Lowest Emissions Electric Motor

[David Hess]

A stepper motor could be driven by an analog quadrature oscillator eliminating switching noise.

[coppice]

Clockwork?

If we are going outside the box, we ought to consider a mouse in a wheel.

[max_torque]

Without some actual limits for noise and a definable problem this whole thing is obviously pie in the sky, but clearly the "best" solution if electromagnetic noise is an issue is to quite obviously not use an electric motor!

An air motor, or hydraulic motor, or clockwork one (as mike suggested!) or perhaps a hamster running in a wheel all are clearly quieter than ANY electric motor as none of them use electricity!  With any practical electric motor, the devil is in the details, and the precise implementation is going to domiate the emissions profile rather than the fundamental architecture.

And of course as an electric fields strength decreases with an inverse square of the distance between the emitter and the reciever, again, clearly, by far the best option is to seperate the energy conversion from the energy consumption and transmit that energy non-electrically, ie back to the air motor again etc......

[mikeselectricstuff]

And of course as an electric fields strength decreases with an inverse square of the distance between the emitter and the reciever, again, clearly, by far the best option is to seperate the energy conversion from the energy consumption and transmit that energy non-electrically, ie back to the air motor again etc......

Or simply use a mechanical coupling - shaft, chain, belt etc. to increase the distance

[coppice]

And of course as an electric fields strength decreases with an inverse square of the distance between the emitter and the reciever, again, clearly, by far the best option is to seperate the energy conversion from the energy consumption and transmit that energy non-electrically, ie back to the air motor again etc......

Or simply use a mechanical coupling - shaft, chain, belt etc. to increase the distance

A lot of the applications for ultrasonic motors are places people previously had to do just that.

[coppercone2]

How much does a piezo motor cost to replace a belt drive motor?

In some cases it seems like the kind of lab equipment that can bleed some QC or analytical place dry for no good reason.


If similarly priced its a great achievement though.

Lol, it sets off an alarm for me. Like if there is some new lab equipment that makes something spin by some other means but then its like 5000% more expensive.


I just know, there is the laboratory interior decorators ministry that will think a 2 foot long belt ruins the decour of the lab bench that's going to be empty. And they will pay 500% extra if you can replace a box shape with a mitered box shape.


Oh man I know some people if you put like a swiss rubber belt drive type mechanism in their building they won't ever sleep soundly again. Like one of those belt drive vacuum pumps. The old ones. To them its like you put a dead racoon on the table. They need the throw away "mitered" look box vacuum pump instead, so you can neatly stack them in a dumpster once they get fried


the illusion of high tech. it might make sense in a nuclear submarine, but not your lab



the machine that used to get you a reasonable pension plan! currently being replaced to ensure your workplace looks "lab-core"

[coppice]

How much does a piezo motor cost to replace a belt drive motor?

They aren't as cheap as more conventional motors, but they aren't only used in exotic applications, like MRI patient bed drives. For example Lexus uses them for the motors in its seats. They are quiet, need no brake or heavy gearing to maintain their position when the motor isn't running, and the final cost doesn't stop a Lexus being well priced against other cars using conventional motors. I looked into them for a couple of anti-tamper applications, where a conventional magnetically based motors can be susceptible to being stalled by powerful external fields.

[SteveThackery]

For example Lexus uses them for the motors in its seats. They are quiet, need no brake or heavy gearing to maintain their position when the motor isn't running...

I believe Lexus's first application for ultrasonic motors was for the steering wheel adjustment on the LS430. It was a really bad idea - they virtually all fail after a few years. Last time I checked, refurbed ones were over £300 each. When I took a failed one apart it was full of shredded black plastic. Presumably there was a plastic disc sandwiched between two metal surfaces, and it just got chewed up.  I'm sure the ultrasonic motors will be much better in the later models.

[coppice]

For example Lexus uses them for the motors in its seats. They are quiet, need no brake or heavy gearing to maintain their position when the motor isn't running...

I believe Lexus's first application for ultrasonic motors was for the steering wheel adjustment on the LS430. It was a really bad idea - they virtually all fail after a few years. Last time I checked, refurbed ones were over £300 each. When I took a failed one apart it was full of shredded black plastic. Presumably there was a plastic disc sandwiched between two metal surfaces, and it just got chewed up.  I'm sure the ultrasonic motors will be much better in the later models.

Interesting. Maybe that was a bad design. I assume you mean the adjustment of the steering wheel to the driver's size. Like the seat motors, I wouldn't expect that to be operate often enough to have any kind of wear and tear issues. The ultrasonic motors used for focus and zoom in lenses go back and forth a lot. typically spending most of their time over a small part of their range. They seem to last.

[coppercone2]

That seems like a reasonable price. The ones on google come up in the 5000 dollar range making it a little obscene for a stirrer

[BrianHG]

Clockwork?

Read 2 posts before yours:
https://www.eevblog.com/forum/projects/lowest-emissions-electric-motor/msg5583643/#msg5583643

Example:

Seek to 56:45 to see it working.

[CatalinaWOW]

Apparently OP got his answer and we will never hear what was driving his problem.

[SteveThackery]

Interesting. Maybe that was a bad design. I assume you mean the adjustment of the steering wheel to the driver's size. Like the seat motors, I wouldn't expect that to be operate often enough to have any kind of wear and tear issues.

The LS430 has a feature whereby switching off the ignition causes the steering wheel to move upwards and inwards, giving the driver more room to get in and out. The steering wheel returns to the driver's preset position when the ignition is switched on. It's a cool feature, but clearly the ultrasonic motors couldn't handle the workload. It was a rare, but serious, design mistake on the part of Toyota.

[David Hess]

The LS430 has a feature whereby switching off the ignition causes the steering wheel to move upwards and inwards, giving the driver more room to get in and out. The steering wheel returns to the driver's preset position when the ignition is switched on. It's a cool feature, but clearly the ultrasonic motors couldn't handle the workload. It was a rare, but serious, design mistake on the part of Toyota.

Maybe I missed it in the previous discussion, but what advantage did Toyota think ultrasonic motors had for that application?

Ultrasonic motors would still require some type of position encoder.

[SteveThackery]

Maybe I missed it in the previous discussion, but what advantage did Toyota think ultrasonic motors had for that application?

Ultrasonic motors would still require some type of position encoder.

You didn’t miss anything. Ultrasonic motors generate loads of torque at very low rpm, plus they are self-locking when not powered. The alternative way to get that much low speed torque is with a traditional electric motor and a gearbox. You'd need to incorporate a worm drive as well to make it self-locking. Adding a worm drive and reduction gears increases the overall size of the package. Ultrasonic motors are unbeatable when it comes to their compact size. I believe that Toyota used ultrasonic motors for their compactness and - equally important - their silent running.

[coppice]

Maybe I missed it in the previous discussion, but what advantage did Toyota think ultrasonic motors had for that application?

Ultrasonic motors would still require some type of position encoder.

You didn’t miss anything. Ultrasonic motors generate loads of torque at very low rpm, plus they are self-locking when not powered. The alternative way to get that much low speed torque is with a traditional electric motor and a gearbox. You'd need to incorporate a worm drive as well to make it self-locking. Adding a worm drive and reduction gears increases the overall size of the package. Ultrasonic motors are unbeatable when it comes to their compact size. I believe that Toyota used ultrasonic motors for their compactness and - equally important - their silent running.

I think it was more simplistic "A Lexus LS needs silent motors" thinking, and all the other plus points followed.

[SteveThackery]

I think it was more simplistic "A Lexus LS needs silent motors" thinking, and all the other plus points followed.

Yeah, maybe. Probably. It's hard to know, 20+ years later. I'm inclined to agree that silent operation is probably the most important requirement. Having worked on the Lexus, it's clear that the small size was a desirable bonus.

[coppercone2]

I think not having a gearbox is the most appealing factor.


Now we need a ultrasonic motor kitchenaid stirrer. In the back of my mind I am wondering how many loaves of bread it can make before the worm gear strips again

[Terry Bites]

Could you mix using a fine stream of bubbles instead of a stirer? Use an aquarium air Stone and a bottle of argon.

Ever touched a portable radio antenna with a metal thingy. Crackle crackle!
Pneumatic, hydraulic and clockwork will all create low level RFI as metal parts move against each other.
Pneumatic motors can create a lot of static.

Put the motor in a shielded grounded box. Ground the final bearing and or motor case and put a grounded slip ring on the shaft.
Join the motor to the stirer with a nylon shaft coupler. Fit a nylon bearing where the shaft exits the box.

[coppice]

I think not having a gearbox is the most appealing factor.

In a lot of applications that use ultasonic motors, the enormous torque needed to turn them externally when they are idle is a huge plus. It can eliminate an entire braking scheme.