arc-zero connector - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: June 03, 2024, 09:50:32 pm
content: I found this odd device.https://www.phoenixcontact.com/en-pc/events-and-news/news/safe-dc-connector-with-arc-zero-technologyI am suspicious about it, but it does seem like a good way to deal with PV without tarps and other shit like that. Would I feel better if there was a aluminum sheet taped over it with some good duct tape though?.... or some kind of deploy-able shroud, like windows blinds or Japanese 'stick' art or whatever its called that you can roll upand I don't like how close the electronics is to a potentially over heating connector, if its dirty or something. Since its a power interconnect with electronics on it, it seems to be at risk. Maybe I would make mine like a T shape with the electronics slightly away from the interconnect area that has the potential for over heating. If a component blows up it can damage the case and expose conductor, it would have to melt reaally bad to do that

author: Whales
author_rank: Super Contributor
timestamp: June 04, 2024, 12:36:09 am
content: I want to know what the circuit is. I wouldn't buy a safety device without knowing its method of operation.EDIT: Maybe it temporarily shorts the connector, which should be fine for solar panels. But how does it sense the problem scenario?Mechanical interlock to detect the inserted connector + current sensor? Maybe a reed switch to avoid water, but those can go bad/intermittent. If they put a micro in there to get consistent behaviour they'd open another bag of worms RE power supply.RF arc detect? I wonder if you could trip it through other means like arcselsewherein the system. If a panel is arcing then shorting it might even make the arc worse and fire more likely?

author: f4eru
author_rank: Super Contributor
timestamp: June 04, 2024, 05:46:28 pm
content: https://www.google.com/search?q=arc+connector+patent+phoenixnot sure if present in patents,..

author: coppercone2
author_rank: Super Contributor
timestamp: June 05, 2024, 12:42:19 am
content: this one has a mechanical sequencer with PTC's .https://patents.google.com/patent/KR100922694B1/enI personally think PTC break often, but I suppose that is because of the power grid. Since the connector is infrequently used, maybe its robust enough. It should only be engaged during disconnect, meaning maybe a handful of times if trouble shooting.but the picture clearly shows many partsThis has big-clives name on it. its like the perfect thing for him to review lol

author: Whales
author_rank: Super Contributor
timestamp: June 06, 2024, 03:01:54 am
content: Quote from: f4eru on June 04, 2024, 05:46:28 pmAlready had a look, couldn't find anything obvious. There are some solar connector patents but unrelated physical designs with no magic disconnect circuitry.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 06, 2024, 05:29:45 am
content: If it's not patentable (assumption), it might be as simple/dumb as an RC snubber, making contact before the main contacts do. Wouldn't really quench arcing in all cases (you could pull it apart slowly enough to still break down), but maybe along with a mechanical solution (over-center cam style snap-action?) the contacts normally open fast enough that it is very likely to work.Tim

author: coppercone2
author_rank: Super Contributor
timestamp: June 06, 2024, 10:19:47 am
content: that also means its possibly likely to start a problem when you reconnect it after assuming its safe rather then guaranteeing it.I think they have to think that its almost impossible for it not to work because it seems the risk of a bad contact causing heating is not worth the convenience of hot swap for something on a tar roof etc

author: Berni
author_rank: Super Contributor
timestamp: June 06, 2024, 11:08:25 am
content: This does not guard against a high resistance bad contact!The point of this connector is that it allows you to safely disconnect it while under load.Problem with PV installations is that they are high voltage DC systems. So you might have 1000V at 30A traveling trough one of these connectors along the series string of solar panels. The panels don't have On/Off switches on them and neither does the Sun. So maintenance is performed with wires still being energized (unless you have distributed MPPT optimizers on your panels). So if you try to unplug one of these connectors while 30A DC is flowing trough them you will end up drawing out a very hot white arc for a few centimeters. This arc can melt contacts, connectors, or jump to your hand and electrocute you. So the golden rule is DO NOT unplug under load (The inverter is supposed to be shutdown to drop the load to zero before you disconnect stuff).So id say what this connector does is likely have a 2nd set of contacts inside. So this way when you pull the connector apart it first connects a PTC resistor across the contacts, so that when contacts disconnect the current moves over onto the PTC where it rapidly gets hot, so the resistance shoots up and this gradually drops the current down to near 0A, then as you keep pulling the connector apart the PTC also looses contact, but because the current is near 0 means that no arc is formed, so the connector is undamaged and the maintenance worker is still alive.