Why do Hall Effect Sensors break? (UPDATE, AGAIN w new 5404)

[ryan]

I rewired my phase wires last night and had a great run today until disaster. Mid ride one of my halls blew. Confirmed with Lyen's ebike tester. First I thought it was a short from a spinning axel or something but after rewiring all the hall wires and testing with a magnet the yellow Hall on my 5304 is busted. And this is supposedly the good kind -- the originals were replaced by Ilia himself as I watched.

Anyway, what causes this?

I rode 2k miles without much problems but now I feel like I'm stringing together a record setting number of expensive "experiences". At least I'm learning something.

I don't have the good ones on hand, so I'm thinking of using a hall from my burnt out 5305.

[Spicerack]

It's electronic. The magic smoke must have escaped

[ryan]

Magic smoke. That's it. I could see it leave just as my heart sank.

Seriously though, do they just give up? Was there an undetected short somewhere? I'd like to avoid this in the future.

[amberwolf]

There is always a reason for failure, but it may not be visible.

There's mechanical failure: physical damage to the casing or leads that breaks the electrical connections. Repeated stresses on the leads at the casing can break them off right there. Can also be fractures in the casing itself, which you may be unable to see without high magnification, and those fractures could propagate either into the die itself, or across the wires or bond points to leads or die, and pull them off. I don't know how likely either is, relative to other possibilities, but lead breakage is pretty danged easy to get.

There's also static electricity, which can cause immediate failure, but usually doesn't in today's electronics. But it *can* cause latent damage, which can fail later on quite suddenly, or can cause strange behavior. *Any* handling of electronic components, even with ESD precautions and equipment, can cause ESD damage, though it is much more likely when precautions aren't used. Since it's not likely people will use precautions when handling the hall connector to plug into the controller, either at factory or in shipping/handling/packing, or installation, it's easily possible wiht most of the hall connectors out there to touch pins which will transfer any high voltage static charge on the finger to whatever pins that is, potentially damaging the halls attached to them.

The same thing can happen when the halls are being installed in the first place, at the factory (or during user repairs or mods), and is probably even more likely, as neither place is likely to use any kind of ESD protection.


Then there's Murphy and the Gremlins, who like to sneak up and break stuff at random times just cuz, but I tend to think that this is caused by one of the above.


Most of the failures of parts can be traced back to how they were handled during installation (or elsewhere in the factory using them), in my experiences of failure analysis, when I worked at Honeywell a couple decades ago. Most of the rest are in how they are used in a design, where some factor was unaccounted for in the design, and they are overstressed electrically or sometimes mechanically. A very few may be actual part-manufacturing-defects.

Since most of the sensors in these motors are probably "chinese clones" of the "real" parts, I would guess but don't know that the manufacturing process of the sensors themselves might be a source of problems, but I would still bet more on the mechanical mishandling of them, or insufficient ESD precautions, even at the parts factory and distributors between them and the final usage point, than on manufacturing defects themselves.

[ryan]

Thanks AW for that thorough answer. I picked up a set of halls (honeywell ss41) from Lyen and will try to install one all by my lonesome tonight.

In the meantime I'm upgrading this failure from magic smoke to gremlins.

Also can anyone point me to 1) hall wiring diagram (in relation to the printing on the hall) and 2) recommended epoxy (first time using it, although I watched Ilia do it last time)?

I will say I'm way more comfortable opening up these motors and rewiring what I need now. Especially after breaking open the same motor 2 nights in a row to rewire. All that's left is to learn how to rewind a motor and I'll have done it all!

[John in CR]

My only hall failure was from the wiring. After 3 yrs the insulation on my phase wires was cracking from heat stress, and while the hall wires showed no visible damage the insulation wasn't smooth and exhibited the shape of the copper strands inside. I didn't replace the hall wires and in less than a week a hall failed. I attribute it to a short in the hall wiring. If I upgrade phase wires from now on, I will also run new hall wires too unless the motor has never seen any heat stress at all.

John

[ryan]

So I replaced my broken hall with a Honeywell SS41. My magnet + Hall + LED test was successful as was my Lyen eBike tester test.

It ran 4 miles before breaking again. Same hall sensor.

Now I haven't opened the motor up yet (I didn't want to see my bike for a few hours), and I expect it's due to poor installation.

But if it isn't due to my poor installation... And before I repeat the same issue, can you imagine another reason that's more systemic? As in, could a problem exist elsewhere that would break my yellow hall no matter how perfectly I install it?

[John in CR]

Sounds like the yellow wire is shorting somewhere between the board inside the controller to hall inside the motor. Since it worked at all, then the short itself must rear it's ugly head only once warmed up. When that happened to me, I just took my large wire cutters and cut the entire wiring harness off at the axle, because I knew the likelihood of extreme frustration and time to try an track down such an intermittent short. Those motors had an early design issue cutting wires at the axle, phase wire upgrades are always a good idea anyway, and you already know how to change halls, so my suggestion is an overhaul, all new wires, halls, plus good bearings unless you did the bearings last time.

Quality halls should last the lifetime of the motor.

{edit} Sorry, wrong motor. No wire cutting on the X5 design.

[jateureka]

+1
I'd check the insulation on the wiring going through the axle and the wiring to the controller.

[ryan]

Alright I just went 15 miles on my brand new 5404 without a hitch, then hall sensor busted again.

Brand. New. Motor. Everything else the same. Dropout axel wires look solid.

What on earth could cause this?!!!

[grindz145]

Don't underestimate the result of excessive heat on an electronic component. The higher average temperature you run the motor at, the lower the estimated meantime between failures.

[ryan]

15 miles, low speed (20mph), low volts (72v) low amps (0-30A), on a motor specifically designed to avoid over heating. Motor wasn't even warm to the touch.

I feel like I have a hardware virus that attacks hall sensors. Is there any reason my controller would cause this?

[Bluefang]

Could be loose wires in the controller or connections. If its a new motor and your blowing halls then its certainly not the motor. How are your hall wires connected to the controller? Thru a 5pin plug or something? I have mine completely seperate to each other and joined together using telephone cable connectors(so easy to use for small wires) and i personaly have never had a failed hall sensor running this way but its a 9C running a max of 5kw with a low top speed so it does not run hard for long and never gets more then slightly warm. I did have a hall go on a GM motor when i was using a multi pin plug for the halls.

[hjns]

I am by no means an expert here, but I was wondering, have you checked all hall connectors up into the controller? If you break the same hall in different motors, it may be time to see what happens when you change controllers.

[jateureka]

Trace that faulty halls wiring for shorts.

[Alan B]

Sorry to hear about your hall problems, Ryan.

It does sound like a problem in the wiring harness, connector(s) or controller.

[John in CR]

Check the voltage on the hall supply. Maybe you have some kind of voltage regulator issue on the 5V rail.

[Emmett]

Quality halls should last the lifetime of the motor.

What are the best quality hall parts to get? To fit a Crystalite H40xx. Thinking mainly about heat tolerance, but also static discharge.

Thanks in advance.

[Punx0r]

I'd be surprised if you could go wrong with genuine Honeywell parts

[Emmett]

I'd be surprised if you could go wrong with genuine Honeywell parts

I'll get Honeywell for sure. Online searching I've seen the honeywell specs vary for dimensions, actuating type, max operating temp, input voltage range. I presume I need to have a specific size that fits and go for the best specs. Installing these correctly is no simple task for a first timer, so I'm hoping someone in the know can save me the time and from a mistake and tell me the part number to go for. Anyone? Please.

See http://sensing.honeywell.com/products/m ... 308&N=3094

I presume my broken H4065 hall sensors are not the best items available. So the old code is not the solution. Even if I could read it.

I do not yet know which actuating type to get.
150C max temp seems like the minimum for my needs. Also the maximum temp rating I think they make.
Input 3-24 VDC sounds pretty good. Wide range.
Do not know yet if some are rated tougher than others.

[danielrlee]

Honeywell SS41 are the ones to go for.

[Lebowski]

Check the voltage on the hall supply. Maybe you have some kind of voltage regulator issue on the 5V rail.

I second this one, maybe a spike on the supply at startup killed them. You could try to add a decent cap to the hall sensors, preferably in the motor (combined with a 50 or so ohm resistor in the supply to the halls)

[dogman dan]

Time to try a different controller I think. Unless you find the short on the wires.

[Triketech]

Alright I just went 15 miles on my brand new 5404 without a hitch, then hall sensor busted again.

Brand. New. Motor. Everything else the same. Dropout axel wires look solid.

What on earth could cause this?!!!

Try shielding the Hall wires. You may be getting an inductive spike.

[Emmett]

Alright I just went 15 miles on my brand new 5404 without a hitch, then hall sensor busted again.

Brand. New. Motor. Everything else the same. Dropout axel wires look solid.

What on earth could cause this?!!!

Try shielding the Hall wires. You may be getting an inductive spike.

Good idea. Thanks.

But note Ryan's problem was 4.5 years ago. He probably resolved it. I revived this old thread because the issue will always exist for others, like me.