Current limiter circuit and Electromagnet

[MrOzil]

Hi im new in this forum and im about to design an electromagnet to pick up coins. As i know the coil will gets hot when current flows.

The battery that will be use is 4x1.5V size AA.

My question is,

- Do i need a current limiting circuit to avoid the coil from getting hot ?

- What other ways can i do to overcome the coil from getting hot as long it can produce good magnetic strength ?


Thanks...

 

[Grossel]

Use a thin cobber wire so that you get enough resistance. Or make it physically big so that it doesn't get hot (I'm not saying that it won't drain your batteries).

Unless you're using PWM to control the magnet, a current limiter circuit will drain the batteries fast and the effiency will be poor.

 

[shortbus=]

What kind of "coins"? Didn't know anyone still used steel or iron for coinage.

 

[MrOzil]

So you're saying that using current limiter circuit for my application is not recommended ?

 

[Nigel Goodwin]

So you're saying that using current limiter circuit for my application is not recommended ?

No point with 4xAA's - limiting the current would simply make the magnet weaker. As suggested, wind the coil using suitably thin wire to give the correct result you want, this will give maximum efficiency, but it will run hot.

 

[MrOzil]

it is a copper plated steel....

 

[MrOzil]

Will it makes the battery weaker if the electromagnet switched on for couple of minutes ?....the coin need to be lift up from one point to the other....plus there are some circuits associated in the robot and 5V DC battery is the only main supply.

 

[Nigel Goodwin]

Will it makes the battery weaker if the electromagnet switched on for couple of minutes ?....the coin need to be lift up from one point to the other....plus there are some circuits associated in the robot and 5V DC battery is the only main supply.

Again it depends how strong you want the magnet - winding it with lot's more turns of thinner wire will reduce power consumption, but will make it weaker. I suggest you try various different windings to find what works best.

 

[MrOzil]

Ok...we will try winding it with different magnet wires...another thing is...

Do i need a 'snubber' to avoid the voltage spike due to the inductance when switch off for my DC power electromagnet ?

Im thinking to connect a relay to perform on off of the electromagnet....Is this ok ?

This is because i need separate DC supply for the electromagnet to works..