the biggest you’ll probably ever see in FRC. And that would be sloooow.

Firstly, Ken Stafford has a good (but long) video on how to pick a motor and gearbox.

Secondly, here’s a link to the 2015 Motor Performance Data that you can use with the info from Ken’s video to pick a motor and gear ratio.

If you want the short version, one of the fundamental equations is:
Power = Force * Speed or,
Speed = Power / Force

You want something that will lift 70 lbs of force. A CIM motor’s max power is 330 Watts which Online Conversion tells me is 244 foot-pounds-force/second.

So, 244 / 70 = 3.5ish. A CIM motor geared for max power can lift your load at 3.5 feet per second, assuming no friction or losses. It’s usually better to assume losses and to not aim for exactly maximum power, so a safe bet is to cut that in half and say a CIM motor can lift 70 lbs at 1.75 feet per second.

I sense sarcasm…