Checking out Jordan's failed Rolec breaker

In 12 years I've never had a breaker fail for an Electric Forklift Battery Charger. In the US we generally use, at most, 48 volt batteries, around 1200AH. A charger for that could have an output up to 56volts at 250amps. Something that big would be on 480vAC 3ph.

Scrufdog

The bimetallic strip will give the RMS value. It would integrate the high current spikes to an average value. The solenoid trip wouldn't be able to respond fast enough to the pulses, so it too would average them.

Big Clive

I didn't. I think it had failed open circuit due to the plastic interfering with the contact closure.

Big Clive

I don't think a spiky current alone would cause this. The bimetallic strip measures broadband RMS by heating. It should always ping before charring occurs.

Mike Page

Interesting. You didn't happen to measure the "on" resistance before disassembly I suppose?

Mike Page

Good 'leave no finger prints' tip. Plus you don't disturb the existing prints.

Stevan Farkas

...which doesn't really work on the patreon phone app 🤪

Phil in the kitchen

🟦🟦🟦⬜🟦🟦🟦⬜🟦🟦⬜⬜🟦🟦🟦 🟦⬜🟦⬜🟦⬜⬜⬜🟦⬜🟦⬜🟦⬜⬜ 🟦🟦⬜⬜🟦⬜⬜⬜🟦⬜🟦⬜🟦⬜⬜ 🟦⬜🟦⬜🟦⬜⬜⬜🟦⬜🟦⬜🟦⬜⬜ 🟦🟦🟦⬜🟦🟦🟦⬜🟦🟦⬜⬜🟦🟦🟦 LED matrices too! ☺️

Phil in the kitchen

Cerity bitte. ----(🟩⬛🟥 👑)---- or ----(🟩⬛🟥 🟨)---- or ----(🟩⬛🟥 ⬜)---- perhaps, at a push?

Phil in the kitchen

Phil danke⁉️ we have emoji color swatches for resistors, no silver or gold though🎊👌

Cerity

Nice one. I believe Clive has found it to be a... ----(🟩⬛🟥 )---- …but it's a great thought.

Phil in the kitchen

In the final shot, isn't the resistor hiding in the top right hand corner of the unit? Hope it's 2.2k, in a Where's Wally homage.

Yes, but only with this type. Some have more active circuitry and a small solenoid.

Big Clive

They will only ever see low voltage at low current under fault conditions. Literally about half a volt at around 20mA.

Big Clive

They do cap the voltage to around 0.6V, but the trip coil only requires a fraction of a volt to trigger.

Big Clive

So, with plastic consumer unit cases and if I knew the wall that the consumer unit was mounted on could I go on the back side with a large neodymium magnet or a powerful electromagnet and trip all the breakers?

Lostngone

I'm not 100% certain on how they work. My understanding is that it limits the rate of change in current draw. A friend suggested this to me as they use it for filtering VFDs at his plant. The generator couldn't accurately measure the current draw and the voltage regulator would go out of tolerance and shut the generator down. This seems to have been fixed. We had a similar issue at data centers but we just oversized everything.

Tantalum caps in there. Would have thought tantalum wouldn't be allowed, due to their propensity to ignite.

I think that there may have been a time where the contact hasn't made fully and left a bit of pitting. The contact will slowly decay after that anyway but with a pulsed load, it will be acting as a spark gap intermittently. That would definitely cause a rapid failure. Sounds like they have a bit of a design fault for that kind of work.

Paul Noble

Do the inductors increase or decrease ringing in the circuit? I know they’re used to pulse the frequency higher for solar lights, making the same mAh go much farther time wise

Cerity

Hang on. How is that sense coil circuitry working at all? I'd think that two inverse parallel diodes would shunt current in both directions before it reaches the rest of the circuitry? Is it not the equivalent of a dead short? Or does the diode voltage drop (that is, resistance) suffice to charge the capacitors up and power the release coil? Am I missing something here?

horrovac

My company services industrial equipment and I think you are on to something. The problem is that your average factory owner is a skinflint and doesn't care as long as the myth of limitless growth is being expounded.

Michael Thompson

I worked in big data centers which is a similar load: lots of small switch mode power supplies. We had some strange persistent breaker failures (200A 3ph 240/120) which we never figured out. We had a lot of issues with harmonics and panel heating, too. I have a tankless water heater which is PWM driven. It caused problems for my generator which was fixed by installing line reactors. Perhaps car chargers should have beefy inductors in circuit.

I didn't. In the cover letter he called himself Jordan Farley. He may be choosing to use an "artisan" name.

Big Clive

Jordan is his middle name. His first name is Andrew. I bet you didn’t know that!

Gadgetman

i’ve been waiting for this to come out

Gadgetman