Need a current limiter/step down design.

I have way too much current going back to my DC power supply (6v/6a). I have a 4 ohm heating element that I need to keep up at max current. What could be used, minimally in parts, to bring down the amps to keep from killing/cooking my DC supply.
Cheers,
trooper

northendtrooper said:

I have way too much current going back to my DC power supply (6v/6a). I have a 4 ohm heating element that I need to keep up at max current. What could be used, minimally in parts, to bring down the amps to keep from killing/cooking my DC supply.
Cheers,
trooper

Click to expand...

Usually fuse is used to protect circuit from overcurrent.

In your case if you use 4R load this is 6V/4R=1,5A (1,5A of current).

1,5A is safe for your psu.

That heating element change resistance during heating ?

Additional power resistor can be added in serie with load to decrease current if needed.


Best regards,
Peter

tpetar said:

Usually fuse is used to protect circuit from overcurrent.

In your case if you use 4R load this is 6V/4R=1,5A (1,5A of current).

1,5A is safe for your psu.

That heating element change resistance during heating ?

Additional power resistor can be added in serie with load to decrease current if needed.


Best regards,
Peter

Click to expand...

The dimensions that I am using can't allow a fuse. The heating element is an inch of Nichrome so the changing of resistance is minimal. I am using AA batteries in series so if 1,5 is safe for the return without them melting then sweet! I haven't heard of a 4R load, could you teach me! Would that 4R keep from my Nichrome reaching maximum temperature?

northendtrooper said:

The dimensions that I am using can't allow a fuse. The heating element is an inch of Nichrome so the changing of resistance is minimal. I am using AA batteries in series so if 1,5 is safe for the return without them melting then sweet! I haven't heard of a 4R load, could you teach me! Would that 4R keep from my Nichrome reaching maximum temperature?

Click to expand...

There is small fuses in SMD cases.

I dont know can you get 1,5A for AA batteries, its sound very optimistic for that batteries. I supose that batteries are called "Die Hard". If you use them in serie you just increase voltage not current.


R is Ω

4R means 4Ω

If you want to decrese current more add additional resistor in circuit as I mention earlier.


Best regards,
Peter

tpetar said:

There is small fuses in SMD cases.

I dont know can you get 1,5A for AA batteries, its sound very optimistic for that batteries. I supose that batteries are called "Die Hard". If you use them in serie you just increase voltage not current.


R is Ω

4R means 4Ω

If you want to decrese current more add additional resistor in circuit as I mention earlier.


Best regards,
Peter

Click to expand...

Peter,
I just got back from doing some quick measurements. Excuse me that the resistance that I am looking at for my nichrome coil is .1-.4 ohms, yes it is very small. I have a stack of AA Duracell Copper Top batteries in series putting down 6v and 9amps. Each Copper top has the ability of 2+amps.
I need a circuit that will allow the nichrome to heat up to 800 degree (I did the math for this gauge and amps) and have a following circuit/chip to down the volts/amps back to the battery so it doesn't heat them up. Basically too much current/voltage back to the batteries. I am researching transformers, inverting amp, capacitors and inductors for my solution. I can't do much resistance because the low impedance of the nichrome.
I see what you mean by 4R, it has been a long time since I have talked electronic tech lingo so please bare with me.