Turning Stepper Motor Off

@inq

As long as the stepper drivers are powered up, the steppers are using energy to hold their position, even if nothing is trying to rotate them.

You can use the "Enable" to disable them and they'll stop burning, but they won't hold position either. Depending on the driver, there may be a "sleep" state available too.

In my experience, active steppers always seem to run the temperature up to about 1st degree burns - 5 degrees.

@will EDIT, sorry guys, I will move this to a new thread, I got carried away.

I think that rules out my plans for stepper motors, is a servo the only other choice? Can a servo work with objects it will move in the 5 to 10 lb class? I need one motor to rotate 10 lbs around the vertical axis at maybe 2 rpm and a second motor at 90 degrees to the first at 2rpm also. All the servos I have seen are small and looked delicate. If they are is there a 3rd choice.

The first motor mentioned could be a stepper and be turned off when it got in position since there isn't anything to cause it to move. The second motor is the problem, the load would make it tip.

Posted by: @will

You can use the "Enable" to disable them and they'll stop burning, but they won't hold position either.

Are you Snipe hunting me?  😆 

@zander 

Yes, you could use a servo to rotate the weight, especially if the weight rotates horizontally and is supported (i.e. the servo doesn't have to overcome gravity in both directions).

I can't visualize what you mean by the second rotating at the same speed at 90 degrees. That sounds like one or the other (or both) will need to counteract gravity and that means they'll need to be stronger and therefore much more expensive.

You'll also need to look for "continuously rotating servos" since they'll go freely through 360 degrees, whereas normal servos are restricted to a limited arc less than a full circle.

I've only used the "toy" servos like the ones used for RC aircraft controls.

Posted by: @inq

Posted by: @will

You can use the "Enable" to disable them and they'll stop burning, but they won't hold position either.

Are you Snipe hunting me?  😆 

Sorry, don't know what "Snipe hunting" means.

Posted by: @zander

@will EDIT, sorry guys, I will move this to a new thread, I got carried away.

I think that rules out my plans for stepper motors, is a servo the only other choice? Can a servo work with objects it will move in the 5 to 10 lb class? I need one motor to rotate 10 lbs around the vertical axis at maybe 2 rpm and a second motor at 90 degrees to the first at 2rpm also. All the servos I have seen are small and looked delicate. If they are is there a 3rd choice.

The first motor mentioned could be a stepper and be turned off when it got in position since there isn't anything to cause it to move. The second motor is the problem, the load would make it tip.

They make some honk'n servos... 

https://www.amazon.com/BETU-Servo%EF%BC%8CFull-Waterproof-Stainless-Horn%EF%BC%88180%C2%B0%EF%BC%89/dp/B094VTNG67/ref=sr_1_3?crid=1JKMJC9AJ7VD9&keywords=big+servo&qid=1651708674&sprefix=big+servo%2Caps%2C32303&sr=8-3

What's ya make'n?

@will It was sounding ok until I realized that when the other motor (a stepper) kicks in it naturally destabilizes the platform with the load.

Think of a video camera tripod. One motor to pan and another to tilt. As long as there is NO tilt, panning is easy since the load is almost all straight down the drive shaft although some sort of gearing might be wise. BUT when the tilt motor moves the previosly level tripod the pan motor now has a much bigger hill to climb so to speak. I think steppers are required in both cases, and the addition of a brake will hold them but the brake might use as much or more power as a 'held' stepper.

OR if I create notches every x degree and then instead of a brake a detent that only has to be powered when moving. Since moving is a small part of the time frame, this optimizes power consumption.

I think that will work, time to start a prototype. Thanks.

@inq It's a secret.

Posted by: @will

Sorry, don't know what "Snipe hunting" means.

Boy Scout hazing thing... you send the rooks out in the woods to bring back a Snipe.  

The Stepper class doesn't have an Enable either.  But I fell for it and dug out the code.

@inq What does the 45Kg refer to, wt down thru the shaft, or around the shaft, HUGE difference.

EDIT, just realized it's 45Kg force probably.

@zander 

But if a servo is loaded up... it'll use power to hold position like a stepper.

@inq Yes, but at that time I was thinking it didn't need to then I switched to both steppers with detents. 

HEY, we are still in @Inq's thread not my new one. Sorry.

@inq We had Snipe one thanksgiving at my brothers place. Did it in a wood stove, very tasty, something like liver.