I'm planning to use the following normally on push-button switch: http://uk.rs-online.com/web/p/push-button-switches/1336473/
According to the following data-sheet: http://uk.rs-online.com/webdocs/137f/0900766b8137f3b1.pdf it says:
Contact Current Rating: 650 mA @ 30 V dc
But in my application the button will be pushed less than a second where the voltage across it will be 48V and the current through it will be 48mA for less than a second.
Should I look at the power (P = I*V = 30*0.65) in this case, or I shouldn't use it since it says 30V in its ratings?
Edit:
Push-button controls 48V supply and is normally open. Here is the part of the circuit where the switch is in LTspice(I didn't check this in scope):
Points A and B represents the terminals of the push-button.
Below green plot is the potential difference across the switch terminals A and B:
And the blue plot below is the current through the switch:
And finally, I zoom to see both the voltage across the switch and the current through the switch:
What I understand from the above plots, the switch is exposed to 48V whenever it remains open. The moment the switch is closed, the potential difference drops quickly in nano-seconds to zero volts and micro-ampere level current passes through it.
What I understand from the first answeers is that, the problem with the following push button: http://uk.rs-online.com/webdocs/137f/0900766b8137f3b1.pdf is that if I use them in my circuit, they will be exposed to 48V all the time when the switch is normally open. So the real problem does not occur the moment I push the button but it occurs when the push button is not pushed at all.
Is that correct?
Best Answer
Arcing distance is determined by the voltage. Since the voltage in use is higher than the rating, either the switch may become damaged over time due to the contacts either eroding away or welding closed, or opening the switch may not reliably break the connection since arcing will occur.