Sensored or not sensored?

[macribs]

Reading threads here there are often strong feelings about motors and Hall sensors.
I realize sensors might fail, but even so more and more controllers will have an option to run sensorless as well.

And even if you for some reason do not fancy sensors, why so strong feelings about them? I mean use em or don't it is your choice.

Is there any advantages to run a set up sensorless that I am unaware of? I mean we can read pages on pages of why to use sensors in motors, and there are even kits to allow for adding sensors to motors that came without sensors. But it is hard for me to find reasons not to use sensors.

 

[chvidgov.bc.ca]

I'm running most of my direct drive bikes, including 9c, Crystalyte 406, and GoldenMotor DD, sensorless. I don't think you sacrifice much other than instant startup and a bit of smoothness/loudness on the motor. The bikes only have to be moving at less than 1/2mph to start up. The benefits are worth it to me in terms of reduced complexity. This may not be so for others though. The cheap sensorless controllers like the KU123 are pretty good.

 

[macribs]

And you would not consider taking maximum use of all functions in todays controller more important then the ability to choose a wider range of controllers and a less complicated setup? And what is that anyway? Less complicated? If you have a motor with pre installed sensors then just hook it all up and you are set.
What about more precise timing, smoother operations and less noise? I think I take that over no sensors any day.
I mean if sensors fails many controllers will switch to sonsorless mode even without user input.

But thin again I am new to this and have not even started building, maybe the available sensors are too low quality or have a poor life span so it is more a question of when they will fail rather then if they will fail.

What do others think, are sensors prone to failure? Other then from over heating?

 

[littleskull99]

I went sensorless in order to upgrade the phase wires to thicker wire. Theee wasnt any room left for halls..

 

[macribs]

I went sensorless in order to upgrade the phase wires to thicker wire. Theee wasnt any room left for halls..

You could mount outside the can, I think.

What is the benefit of thicker phase wires?

 

[snellemin]

For hills, a high powered bike and offroading I like to run sensored hub motors. For my mid drive offroader and mid powered hub motor bike, I run sensorless. I can't hammer the throttle with a sensorless controller like I can with a sensored controller, when I'm pushing more power than the controller is rated for.

Say for example Lyen 18fet sensored and sensorless controllers:
Both are rated for about 5000W.
Both do Regen.
Both have 3 speed limiter.
Both can run the same voltages.
Both can run above rated power.
Throttle tamer is required for the sensorless controller when pushing about the rated power. Your controller will cut out from getting out of sync.
You can program above 100% throttle setting with the sensored controller.
Instant acceleration with sensored controller from any speed, when pushing above rated power.
Sensorless requires more voltage for increase in top speed.
Sensored can use up to 120% throttle for increase in top speed without additional voltage.


But in my RC hobby, I prefer sensorless all the way.

 

[Ypedal]

In the days of Wilderness Energy and early Crystalyte, the crappy pedal first sensorless controllers sucked balls.. but more recent controllers now on the market are fine..

When possible, use sensored for smoothest possible starts, but either work fine if you get recent tech

 

[parabellum]

I went sensorless in order to upgrade the phase wires to thicker wire. Theee wasnt any room left for halls..

You could mount outside the can, I think.

What is the benefit of thicker phase wires?

I believe, He speaks about hub motors and space in the axle is very limited on most bicycle hubs. Thick phase wires heat less, they actually take heat out of winding phase wires in some extend. There is no easy way to mount external halls on most hubs.

 

[macribs]

I went sensorless in order to upgrade the phase wires to thicker wire. Theee wasnt any room left for halls..

You could mount outside the can, I think.

What is the benefit of thicker phase wires?

I believe, He speaks about hub motors and space in the axle is very limited on most bicycle hubs. Thick phase wires heat less, they actually take heat out of winding phase wires in some extend. There is no easy way to mount external halls on most hubs.

Is that like a golden rule for all electrical motors? The bigger the better? Or does it apply mainly to large diameter hubs?
And the reason motors are not fitted with best possible wire or thickest possible wire is mainly cost then? Or could there be other
drawbacks to such an approach? I remember we toyed with some copper winding to use as cross filters during my car stereo days.
And winded copper is also used as resistance as well. Could anything like that play a part or is it just to cut costs?


Well even so hubs might be filled with copper there is third party solutions to mount hall sensors externally even for hubs. Or you might even get away with placing tiny magnets on you rear brake rotor and place the hall sensors there What I mean is that they don't have to be inside.

Here is one example of external sensors, there are various others as well from other companies.
http://www.timken.com/en-us/products/motion/Pages/default.aspx

 

[parabellum]

Well even so hubs might be filled with copper there is third party solutions to mount hall sensors externally even for hubs. Or you might even get away with placing tiny magnets on you rear brake rotor and place the hall sensors there What I mean is that they don't have to be inside.

Here is one example of external sensors, there are various others as well from other companies.
http://www.timken.com/en-us/products/mo ... fault.aspx

You are always welcome to implement this solution and make it available to the community.

P.S. the external hall/magnet ring will also consist of 46 carefully arranged magnets (for HX series for example) all this must be sealed to avoid collecting derbies and oxidation. Easy-peasy right? :wink:

 

[macribs]

Well I don't know if it is easy but it sure seems doable. Mind you I have not tried it myself I have only read about it.
But once I got a link to after market hall sensors for RC motors. And for the fun of it I browsed to see if there was any for hubs as well. There are a few but how well they work and how easy they are to get working I don't know.

But as far as my understanding Hall sensors uses the magnets to tell turns right?
So if you make a double sided enclosure and put in as many magnets as your hub has and that has about the same diameter as the hub when mounted onto the side of the motor it would turn in sync with the motor. As it is in sync the halls can be placed in that enclosure rather then in the hubs, and you can seal up the enclcosure to avoid water/debris penetration. And for this you could use any magnets as long as they lined up like on the motor.

Either my understanding of how hall sensors are way off and I must do the reading again or this must be a sure way to enjoy hall sensors even if there is no room inside the hub.

 

[parabellum]

There is tlenty of space inside the hub, the bottle neck is the axle (Groove or hole) where all the wiring exits, at least how it comes from manufacturer. Axle or bearing mode is the way to go, but it is not cheap.