Switch ratings

[Sean Mathias]

I have a 3 position rotary switch that is rated for 4A-125VAC and
2A-250VAC. From this, is it reasonable to extrapolate that it would
be suitable for 16A-30VAC?

Doubling the voltage halves the current (Ohm's law), should I expect
this to work in reverse, or might the switch be rated for a maximum of
4A?

Sean

 

[Peter A Forbes]

On Mon, 17 May 2004 09:01:30 -0700, Sean Mathias <seanm@prosolve.com> wrote:

I have a 3 position rotary switch that is rated for 4A-125VAC and
2A-250VAC. From this, is it reasonable to extrapolate that it would
be suitable for 16A-30VAC?

Doubling the voltage halves the current (Ohm's law), should I expect
this to work in reverse, or might the switch be rated for a maximum of
4A?

Sean

The dual ratings are for world-wide type approvals, but the switch would not be
rated for high current, although the voltage would obviously be OK. 4A is the
maximum.

Switches are rated for breaking and carrying current mainly, the effect of the
contact erosion through arcing is the major factor in lifing the switch. The
construction of the switch would determine its maximum current carrying
capacity.

DC is a different can of worms, we are just sourcing switches for 750V DC at
150A, they have large arc-chutes and magnetic blow-outs to suppress the rather
large arcs that get drawn when breaking a load.

Peter

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diesel@easynet.co.uk
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