×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Induction plug design uses magnetic field to keep domestic wall plug in place

Induction plug design uses magnetic field to keep domestic wall plug in place

Induction plug design uses magnetic field to keep domestic wall plug in place

(OP)
Recent concept art for induction powered plugs to replace fixed plugs like the BS1363 proposed a feature which would lock the plug in place by passing a current through the socket area to create a magnetic field to keep it in place (much like a door lock) - I would like to know how feasible this would be for a loose plug?

There may be issues powering appliances through induction, but both are proven concepts, just not together as seen here:

https://www.behance.net/gallery/76410803/Ampere-Co...

What would be the challenges involved in bringing this to market, and how much would it cost do you think?

RE: Induction plug design uses magnetic field to keep domestic wall plug in place

Quote (OP)

...induction powered plugs to replace fixed plugs like the BS1363...

The product concept would seem to be designed to replace any given BS1363 socket, but as the inductive feature is intended for recharging little gadgets only, it's not a general replacement as implied by your choice of words. To make it clear, you'll still need normal 13A sockets to run your appliances such as TV and vacuum cleaner. Some of the images seem to show a parallel 13A socket, but it's not clear.

The magnetic lock mentions "reverses the magnet to release", which sounds like a pair of permanent magnets.

Using AC magnet (with an iron 'target') would be noisy, buzzing away with 50 or 60 Hz. Nobody would want that.

RE: Induction plug design uses magnetic field to keep domestic wall plug in place

They make it sound as if it were a consumer choice, but it's not. There are local statutes that require specific plus and sockets.

Given the amount of leech power we already consume, why would we want to add electromagnets to that?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Induction plug design uses magnetic field to keep domestic wall plug in place

Passing power via inductance is much less efficient then passing power via 2 contacts.

Keeping an inductive "plug" connected to an inductive "socket" via an electromagnet field is very inefficient when compare to the current plug and socket which uses no energy to keep connected.

Sure, the standard plugs and sockets can wear and become loose, but be honest about how much of an issue this really is. What percentage of plugs in service actually do wear out?

Something I have found very ironic for a long time now is the people who come up with ideas which involve adding a whole bunch of parasitic loads (in this case a load at every socket) to a dwelling to reduce the power usage by that dwelling.

RE: Induction plug design uses magnetic field to keep domestic wall plug in place

What about contact heating from higher contact resistance? Right now, your hand puts a energy into the action of plugging to spread springing contacts to ensure contact resistance is low.

What happens during a power failure? I can imagine it now - lights flicker followed by the sound of plugs hitting the floor all over the house.


RE: Induction plug design uses magnetic field to keep domestic wall plug in place

(OP)
VE1BLL : "Using AC magnet (with an iron 'target') would be noisy, buzzing away with 50 or 60 Hz. Nobody would want that." - I recall when magnetic doors are secure that they don't make any noise, possibly only when used to open them, so the plug could be attached all of the time without audible noise?

IRStuff : "Given the amount of leech power we already consume, why would we want to add electromagnets to that?" - Good point, I didn't think about the running costs, however keeping a plug in place would be possible with a magnet's normal attraction, the field would likely only be used for critical applications as these would be for low powered devices.

I think the best use case might be in wet environments like a kitchen or wash room. While the power consumption might be high for many kitchen appliances, the concept and practicality of it interests me the most as existing loads could be retrofitted.

Comcokid : "What happens during a power failure? I can imagine it now - lights flicker followed by the sound of plugs hitting the floor all over the house." - The internal magnets would still maintain contact, only the electrically generated field would be dropped (and the power supply), not the natural attraction from earth magnets.

RE: Induction plug design uses magnetic field to keep domestic wall plug in place

Additionally, wireless chargers have not achieved much beyond about 80% efficiency, as contrasted with conventional transformers that can achieve 98% efficiency. That means that every 5W of power is accompanied by a 1W loss in the inductive charger itself, hardly a green achievement. Potentially, you might gain back some efficiency if the concept replaces all the wall-warts, since the only problem I see is that wall-warts tend to not place nicely with each other on a power strip.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Induction plug design uses magnetic field to keep domestic wall plug in place

(OP)
I can't say that anything these days is taken seriously if it's considered "green" any more, that fad has been and gone. However, money is and will always be king, so people interested in this are looking at the potential of the product, not the cost, and so long as it doesn't cost too much (e.g. the cost of a magnetic lock on a secure door for one plug, then it shouldn't be too much of an issue.

The doors can work either way as I recall, although it's not advised in case of fire, but the current can be passed to open or close them, what about that system?

RE: Induction plug design uses magnetic field to keep domestic wall plug in place

Quote (k1acept)

...when magnetic doors are secure that they don't make any noise...

I believe that Magnetic Door Locks (of the sort typically installed at the top of the door) are generally powered with 12/24 volts, maybe an amp or less, of DC. Thus totally silent.

By way of comparison, those old fashioned near-comedy remote control door looks (of the sort installed in the door jamb next to the door knob) were AC powered and are the very origin of the phrase: "Can you buzz the door to let me in?"

RE: Induction plug design uses magnetic field to keep domestic wall plug in place

Ignoring the technical issues and going back to your first post;

Are you asking if a magnetic solution would help to keep a loose plug in a conventional socket? If yes, then no it would not help unless you come up with a magnetic way to squeeze the contacts in the socket together so they grip the plug contacts.

If you're asking about the feasability of a whole new style of plug like in the link then the following applies. #1 also somewhat applies to the above unless the solution for the above doesn't change the socket backwards compatibility.

1. A brand new style induction socket will be VERY difficult to bring to market. You are competing against a VERY established product that has been adapted by EVERYONE and is DIRT cheap.

You will have a very hard time convincing a majority of consumers to put these fancy expensive new induction outlets into their house only to also have to buy adapters that their appliances and such can plug into just to get them connected to their new wall outlet. Having that plug connection at the adapter also kills the whole point of the new outlet. Getting the electrical appliance manufacturers to build their 'things' with the new plug won't happen until there is enough demand which won't happen until there is an installed base.

2. The cost will be MUCH more than the dirt cheap outlets in use today. Electronics and such simply will be more expensive than 2 pieces of plastic and some metal bits. It's not possible to be price competitive between those 2 devices.


The biggest technical hurdle against an inductive plug was already pointed out. Even at 90% or 95% efficiency, you will be melting the plastic of the plug when trying to transfer the maximum power level possible from a 120V/15A North American outlet. Countries using 220-240V at their outlets will be more capable of melting the plastic.

The only way I see a whole new plug/socket standard gaining widespread use is via code. So, you'd basically have to convince the existing industry that the new way is so much better that it needs to be forced into use via legislation/code adaption. Good luck with that one.

RE: Induction plug design uses magnetic field to keep domestic wall plug in place

Quote (LionelHutz)

2. The cost will be MUCH more than the dirt cheap outlets in use today. Electronics and such simply will be more expensive than 2 pieces of plastic and some metal bits. It's not possible to be price competitive between those 2 devices.

Not to throw a monkey wrench into a reasonable argument, but... the wall sockets with integrated USB chargers sell quite well, and they're more than just a few bits of metal and plastic.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: Induction plug design uses magnetic field to keep domestic wall plug in place

(OP)
LionelHutz : Hi Lionel, and thank you for contributing to keeping this topic alive. My primary concern was with the technical feasibility of the concept design, rather than mass market potential. After reading that the concept was technically flawed I was intrigued to better understand why as I knew that all of the technologies worked separately, so why not together?

1. The wall outlet transfers power to the device's plug through induction.
2. With no need for physical patterned connectors any device could be powered: the parallel sockets would readily probe a device from Japan, as they would form the UK, and supply the appropriate voltage, polarity, AC/DC automatically.
3. A more permanent option to keep the plug in place with a magnetic field.

1. The issue of heat you mention is the issue facing the wireless power industry as demands increase for "fast chargers" and higher demanding loads so I read. I think I understand correctly that the losses with inefficiently directly translate into heat, especially with greater loads. However, as of 2011 I recall motor driven food blenders being powered (perhaps only pulsed?) with induction power from directly beneath a modified kitchen counter top. I understand distance to be a complication for induction, however if the plug's surface is directly flush with the wall outlet antenna to get the best possible alignment then could a food processor not be powered at any distance if tethered by a cable? Fundamentally, wireless power via induction does work safely for high demanding loads, so the concept design can surely power more demanding household appliances than just a low powered devices?

2. While universal plug adaptors exist, I believe they channel their supply based on a physical configuration. However, with more complex machinery such as a multimeter it is routine to check the polarity of a circuit for example, as well as other necessary checks to perform to know what conditions the device requires to safely power it. This is all added cost I agree: from the system to configure the power spat out from outlet automatically itself, to the information wirelessly transmitted of the configuration that the device(s) require to either an existing home network, or directly to a smart phone device (home automation) within range.

3. The option to firmly hold the plug in place at the wall outlet was hinted at as being ancillary to the initial attraction of existing magnets themselves. The convenience of neodymium magnets are likely enough with their strength directly pole-to-pole being their strongest, however sliding the surfaces away from each other is a lot less demanding and not ideal when vacuuming or using food related appliances. The idea then from the concept is to increase this with I assume a magnetic field, which makes sense as the wall outlet is in and of itself its own power supply! My research uncovered two options: one where the field was switched on, becoming a noisy parasitic load, or the opposite of which power would relieve the field, one of the two, but this seems to be the idea.


All of these technologies are real, just separately, what I want to know is what would need to be considered when putting them all together. Sound and heat issues seem to be apparent, as well as matters of efficiency and running cost compared to existing options - but, how to overcome these?

RE: Induction plug design uses magnetic field to keep domestic wall plug in place

The question is often not how, but why. Just because you can do something does not mean that you should.
> From what you describe, "With no need for physical patterned connectors any device could be powered" is not true; you would need adapters specially designed to transfer inductive power into a hard-wired socket, which would be more expensive than just a plastic and metal plug adapter.
> Moreover, while the wireless blender was a bit hit in 2013, it's still not for sale 6 years later. That's likely because the size/power/frequency of the inductive couple is insane for the amount of power one needs for a powerful blender. Getting 1 kW across a solid core transformer is one thing, but getting that across an air-gapped inductive couple is probably VERY challenging
> As pointed out in a few of the articles, you trade the convenience of wireless against reducing your counter space to 1 sq ft or less. And, unless you want to have multiple inductive access points and concomitant cost and complexity, you can't use more than one appliance at a time.
> Some of the claims on https://www.behance.net/gallery/76410803/Ampere-Co... are BS. We couldn't agree on actual hardware plugs, so why would we agree on wireless plugs? I don't see anything that makes it more suitable than existing power line hardware for power line ethernet.


TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Induction plug design uses magnetic field to keep domestic wall plug in place

Where are those blenders being sold and what percentage of blender sales do they account for?


MacGyverS2000 - similar question. What percentage of outlets sold have USB sockets in them. Trying to use that as a comparison point completely ignores the fact that USB equipped outlets provide a means to get power to an already well accepted standard plug that started life as a PC port, which helped tremendously in it gaining acceptance. If USB hadn't become a widely accepted PC standard then it'd be another dead technology. Is there a place like PC use where these power plugs could gain a foothold towards everyday use?

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources

eBook - Mastering Tolerances for Machined Parts
When making CNC machined parts, mastering tolerances can be challenging. Are general tolerances good enough? When does it make sense to call out for tighter tolerances? Do you need a better understanding of fits, datums, or GD&T? Learn about these topics and more in Xometry's new e-book. Download Now
eBook – How to Choose the Correct Corrosion Testing Method
When designing a metal component, engineers have to consider how susceptible certain alloys are to corrosion in the final product’s operating environment. In a recent study by NACE (National Association of Corrosion Engineers), it was estimated that the direct and indirect costs of corrosion in the United States is approximately 6.2% of the GDP. In 2016, that cost exceeded $1 trillion dollars for the first time. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close