Current limiting

ciupakabra

hi. question

i have DC power supply 42V and 6.3A. Constant current. and i can adjust voltage

but i need only 38V and 2.1 A

to prevent thermal runaway i need resistor.

would be ok this one?

PWR247T-100-2R00F - Current Sense Through Hole Resistor, 2 ohm, PWR247T-100 Series, 100 W, Thick Film, TO-247, ± 1%

by my knowledge it would limit current to ~2.5A and it is acceptable for me.

Calahonda52

Mods, move to elec

DublinDilbert

ciupakabra wrote: »

hi. question

i have DC power supply 42V and 6.3A. Constant current. and i can adjust voltage

but i need only 38V and 2.1 A

to prevent thermal runaway i need resistor.

would be ok this one?

PWR247T-100-2R00F - Current Sense Through Hole Resistor, 2 ohm, PWR247T-100 Series, 100 W, Thick Film, TO-247, ± 1%

by my knowledge it would limit current to ~2.5A and it is acceptable for me.

Well if its a 6.3A constant current power supply, that is giong to be what it will try to deliver. It will keep increasing its voltage till it reaches the max or delviers 6.3A. A resistor will not solve this problem.

Explain the problem, what load your trying to power etc... and people can advise. But a series resistor will not do what you need in this case. Also you'd require the resistor do dissipate a large amount of energy.

Steve

No offence intended but you need to consult with someone who understands electricity as you clearly do not - you risk causing a fire and harming others with what you are doing, seriously, talk to a pro.

ciupakabra wrote: »

hi. question

i have DC power supply 42V and 6.3A. Constant current. and i can adjust voltage

but i need only 38V and 2.1 A

to prevent thermal runaway i need resistor.

would be ok this one?

PWR247T-100-2R00F - Current Sense Through Hole Resistor, 2 ohm, PWR247T-100 Series, 100 W, Thick Film, TO-247, ± 1%

by my knowledge it would limit current to ~2.5A and it is acceptable for me.

delly

Moving thread to the electrical forum. Please be aware that the electrical forum rules now apply, inclusive of the relevant advice given in relation to safety protocols and procedures.

RandomUsername

ciupakabra wrote:

i have DC power supply 42V and 6.3A. Constant current. and i can adjust voltage

If it's constant current it should adjust the voltage not you. Post a pic if the data sticker/specs.

ciupakabra

its a constant current, constant voltage DC power supply. it has CC and CV control with potentiometers. but it will be running 3 parallel led`s stripes.
on each line i want to put resistor (what should put ~2.5A limit) and fuse ~2.5A.

im not stupid on electricity. working with arduino, have soldering skills, some experiance of finding and re-soldering blown capacitors.

but in this feeld have experience gaps. i would like to be sure if it is possible at all

i want to achieve that if one led become dead other will become intact or just auto disconnected from line

DublinDilbert

Still not sure what your looking to do. Are you trying to run 3 strips of LEDs in parallel? Do you want them all on at the same time? or do you want one to light up if another strip fails?

A 2 ohm resistor will drop 4v when there is 2 amps flowing.