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A random science question...

Posted: Sun Jun 24, 2007 12:00 am
by jtaylor
We have a number of radios which we use for communication on our production floor at work.
These are rechargable.
It's been found that if the chargers are placed in a metal filing cabinet, and the radios then placed in the charging units, they do not charge properly....
Place them on a bench, and they charge no problem....

This seems very weird to me....any scientists out there possit an explanation?

J

Re: A random science question...

Posted: Sun Jun 24, 2007 2:23 am
by icomefromalanddownunder
jtaylor wrote:We have a number of radios which we use for communication on our production floor at work.
These are rechargable.
It's been found that if the chargers are placed in a metal filing cabinet, and the radios then placed in the charging units, they do not charge properly....
Place them on a bench, and they charge no problem....

This seems very weird to me....any scientists out there possit an explanation?

J
It's the shape of the filing cabinets which is causing the problem. If you place the radios inside a pyramid you won't even need the charger :wink:

Posted: Sun Jun 24, 2007 8:32 am
by J.R.
No point on charging them on a bus, though...........................










Busses never seem to have...........





















a good conductor !
:oops: :lol: :oops: :lol: :oops:

Posted: Sun Jun 24, 2007 10:44 am
by englishangel
We have/had* rechargeable batteries at wotk for the camera. I wonder if that was why they would only hold sufficient charge to take about 12 photos.

*We now have a new camera which a wotsit ion battery.

Re: A random science question...

Posted: Sun Jun 24, 2007 11:47 am
by AndrewH
jtaylor wrote:We have a number of radios which we use for communication on our production floor at work.
These are rechargable.
It's been found that if the chargers are placed in a metal filing cabinet, and the radios then placed in the charging units, they do not charge properly....
Place them on a bench, and they charge no problem....

This seems very weird to me....any scientists out there possit an explanation?

J
The steel of the filing cabinet is becoming part of the magnetic circuit of the charger, the details will depend on the charger. If it is like my electric toothbrush (no electrical contacts), the charger and toothbrush each have half a transformer that connect (magnetically) when the toothbrush is in the charger. Even if there are normal electrical contacts between the radio and the charger the charger will have some form of transformer (exactly what depends on design) to convert from AC supply voltage to low voltage, in this case a well designed unit should not be effected by exteranal filing cabinets but a lot of these units are designed down to a price!

Do you get slight electric shocks from the filing cabinets (when the chargers & radios are in them)?

Posted: Mon Jul 09, 2007 12:56 pm
by wurzel
I think the cabinet is acting as a faraday cage

Posted: Mon Jul 09, 2007 1:31 pm
by J.R.
They used to have a lovely faraday at London Zoo.

That was in a cage as well !! :oops:

(where's me coat ?)