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Timeline for Help with high-current DC switching

Current License: CC BY-SA 4.0

22 events
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Sep 30, 2020 at 11:58 answer added bobflux timeline score: 1
Sep 29, 2020 at 10:41 answer added David00 timeline score: 1
Sep 28, 2020 at 21:31 comment added David00 @Harper. Thanks for the suggestion. I've taken that approach many times in the past for 24 V designs - usually ending up with Finder 22 Series parts. But for 48 V there are few 240 V AC contactors with a suitable DC1 rating for 20 A - except around the £80+ mark. My "go-to" contactor for much higher currents is an Albright SW60 – which costs £26 - but it needs around 6W to energise the coil. For this particular application I'm looking for a 3W or less coil, something that a contactor in the middle ground between 20 A at 24V DC at 20 A at 60 V DC is likely to have.
Sep 28, 2020 at 20:05 comment added Harper - Reinstate Monica Look for AC mains contactors. Many of them have a DC rating. You're not going to find them in Arduino-tier hobby electronics, but they'll be in industrial electrician's kit e.g. sold by Grainger, Greybar, etc.
Sep 28, 2020 at 17:55 comment added David00 @Neil_UK I'm still open to a MOSFET solution, even if it's higher cost - can you suggest a design pls?
Sep 28, 2020 at 13:41 comment added David00 Reasonable price - sub £25.
Sep 28, 2020 at 13:41 comment added David00 Marcus, I didn't realise this was off topic until I saw your original post. That is what I meant... I understand you can't recommend a product. Do you perhaps know of any solution posted that might help? Again, I had looked for these before posting.
Sep 28, 2020 at 13:39 comment added Marcus Müller That was literally my first comment 22 minutes ago. And again, we're not in your head and don't know what "reasonable price" even means to you.
Sep 28, 2020 at 13:38 comment added David00 Hi Marcus, I'd looked thru Farnell, RS, Rapid, and others before posting. While there are many power relays with contacts rated for AC, I couldn't find any with DC contacts at a reasonable price. Farnell's own search just has a VAC filter for contacts, you can't search for relays with DC current rated contacts. Of course some power relays have AC rated contacts that also have a DC1 rating, but of the few I found they were £££. Hence why I asked if anyone could suggest their go-to solution. Didn't realise this was off-topic for the site.
Sep 28, 2020 at 13:34 review Close votes
Oct 9, 2020 at 3:04
Sep 28, 2020 at 13:29 comment added Marcus Müller @David00 you haven't even defined what your cost goals are, and it seems you haven't checked existing stock of the usual sources for components, and you're taking absolutely no action to make this question on-topic, but keep asking for product recommendations: voting to close as off-topic.
Sep 28, 2020 at 13:27 comment added David00 Hi Neil-UK, Thanks for the suggestion. I'm trying to reduce costs by using an off-the-shelf product. So while a MOSFET-based approach might work, it's likley to be a higher cost overall. Same for Thyristors or solid-state relays...
Sep 28, 2020 at 13:26 comment added Marcus Müller yes, plenty. Go look at the catalogues of the major electronics distributors.
Sep 28, 2020 at 13:24 comment added David00 Hi Marcus, I haven't come across any relays with contacts rated at 48V DC able to supply 15A. Do you know of any pls??
Sep 28, 2020 at 13:20 comment added Neil_UK Yup, 48 V DC is more than twice as difficult as 24 V DC. That's why they're a lot more expensive. If you want to design your own, you might think about MOSFETs, suitably protected against the inductive effects, to break the current.
Sep 28, 2020 at 13:19 comment added Marcus Müller Also, thinking about a way to convert this question into something that both helps you and is on-topic: You've described in a previous question that you know relays. A contactor is really only a relay-style device for high currents. 15 A DC isn't that much of a current; maybe you want to ask whether it's OK to use a relay rated for a fair bit more than 15 A and a fair bit more than 48 V as contactors in this application?
Sep 28, 2020 at 13:17 comment added Marcus Müller The unit "volt" is written "V", not "v". Please don't revert such changes.
Sep 28, 2020 at 13:17 history rollback Marcus Müller
Rollback to Revision 2
Sep 28, 2020 at 13:17 history edited David00 CC BY-SA 4.0
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Sep 28, 2020 at 13:16 comment added Marcus Müller Hi David! Sadly, you're asking specifically for a product recommendation, and those questions are specifically off-topic on this site.
Sep 28, 2020 at 13:15 history edited Marcus Müller CC BY-SA 4.0
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Sep 28, 2020 at 13:13 history asked David00 CC BY-SA 4.0