Although i am no not able to test it out as it won’t fit in my enclosure i do have a friend who would like to test it out on his board he understands how these switches work and has actually made a working prototype before so he could provide you with suggestions on how to improv it if needed for future irritations if your interested.
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Is he on this forum? If he’s interested in testing the prototype could you ask him to PM me?
If not, I could give you my email.
Also, on the next iteration, I think I only going to use two MOSFETs, three really is overkill. I can’t make the design any smaller without removing one of the MOSFETs. I am going to move the connectors to the sides.
EDIT: replaced the MOSFETs on phase B and ESC works again >:).
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He is but he’s really inactive here. I’ll tell him to pm you.
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Properly assembled prototypes.
Testing them tomorrow before shipping them out later this week.
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No explosions yay.
3.3mF load capacitance.
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Okay, so interesting thing happened.
The 47 ohm resistors blew up (failed open circuit).
Replaced them and works fine again.
Not sure how TWO resistors both fail open circuit.
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What’s their package? 0805 1/4W?
1206, they’re big.
Maybe I should go for 2W 2512 resistors?
Honestly they should be able to take the impulse, check the impulse rating of that specific part
42V with a 3.3mF load capacitance, I’ll check the part’s specs and the redo the math to see what kind of power dissipation they’re seeing.
So the part number is: RMCF1206JT47R0
So, the resistors see 2.2J of energy split between the two of them over a period of 200ms.
They are indeed 1/4W. I don’t think I’m reading the datasheet correctly though, can’t seem to find an overload power rating, but from what I can see, it should be able to handle overload power for a couple of seconds. Says it can handle 2.5x working voltage for 5s, which means it should certainly survive the turn-on event.
I cycled the new resistors many more times than the old ones and didn’t have a problem.
Have you built a rig to power and then drain the caps? I would definitely set something up to test the switch a few thousand times at least. My approach to this kind of testing is always to try and make it fail.
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Okay, I have no goddamn clue why this is happening, but after leaving the switch to sit in my garage for a few days, UNPLUGGED from the battery, the 47 ohm resistors again BOTH became high impedance.
Is there something wrong with my design or did I receive defective resistors?!
Honestly lgtm, I’m reaching the same conclusion as you on the resistor’s power ratings, should be fine. Maybe you need to cover that sucker in probes and see what’s happening. Then again, maybe it was a bad batch of resistors?
I give up.
Design now calls for high power through-hole resistors. Initial prototype never had a problem with them, even though those resistors were not specifically high power.
This design was meant to be easy to DiY on protoboard or on a cheap PCB. It is not suited to be put into production.
Heck, I used the IPP029N06N on the initial prototype.
On my existing prototypes, I’m going to put in 100ohm through hole resistors. Test them a bit, and if they don’t have problems, ship them out the the person who agreed to field test them for me.
After that. I’m going to be done with the design. Others are free to redesign the PCB or do fab runs of them if they like. I can’t figure out how to make it smaller without my OCD bugging the hell out of me.
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hey sorry very new to this thread have a lot to learn,
- why dont you have any by pass capacitors in the circuit or are they not required?
- why are you using 2x 47ohm resistor for NO cucorit from what l just mathed that will still allow 1.75a of current at 42v
- why didnt you just take a very good current desgin and rework the pcb desgin to make an antispark and do a copy or are there issue with that.
- also would love to get my hand on one of the e switches for testing and help out with this desgin and developemnt proccess, l have a rework station (hot air and solder)
and lam currently in the thought of want to sell anti sparks online an thought current pricing is crazy so lam either going to from a good free desgin or just 1 for 1 coyp a good one ucrrently on the market and get it made
Doesn’t need bypass capacitors, in fact bypass capacitors may actually introduce ringing into the circuit.
The two 47ohm resistors were arbitrary, they are now going to be two 100 ohm through-hole (power) resistors.
No current design works in this way and the ones that work are expensive.
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Hmm yep certainly in my simulation, those resistors take a huge current spike (120W) which will certainly kill them.
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You’d think they die during turn-on, but no, they died when the switch wasn’t plugged into anything,
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Thick film resistors can take a decent impulse especially with the relatively low time period.