Hall sensor interchangeability SS41

[Oakwright]

So, my halls are dead. They are SS41F, and I figured for simplicity I would replace it with the same sensors. However, it apparently is rather hard to find SS41F. No one has them in stock (I checked Digi-Key, Mouser, and about two dozen other places). Digi-Key told me it would be an 8 week wait and 1000 min order, and Mouser hasn't gotten back to me on how long the wait will be.

So, I'm wondering if maybe I could use a different sensor. How interchangeable are these things? How much difference is there between each of the SS41 series?

 

[dnmun]

i still have some, did you look at at mouser? they have the honeywell SS41 which is what you want.

 

[Oakwright]

See that's the thing, I had the SS41F, not the SS41 on my motor. Note the difference in the F. So what I am asking is if that F makes any difference. Sure Mouser has SS41 in stock, but they don't have SS41F. So that's why I'm asking if the F matters.

The only difference I could find when looking at Mouser was the operating voltage range. The SS41F can handle voltage between 3.8v and 30v, the SS41 can handle voltage ranges between 4.5v and 24v. But it doesn't even mention what the different Gauss ranged they toggle at. But there are actually well over a dozen variations of the SS41x sensors, all with slightly different stats, temperature ranges, voltage ranges, Gauss ranges...

So what I am asking is: Does it matter which type of SS41 hall sensor is used? Or for these bike motors is it an imprecise enough art that it doesn't really matter which one you use?

Edited to add these links for example of difference between SS41 and SS41F:
http://www.mouser.com/ProductDetail/Honeywell/SS41/?qs=sGAEpiMZZMtdU8v/CHkq39AvnkiVL6ci
http://www.mouser.com/ProductDetail/Honeywell/SS41F/?qs=/fq2y7sSKcKYHwRh5bjaxw==

 

[dnmun]

you had a chinese motor with a chinese knockoff of the SS41. the F means nothing except to identify the factory that made it.

 

[amberwolf]

Comparison of SS41F, SS41, SS411A, SS411P from Mouser. Shows not much difference between them, spec-wise. I am using SS41 in my powerchair experiment, and they work fine. It works just like a hubmotor.

click for readable version

 

[Oakwright]

K. Sounds like the differences between ss41f, ss41 doesn't matter on these things... I'll get the one that is in stock then!

 

[dnmun]

AW, there was no SS41F on his motor. it said 41 and had an F over to the side. it is not a honeywell part, it is a knockoff.

 

[Oakwright]

@dnmun, you might be right that it is not an SS41F from Honeywell... however, it is clearly marked as 41F. The F is not over to the side.

You can see it here:


You can click on it and zoom in and see it. I went ahead and flipped and zoomed it:


So... The fact that it is clearly stamped "41F" is the reason I assumed that it is a knock off of the Honeywell SS41F, not the SS41. That and in the other thread AW linked me to the 41F on Mouser.

But really, I didn't start this thread to bicker about what exact sensor is in my motor. My question was:

How interchangeable are these things? How much difference is there between each of the SS41 series?

When I looked up the spec difference between the SS41F and the SS41 on digikey, it gave more info than Mouser. Such as the fact that the 41 trips at 150G and releases at Release, while the 41F trips and releases at 110. So there might be pros and cons to using different chips, but maybe the differences aren't noticeable on bike motors, which is the impression I am starting to get.

 

[dnmun]

if it was a honeywell part, it would be stamped SS41. the chinese cannot do that because it violates trademark rules.

 

[Oakwright]

if it was a honeywell part, it would be stamped SS41. the chinese cannot do that because it violates trademark rules.

Right. I'm not saying it's a Honeywell part. But it is perhaps an imitation of the Honeywell part SS41F, not an imitation of the Honeywell part SS41. It would seem reasonable to think that a part stamped "41F" is more similar to an "SS41F" than a "SS41".

But again... I don't care about if my previous halls were genuine Honeywell, or knockoffs. What I was curious about is if anyone could tell the difference between SS41F and SS41 (as well as any other hall sensors in that series). They each have different traits, and I was curious if those different traits make a difference on bike motors. I think perhaps my first post wasn't clear enough in that sense.

 

[ZOMGVTEK]

As long as the magnetic flux is strong enough to toggle the hall without damaging it, and they're rated for the voltage you are using, it does not matter.

Honeywell SS41's are whats recommended. Coat them with silicone to reduce future water damage.

 

[amberwolf]

I'd use polyethylene (I think tha'ts the kind) rather than silicone, because silicone will attract water.


I only put up the comparison including that because it shows little difference between the types suggested vs the type marked on it.

Mostly it is in supply voltage ranges. Since the 5V supply to the sensors from the controller shouldn't vary that much, then even ones that run on 4.5V minimum should still work fine. They don't need to sink much current, so any of the ones listed can do that job, too. The only other potential difference that could really matter is (as you found) in how sensitive to the magnetic field changes they are, but that doesn't matter becuase they are right next to the magnets, just across the airgap from them. The field is so strong that the least sensitive ones would work just as well as the most sensitive.


Part of the point of the chart was that the SS41 halls that Dnmun has offered to send you should work just fine (assuming the rest of your motor, controller, and wiring is ok).


I linked you to the SS41F because it is one possible one that you could use, but I also linked you first to the SS41 plain version because I know those work in my own motor.

 

[Oakwright]

Mostly it is in supply voltage ranges. Since the 5V supply to the sensors from the controller shouldn't vary that much, then even ones that run on 4.5V minimum should still work fine. They don't need to sink much current, so any of the ones listed can do that job, too. The only other potential difference that could really matter is (as you found) in how sensitive to the magnetic field changes they are, but that doesn't matter becuase they are right next to the magnets, just across the airgap from them. The field is so strong that the least sensitive ones would work just as well as the most sensitive.

Perfect! Just what I was trying to get at. So perhaps in other uses the different sensors would have different affects, but for our motors it's a non-issue. That makes perfect sense. So folks don't use the SS41 because it's inherently "better", but just because it's the easiest to get.

Only slightly related musing:
I noticed some of the sensors had a pretty high voltage range they could handle. I've also noticed that one of the common issues is the phase wires getting damaged and shorting out hall sensors. It makes me wonder if you have sturdy enough hall sensors and a weak enough battery if you could completely prevent halls from dying due to shorts. They could still die for plenty of other reasons (such as water and corrosion in my case) though. So say you have the SS41F, which says it can go up to 30v, and your battery was 24v, then it should be pretty much impossible to fry your halls. Although, it makes me wonder if it would then pass that 24v right up to your controller and fry it. Of course, if your phase wires are shorting out you probably have other problems too... That and I wouldn't want to run on just 24v battery, although my wife probably could.

 

[amberwolf]

I noticed some of the sensors had a pretty high voltage range they could handle. I've also noticed that one of the common issues is the phase wires getting damaged and shorting out hall sensors. It makes me wonder if you have sturdy enough hall sensors and a weak enough battery if you could completely prevent halls from dying due to shorts.

That might help if it was shorting to the Vcc input (power supply pin) of the halls, but that would then still blow your controller's 5V supply, probably.

If it shorted to the signal wire, probably the voltage tolerance of the supply of the hall would make no difference to the result. if you short the output directly to a voltage, it would have to sink current at whatever rate the internal resistance of the sensor and the rest of the current path allows, rather than thru the pullup resistor that limits it normally.

I don't know what that current would be, but I suspect that even at 5V, it'd be more than the sensor could handle. At anything close to the full supply voltage I expect it would definitely be too much. You'd have to read the spec sheet to be sure.

However, at voltage low enough to not blow halls, it's unlikely you'd have enough torque on the wheel to worry about spinning it in the dropouts in the first place.

 

[Oakwright]

True. And most likely those signal wires can't take that much anyways, so you would probably have melted insulation on the signal wires. Maybe it's a good thing halls blow first since they are relatively easy to replace.

However, at voltage low enough to not blow halls, it's unlikely you'd have enough torque on the wheel to worry about spinning it in the dropouts in the first place.

Ha! So very true.

 

[RoadShear]

I would just go ahead and order any genuine Honeywell SS41 hall sensor that is available.

SS41 Bipolar Hall Sensor from digikey is what I ordered and it worked great.

It works very well so far for every hub motor repair I did. It should work just as fine in your case.

Just order them and your motor will be happy again.

 

[Bokka]

HI,

I also ordered the SS41 Hallsensors... before I did, I wrote with Honeywell, and this is what they answered as the main differences:

Thank you for your interest in Honeywell Sensing and Control. Please see some of the noted differences below.

SS41
Switching Time Rise (10 % - 90 %) 1.5 µs max.
Switching Time Fall (90 % - 10 %) 1.0 µs max.
Operate Point 15.0 mT [150 G] max.
Release Point -14.0 mT [-140 G] min. @ 25 °C
Supply Current 15 mA
Differential 4.0 mT [40 G] min.

SS41F
Switching Time Rise (10 % - 90 %) 1.5 µs max.
Switching Time Fall (90 % - 10 %) 1.0 µs max.
Operate Point 11.0 mT [110 G] max.
Release Point -11.0 mT [-110 G] min. @ 25 °C
Supply Current 10 mA
Differential 5.0 mT [50 G] min.

http://sensing.honeywell.com/product-page?pr_id=36147
http://sensing.honeywell.com/product-page?pr_id=55911

I guess so too, that it will work fine