Has anyone moved 40lbs using 4 sets of 10lb motors?

[jamesmatheson]

Problem Statement: 40 lbs
Relevant Equations: 10 times 4

I wanted to know if anyone has moved 40lbs using 4 sets of 10lbs motors

instead of a motor that can move 40lbs

I am testing using 4 small motors instead of 1 big motor

thank you

 

[berkeman]

Welcome to the PF.

What is the setup? lifting the weight vertically? Pulling it horizontally against friction? What is your coupling mechanism? Chain, Rope, linear screw, rack and pinion?

 

[berkeman]

Also, motors are usually rated in terms of torque or power, not force. Can you say more about what you are wanting to do? Thanks.

 

[russ_watters]

Also, motors are usually rated in terms of torque or power, not force.

Can I say this stronger? The phrase "10lb motor" is tooootaly meaningless.

 

[DaveE]

Gears, ramps, pulleys, etc

 

[jamesmatheson]

Welcome to the PF.

What is the setup? lifting the weight vertically? Pulling it horizontally against friction? What is your coupling mechanism? Chain, Rope, linear screw, rack and pinion?

It's a merry go round thinking
Here's the idea
https://photos.app.goo.gl/jhCtaTuvJ2g7N6RX9
Really simple like 4 people can move 100 lbs in a circle with more efficiency than 1 person

My explanation isn't very good

Thank you for your reply

 

[jamesmatheson]

Can I say this stronger? The phrase "10lb motor" is tooootaly meaningless.

This explains better
https://photos.app.goo.gl/jhCtaTuvJ2g7N6RX9
My word explanations aren't the best

Thank you for your reply

 

[berkeman]

It's a merry go round thinking
Here's the idea
https://photos.app.goo.gl/jhCtaTuvJ2g7N6RX9Really simple like 4 people can move 100 lbs in a circle with more efficiency than 1 person

It looks like you want to connect the 4 motors in series to try to add their torques or powers. I'm pretty sure you will need to connect them in parallel instead to try to increase the overall power output. Think about the tension in the chain or whatever you will use to connect the motors to the load. If it's one chain going around the motors and the load, then that one chain has to carry all of the tension. I don't know how series motors can share that load. If each motor has its own coupling chain to the final drive, each of those chains carries one quarter of the final output tension...

 

[jamesmatheson]

Also, motors are usually rated in terms of torque or power, not force. Can you say more about what you are wanting to do? Thanks.

it is 4 motors with 10lbs of torque rewinding a 32 lbs spring thank you
I was told it works and have a team working on it right now

 

[berkeman]

I guess maybe it's possible. After all, you can series up people pulling on a rope in a game of tug-o-war, and it basically adds the pulling force of each to add more tension to the rope.

 

[jrmichler]

It is definitely possible, but there are control challenges. These people have been building cutoff knives with one, two, and even four, motors per level for over 20 years. The two knife cylinders are geared together, and the motors are geared to the knife cylinder gears. https://marquipwardunited.com/docs/marquipliterature/dual-rotary-dd-knife-english.pdf?sfvrsn=4

Their previous generation knife used smaller motors, with up to eight in parallel per level. Most of their knives are two level, so one knife could have 4, 8, or 16 motors.

IMPORTANT NOTE: Controlling the motors can be a real challenge with off the shelf motor control software. The Marquip engineers wrote their own software to control the knife motors.

BTW, those liquid cooled motors are rated 225 ft-lbs RMS torque and 600 ft-lbs peak torque, and are about 9.9" OD and about 16" long from faceplate to backplate.

 

[Joe591]

The tricky thing with parallel operation is that even though all of the motors are the same, there will always be slight differences due to manufacturing variances. The load might not be shared by all motors equally even though they are all geared together and forced to run at the same rpm. I'm not a expert on motor control or anything, but I would think that you should at least watch the currents that are being fed to the motors. If you can control the voltages to each motor individually I think it would also be good. If one motor's current is significantly lower or higher than the other three it means something is wrong. It could even be that the motor is being driven as a generator (in a very extreme case). If you are watching the current for each motor, then at least you have something to work with. There might be better parameters to watch, but maybe talk to your team about that and come up with an effective plan.

This is all assuming that you are using a very simple control scheme. If you are using PWM or anything I imagine it would be even more complex, but I don't feel like I'm in a position to really talk about that.