Analog switches

Projects General Guidance
1

Looking for some advice on analog switch specification. I have designed a circuit for current monitoring which works well, but it currently "only" lasts about two years. It has a current clamp so it would make sense to take power from that to charge a capacitor up, and then use the power every 10 minutes when a measurement is taken (and stored on sd).

So, I started out in a quest for a low power switch for double throw on two poles, where normally closed would connect the cap to the current clamp and parallel resistor, and when it is switched on by a 3.3v Atmel328p the current measurement could be taken whilst the power from the capacitor is being used.

After much Googling it seems like analog switches are the way to to, but choosing one seems bewildering! Are there any online resources which help specify what is required, or does anyone have any idea or experience on one which switches on 3.3v, is DPDT, can handle voltages up to maybe 6v (or could limit to 5v maybe), and uses very little power? In theory the circuit only uses 24mA, but charging could be up to 82.5mA rms by my calculations, so allow for 300mA to be safe?

2

using a CT to generate a voltage will offer power based on current being drawn. if the motor is off, or on low speed, the load may not be enough to deliver enough power to read and store on the SD card, if the CT is the only source

Drawing power from the CT to power your device is very useful, but if you have power lines, it goes that you have a direct source of power.

be that as it may, I would look at a PCB relay that has ratings in the sub 500mA range, maybe considder sub 100mA.
not sure of your CT or the max power. since the power line is protected by a circuit breaker, the amperage limit is fixed and you 'should' not get more than 80% of that if the device is selected properly.

as to your question, I would ask you post some links to data sheets of what you are looking at.