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Author Topic: How Strong Is This Magnetic Lock ?  (Read 16593 times)

Offline neilep

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How Strong Is This Magnetic Lock ?
« on: 06/08/2010 09:28:02 »
Dearest magnetologists,

As a sheepy I of course luff magnets !..From the moment I awake all I ever do is think about magents and magnet related joyness !...yep magnets are just like...well great !!

So, ewe can imagine my sheer climatic pleasure when I came across this magentic door holder thingy at 2:30am this morning.



A Magnetic Door Lock Thingy To Die For !


Now as far as magnetic door lock thingys this one s a real babe !..A real thing of beauty...oh yes indeed !!

The disc itself is only about 2.5 inches in diameter and yet it grips the door so strong that it just will not budge unless I release it with the red button ! For your convenience I have labelled the red button in red so that the easily confused will not be easily confused.


What i would like to know is how strong is that electro magnet ?..how strong does it neeed to be to grip this door  ? ...(and it 's a BIG firedoor).There was no way I could even make it budge even the slightest !!!............I realise I can't give ewe the tech specs but you're bog standard guestimatable answers would be most helpful.

I have four days off now..I won't be seeing that door now till next Tuesday !..oh woe is me !



Hugs & shmishes


mwah mwah mwah


neil
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« Last Edit: 07/06/2011 09:56:41 by imatfaal »


 

Offline RD

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Re: How Strong Is This Magnetic Lock ?
« Reply #1 on: 06/08/2010 11:20:52 »
From this supplier they are available from 200N to 1200N strengths ...

Quote
These robust encapsulated electromagnetic door holders have a door holding force of 120kg (1200N)

http://www.geofire.co.uk/
« Last Edit: 06/08/2010 11:25:15 by RD »
 

Offline imatfaal

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Re: How Strong Is This Magnetic Lock ?
« Reply #2 on: 09/08/2010 12:23:58 »
I am surprised they are so low - so if you could get any purchase for a lever or a couple of big blokes you could pop it.  I presume they also have a remote release, other than the red button, otherwise what would be the point? A decent bolt or bar would be far more secure.

 

Offline peppercorn

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Re: How Strong Is This Magnetic Lock ?
« Reply #3 on: 09/08/2010 13:23:18 »
I observe this is a fire door, but what happens if the power goes off?  Is it then unlocked? - potentially this could put sheepy at risk of sheep rustlers!  [:-'(]
 

Offline SeanB

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Re: How Strong Is This Magnetic Lock ?
« Reply #4 on: 09/08/2010 13:52:24 »
The idea behind those is that they hold the door open until either there is a fire, when the alarm will release them, or the power fails, which also releases them. The small locks like that are designed to "fail safe" in that almost any failure causes the door to be closed. They are low force, as all they have to do is hold the door open against accidental bumping, and to consume low power whilst doing so.

Much bigger ones are used on access control systems to keep doors closed, and are capable of resisting a lot more force, generally the lock selected is stronger than the door, as the door or the frame will break under attack long before the lock releases due to force applied. A weakness of these locks is that you need to close the 2 parts with precise alignment, as they will not operate with even the smallest of gaps, and any object between the plates seriously reduces holding force.

An alternate that is "fail secure" has a magnet (generally a big ferrite magnet) providing the holding power, with the coil being used to oppose the field and allow it to be released. These are a lot rarer, and generally are used inside bank vault doors to retain the inner low security door during the day.
 

Offline imatfaal

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Re: How Strong Is This Magnetic Lock ?
« Reply #5 on: 09/08/2010 14:45:22 »
SeanB - thanks; understanding arrives. I hadn't realised these held the doors open ...
 

Offline Bored chemist

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Re: How Strong Is This Magnetic Lock ?
« Reply #6 on: 09/08/2010 19:37:18 »
I am surprised they are so low - so if you could get any purchase for a lever or a couple of big blokes you could pop it.  I presume they also have a remote release, other than the red button, otherwise what would be the point? A decent bolt or bar would be far more secure.


Since, as has been said, these are not a security feature, it doesn't matter but I haven't seen many doors that a couple of strong blokes with crowbars couldn't get through.
 

Offline SeanB

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Re: How Strong Is This Magnetic Lock ?
« Reply #7 on: 09/08/2010 20:04:46 »
I worked in a building where we one night had a vehicle drive into our main gate at high speed. Result was a gate with scratched paint , a very short vehicle and a dead driver and passenger, both very drunk just before being very dead. You would need a little more than a crowbar to open that gate, it was designed to survive a truck impact.

As to the magnetic locks, they are very common as access controls to buildings, whist the fire door controls shown by the Sheepie are mostly used internally for corridors that should only be closed to prevent the spread of fire or smoke, and these are designed for low force and low power consumption. They are likely to be on for years at a time, and generally are powered by a fire panel with a limited battery capacity and a requirement dictated by the fireproof cable for a low power consumption as it is generally mounted at the end of a really long cable that has limited current ratings.
 

Offline Mazurka

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Re: How Strong Is This Magnetic Lock ?
« Reply #8 on: 10/08/2010 16:17:53 »
Didn't that Greek chap, which legend has it had a penchant for baths and running down the street naked, say something along the lines of "Give me a place to stand and with a lever I will move the whole world" ;) 
 

Offline Geezer

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Re: How Strong Is This Magnetic Lock ?
« Reply #9 on: 10/08/2010 19:40:30 »
Didn't that Greek chap, which legend has it had a penchant for baths and running down the street naked, say something along the lines of "Give me a place to stand and with a lever I will move the whole world"

I didn't know General Custer was Greek. See, you learn something new every day on TNS.
 

Offline FuzzyUK

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Re: How Strong Is This Magnetic Lock ?
« Reply #10 on: 18/08/2010 08:00:30 »
Dearest magnetologists,

As a sheepy I of course luff magnets !..From the moment I awake all I ever do is think about magents and magnet related joyness !...yep magnets are just like...well great !!

Dear sheepy,

Your obsession with magnets leads me to conclude you have a magnetic personality. Reduce your intake from two teaspoons of iron filings a day to just one.
 

Offline John09

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Re: How Strong Is This Magnetic Lock ?
« Reply #11 on: 20/08/2010 09:21:24 »
The things mentioned are unanimous and needs to be appreciated by everyone.
 

Offline jeffrojas2010

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Re: How Strong Is This Magnetic Lock ?
« Reply #12 on: 02/09/2010 09:16:47 »
hi , i am curious , my workplace is using magnetic + mechanical lock together .

I heard from the security guy that the magnetic lock is good enough to replace the mechanical lock , and that you need 600 pound of force to break it .

i am wondering , is it true that they are that strong ? considering i can push and see the door move to a gap of say 3 CM at the bottom . the top didnt budge cause the magnetic lock is on the top of the door .

so how good is it in security ? the guy tell me they could use whole magnetic lock for the place in fact without security lapse and in the event of power trip , the battery would kick in and last at least 8 Hours .

this aside , are they that strong ?
 

Offline Old Snowdrop

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Re: How Strong Is This Magnetic Lock ?
« Reply #13 on: 06/06/2011 15:22:20 »
Hi, 600lb breaking strain doors are used for internal doors. External doors would be 1200lb. The door frame would give up before the magnet. It is possible to 'pop' a smaller magnet.
 

Offline CliffordK

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Re: How Strong Is This Magnetic Lock ?
« Reply #14 on: 06/06/2011 22:17:44 »
There was keyed magnetic lock in a building where I used to work.  It seemed pretty stout.  I was told that it had an IR sensor on the inside, so I always wondered if the mechanism could be defeated by pouring a bucket of warm water under the door, but never tested it.

Remember, you can have the best retina scanners or keycard access...  that is only as good as the weakest link in the entire system.
 

Offline techmind

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How Strong Is This Magnetic Lock ?
« Reply #15 on: 12/06/2011 15:48:08 »
There was keyed magnetic lock in a building where I used to work.  It seemed pretty stout.  I was told that it had an IR sensor on the inside, so I always wondered if the mechanism could be defeated by pouring a bucket of warm water under the door, but never tested it.

Remember, you can have the best retina scanners or keycard access...  that is only as good as the weakest link in the entire system.

I think you're implying there's a trivial means of releasing the door from the inside to get out even though it requires some kind of 'access control' to gain entry from the outside. This is a common situation and sometimes some lateral (and maybe scientific) thinking yeilds some surprisingly easy ways this could be exploited to circumvent the system without using force...
 

Offline FuzzyUK

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How Strong Is This Magnetic Lock ?
« Reply #16 on: 15/06/2011 01:24:03 »
As a sheepy I of course luff magnets !..From the moment I awake all I ever do is think about magents and magnet related joyness !...yep magnets are just like...well great !!

It seems like you have an intense magnetic personality which unfortunately cannot be cured.
 

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How Strong Is This Magnetic Lock ?
« Reply #16 on: 15/06/2011 01:24:03 »

 

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