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PSU question

PostPosted: Sat Dec 06, 2008 4:12 am
by T1MT1M
Question for anyone with a phd in physics or nick :P.


When people wrap their cords around each other and twist them with a PSU, wouldn't this create an electromagnet??

and if so or not so then why?

Re: PSU question

PostPosted: Sat Dec 06, 2008 9:11 am
by Slotback
In order to concentrate the magnetic field generated by a wire, it is commonly wound into a coil, where many turns of wire sit side by side. The magnetic field of all the turns of wire passes through the center of the coil. A coil forming the shape of a straight tube, a helix (similar to a corkscrew) is called a solenoid; a solenoid that is bent into a donut shape so that the ends meet is a toroid. Much stronger magnetic fields can be produced if a "core" of ferromagnetic material, such as soft iron, is placed inside the coil. The core magnifies the magnetic field to thousands of times the strength of the field of the coil alone. This is called a ferromagnetic-core or iron-core electromagnet.

http://en.wikipedia.org/wiki/Electromagnet


So I guess it does create a magnetic field, just not a strong one.

Re: PSU question

PostPosted: Sat Dec 06, 2008 10:34 am
by NickN
You

Re: PSU question

PostPosted: Sun Dec 07, 2008 10:53 am
by Brett_Henderson
This brings back fun memories  :D

When CPUs were first breaking the 100Mghz, through the time that a 333Mghz Pentium was was coming out...  M/B designers were facing the first, real hurdle in noise control. Heck.. at those amazing frequencies, pc-board conductors themsevles become capacitors.. and a complex curve in those conductors can become an inductor. Remember amateur radio 2-meter band ? 150Mghz +/- and a pipe bent into a 'J' can be an inductive load (antenna).

One appraoch to this, was to try to design noise filtering capacitors/inductors  INTO the board. Take advantage of this phenom, rather than fight it.

ANYway... clock speeds have gotten so fast that now it's like worrying about cell phones interfering with AM radio  ::).. and things like solid-state capacitors have make filtering circuits rock-stable with tiny band-pass capability..

Insightful question, none-the-less..

Re: PSU question

PostPosted: Sun Dec 07, 2008 5:19 pm
by Fozzer
Question for anyone with a phd in physics or nick :P.


When people wrap their cords around each other and twist them with a PSU, wouldn't this create an electromagnet??

and if so or not so then why?


The majority of

Re: PSU question

PostPosted: Mon Dec 08, 2008 4:26 am
by T1MT1M

You[ch8217]re diving into areas which have outcomes based on each given circumstance however the field potential created in coiling as described is not going to overcome the noise clamping circuits of the devices.

In the case of a PSU there is not enough wire or core element to create any kind of strong field

all living things emit an electrical signal too

sharks have the ability to sense that emission at a distance





Yeah thats true becaue the reason why i ask is because we have only ever had one situation of this every going wrong (with the wires wrapped and twisted) but at the shop the one time we have had one like that in it all the wired coming out of the PSU were screwed and melted together lol.

Re: PSU question

PostPosted: Mon Dec 08, 2008 8:32 am
by NickN
Question for anyone with a phd in physics or nick :P.


When people wrap their cords around each other and twist them with a PSU, wouldn't this create an electromagnet??

and if so or not so then why?


The majority of

Re: PSU question

PostPosted: Mon Dec 08, 2008 8:33 am
by NickN
[quote][quote]

You

Re: PSU question

PostPosted: Mon Dec 08, 2008 8:38 am
by T1MT1M

You[ch8217]re diving into areas which have outcomes based on each given circumstance however the field potential created in coiling as described is not going to overcome the noise clamping circuits of the devices.

In the case of a PSU there is not enough wire or core element to create any kind of strong field

all living things emit an electrical signal too

sharks have the ability to sense that emission at a distance





Yeah thats true becaue the reason why i ask is because we have only ever had one situation of this every going wrong (with the wires wrapped and twisted) but at the shop the one time we have had one like that in it all the wired coming out of the PSU were screwed and melted together lol.



that was not a magnetic field that caused a meltdown... that was someone pulling more power from the PSU than they should have... and/or a defective unit


Yeah thats what i thought but i just agreed with the other guys to make them feel special :P. I was just commenting on the ratio of good vs bad PSU's that have come from the twisted wires. so for it beats it by 100% :P. But i think his agrument would be that he thinks it was the magnetic field that caused something to go wrong in the first place.

Re: PSU question

PostPosted: Mon Dec 08, 2008 4:46 pm
by drummer_tom
Yes it will create an electromagnet. Is it worth worrying about? Not with the little amount of power there is.

One of my hobbies is stage lighting and when I was first starting out I made this mistake. I wrapped a wire which had 2 x 1000w lights on the end very tightly and closely around the lighting bar in the ceiling. However I was explained why this wasn't such a good idea and learned from the experience.

True story!