DC Shunt Heat Dissipation..

[JohnnyRingo]

Anybody got a table of some sort with a general rule of thumb for heat loss on DC Shunts. The manufacturer of the ones we've ordered doesnt seem to have got that info!?!?

range 0-100A, 60mV output

cheers guys

 

[busbar]

Doesn’t 100A · 0.060V = 6W still work?

 

[JohnnyRingo]

no really because thats electrical power. only a percentage of that would be heat, surely?

 

[ScottyUK]

Yes, honestly, your shunt is dissipating 6W as heat. A shunt can't perform any mechanical work; what else could it dissipate the energy as?

Your shunt is just a resistor, much the same as an electric fire element or a tungsten lamp. The only difference is that the resistance is very small and the volt-drop is therefore small. Ohm's Law still applies.

P = V * I

or

P = I^2 * R

Both give the same result - 6 watts.



------------------------------

If we learn from our mistakes,
I'm getting a great education!

 

[JohnnyRingo]

Sorry about that busbar,
just after your post i spoke to somebody who imformed me the same..

cheers lads

 

[buzzp]

Busbar and ScottyUK are correct, all that power is dissipated as heat.

 

[busbar]

No problem, JR. The informal nature of Eng-Tips is handy for that reason.