Electronics > Projects, Designs, and Technical Stuff
Solid state circuit breaker by Atom Power
schmitt trigger:
Same experience here....Semiconductors fail short.
HackedFridgeMagnet:
I think the IoT aspect is not really interesting as you could do that with existing technology.
But if this breaker technology isn't bullshit and can be done at a reasonable price point then you would have to assume that eventually the price point would come done and the reliability would come up to the point where it is the superior breaker, and also superior contactor.
But I've got the feeling I will be waiting a while.
In the meantime I am still wondering what is in the box.
Tims conjecture seems plausible. Though I thought it said somewhere 100kA breaking capacity. That would be impressive for a semiconductor.
--- Quote from: T3sl4co1l on May 23, 2019, 03:29:50 pm ---
More likely, if it is still a semiconductor switch, it's got MOVs on both sides, limiting peak voltage to about 900V, so that 1200V FETs can be used (1700 or 2000V if simultaneous and opposing surge is also to be protected against; that might be relevant under EMP conditions -- very close lightning strikes, say).
--- End quote ---
T3sl4co1l:
Yeah, 100k not gonna happen, more likely it active-limits at some moderate value (or the line inductance serves as adequate limiting), and the claim is simply that it was tested on a generator capable of 100k S/C.
Actually, 10us and a typical line inductance of say 100uH would be very reasonable (that's a mere ΔI = 40A), I doubt it does any active limiting at all.
I measured a similar waveform here, on the electronic fuse device, by switching in a 30V supply (of very low source resistance) while the fuse is active (on):
In the first microsecond, current rises to 120A (this is -20A/div equivalent scale). Active limiting kicks in and limits it to about 60A flat band, before shutting off. A small undershoot occurs as the stray inductance discharges into the TVS diode. This was with a mere 150mm twisted pair lead, or about as many nH. So you can see, inductance is very important on these time scales.
(The corresponding waveform for the switching limiter circuit is much less remarkable: there's a slight overshoot on the leading edge (due to response time), then there's a somewhat lumpy (switching ripple) flat square pulse about 150ms long, then it stops. :P )
Tim
jbb:
Maybe it’s a hybrid with a semiconductor stage to limit current and a mechanical disconnector to make it stay disconnected. I expect UL were quite thorough testing this one.
Let’s hope Big Clive gets his mitts on some of them :).
They could be very good news for DC installations. DC is hard to break but otherwise attractive for a lot of modern equipment (eg data centres) that have switch mode supplies in anyway.
Finally, I wouldn’t trust a purely semiconductor breaker to keep the circuit disconnected while I work on it...
Jeroen3:
--- Quote from: james_s on May 23, 2019, 09:07:06 pm ---Even with good protection the idea makes me nervous. In my experience, semiconductor devices almost always fail shorted, and they do fail occasionally even in the best most conservatively designed equipment. Electromechanical breakers on the other hand can fail shorted but it's rare enough that I've never personally encountered it, and once one is shut off it's virtually impossible for it to fail in such a way as to turn itself back on.
--- End quote ---
Somewhat larger circuit breakers are common to fail closed. The mechanism get jammed or it closed with a large inrush welding the contacts.
So yes, I've heard it's quite the experience arriving at a grid support genset where the breaker failed closed and the engine shut down. (hint: generator keeps running)
In your home or office installation the mechanical circuit breaker will never fail close since they are underrated. Sometimes an GFCI gets lazy and won't open, but that's due to the trip coil being jammed.
I can see some advantages of this system. You can configure them slightly below the mechanical breaker profile and remote monitor and intervene if needed. Since mechanical reclosers are big and expensive.
Navigation
[0] Message Index
[*] Previous page
Go to full version