Quiz

[Roff]

You have an electromagnet with lots of winding layers and lots of turns of wire. You hook it up to your 12 volt power supply, and find that it draws 1 amp. Your power supply can deliver 2 amps maximum. If you want to increase the strength of the electromagnet, should you add more turns or remove turns? Why?

 

[mstechca]

In my case, if the wire is supposed to be the same thickness and same material in every case, the wire should be shorter (less turns), because then there is more power delivered to the wires.

If I could use extra thick wire, I can make the turns even or add a few more turns.

To me, ohms law does the trick. After all, more current means more power.

 

[Someone Electro]

Add an extsactly same coil in parallel.

 

[mstechca]

I like that one.

How about get super thick wire and make hundreds of windings until it measures 2 amps, and then connect it.

 

[Someone Electro]

Puting 2 identical coils in parallel is the same as using twice as thick wire.

 

[Optikon]

You have an electromagnet with lots of winding layers and lots of turns of wire. You hook it up to your 12 volt power supply, and find that it draws 1 amp. Your power supply can deliver 2 amps maximum. If you want to increase the strength of the electromagnet, should you add more turns or remove turns? Why?

DC operation right?

To maximize electromagnet force, try to maximize B field.

B is proportional to N*I
N=total turns, I = current in those turns.

Must maximize N*I product.

I = (V/Rtot)
Rtot = 12Ohms from measurement.

IF each turn of wire only added R resistance, then maximizing turns would have the same effect on B as maximizing current. but since each turn gets progressivly larger in diameter (due to layering), The resistance of each turn grows (longer length) as you wind towards N turns. So Rtot is some nonlinear function of N. Rtot grows in magnitude larger than simply N*R


Any resistance represents an energy conversion to heat. That energy is not available for building up the B field which you are trying to increase.

Keep removing turns until you get the desired field strength or you reach Rtot = 6 Ohms.

 

[williB]

if your electro-maagnet only consumes 1A , when hooked up to 12 V , then your coil resistance is 12 ohms , i would remove half the coil , or till your resistance is 6 ohms..
i agree with opticon..

 

[chesart1]

You have an electromagnet with lots of winding layers and lots of turns of wire. You hook it up to your 12 volt power supply, and find that it draws 1 amp. Your power supply can deliver 2 amps maximum. If you want to increase the strength of the electromagnet, should you add more turns or remove turns? Why?

Add a core to your electromagnet

John

 

[akg]

You have an electromagnet with lots of winding layers and lots of turns of wire. You hook it up to your 12 volt power supply, and find that it draws 1 amp. Your power supply can deliver 2 amps maximum. If you want to increase the strength of the electromagnet, should you add more turns or remove turns? Why?

Add a core to your electromagnet

John

the Q was about this should you add more turns or remove turns? Why? not abt core

 

[Pommie]

As you want to maximise ampere turns, if you half the number of turns you will half the resistance (assuming single layer), this will double the current and so keep ampere turns the same.

The inverse will happen if you double the number of turns. This will make the whole thing more efficient and so would be the best bet. It'd run cooler as well.

However, if wound in multi layers as indicated and assuming that you can't add turns to the inside of the coil then reducing the turns would increase the strength. Although, if it's designed for 12V it will run extra hot.

And, if we could use a super conductor as the winding then just wind on as many turns as you can and reduce your current to a few milliamps.

Mike.

 

[Someone Electro]

A superconductor has no resistance so an infiite loehtg of this stuff would have 0 Ohm.