Model Boat Mayhem

Technical, Techniques, Hints, and Tips => The "Black Arts!" ( Electrics & Electronics ) => Topic started by: boatmadman on October 30, 2008, 03:40:14 pm

Title: Magnetism
Post by: boatmadman on October 30, 2008, 03:40:14 pm
This is directed at FLJ - (not because of his magnetic personality), but I thought I would post it here because it may be of general interest.

Dave, Are your gizmo's (particularly esc's and switchers) affected by magnetism? I ask because I am thinking of using neodym magnets to hold the superstructure in place on my current build, and there are 5 of your gizmo's plus a multichannel rx very close by.

Before anyone asks, no, I cant move the gizmo's somewhere else, as will become clear when I post pics.


Title: Re: Magnetism
Post by: FullLeatherJacket on October 30, 2008, 06:39:01 pm

Cast your mind back to school, and you might recall the theory. If you move a coil of wire through a magnetic field then a current is generated in it, and if you pass a current through a coil then you will generate a magnetic field around it. In other words (here it comes.....) magnets are like MP's; they don't do a damn thing until you kick 'em   ;)

I happily use strong magnets to hold down the S/S on both my Shamrock and Sentinel. I doubt if your classier neodym thingies produce a magnetic field much different from my cheapo door catches, so go for it, good buddy.

BTW don't you work at a power station..........................??   %)

Title: Re: Magnetism
Post by: boatmadman on October 30, 2008, 07:16:11 pm
Thanks Dave, and yes, I do work at a power station, but I am mechanical, ellectrikkery is white mans magic!  :-))
Title: Re: Magnetism
Post by: malcolmfrary on October 31, 2008, 11:02:12 am
To produce an electrical effect, the magnet and object need to be moving with respect to each other.  Once the superstructure is in place, the magnetic circuit should be closed, with virtually no external field. 
The only things that could be affected are relays, which might show a tendency to stick operated, but even this is highly unlikely as the relay would have to be in exactly the right position, i.e. VERY close to the magnet.
Title: Re: Magnetism
Post by: sweeper on October 31, 2008, 11:43:21 am
As stated above, you should only get a minimal fringe field from your magnets.
If however you are concerned about the effects after a trial, why not consider making a close fitting metallic screen around each of the magnets. In effect, a Farraday Cage? In industry the idea is used in instruments to protect them from stray magnetic fields and eliminate errors caused by the fields acting on the instrument movement.
Title: Re: Magnetism
Post by: Roger in France on October 31, 2008, 11:56:41 am
I have frequently used quite large, strong neodym magnets to secure hatches etc. without any ill effect on the performance of the gear on board.

Roger in France