current limiter circuit

[refigh]

hi,
I need a series current limiter circuit. the characteristic which I
need is that circuit has very low resistance and also limit the
current from going too high,
I want to use it as current protect for a circuit.
I don want to use fuse because it broken in high current. I also dont
want to feed back from any other point of circuit so I can use
something like switch.

 

[Rich Grise]

refigh wrote:

I need a series current limiter circuit. the characteristic which I
need is that circuit has very low resistance and also limit the
current from going too high,
I want to use it as current protect for a circuit.
I don want to use fuse because it broken in high current. I also dont
want to feed back from any other point of circuit so I can use
something like switch.

Here's a start:
http://www.mouser.com/Search/Refine.aspx?Keyword=current+regulator+diodes

Have Fun!
Rich

 

[Phil Allison]

"refigh"

hi,
I need a series current limiter circuit. the characteristic which I
need is that circuit has very low resistance and also limit the
current from going too high,
I want to use it as current protect for a circuit.
I don want to use fuse because it broken in high current. I also dont
want to feed back from any other point of circuit so I can use
something like switch.

** This might be what you need.

http://www.littelfuse.com/resettable-ptcs.html

Don't be afraid to give us the details of what you are doing.

Get much better advice that way.



..... Phil

 

[refigh]

On Jul 5, 9:12 am, Rich Grise <ri...@example.net.invalid> wrote:

refigh wrote:
I need a series current limiter circuit. the characteristic which I
need is that circuit has very low resistance and also limit the
current from going too high,
I want to use it as current protect for a circuit.
I don want to use fuse because it broken in high current. I also dont
want to feed back from any other point of circuit so I can use
something like switch.

Here's a start:http://www.mouser.com/Search/Refine.aspx?Keyword=current+regulator+di...

Have Fun!
Rich

thanks it is so interesting !

 

[Rich Grise]

refigh wrote:

On Jul 5, 9:12 am, Rich Grise <ri...@example.net.invalid> wrote:
refigh wrote:
I need a series current limiter circuit. the characteristic which I
need is that circuit has very low resistance and also limit the
current from going too high,
I want to use it as current protect for a circuit.
I don want to use fuse because it broken in high current. I also dont
want to feed back from any other point of circuit so I can use
something like switch.

Here's a

start:http://www.mouser.com/Search/Refine.aspx?Keyword=current+regulator+di...

thanks it is so interesting !

I'm glad you enjoy it - do google (or lycos, or yahoo, or any convenient
search engine) on any electronic term while adding "tutorial" to the search
string.

And Welcome to the Loony Bin! ;-D

Cheers!
Rich

 

[John Fields]

On Mon, 4 Jul 2011 22:02:21 -0700 (PDT), refigh <hamze60@gmail.com>
wrote:

hi,
I need a series current limiter circuit. the characteristic which I
need is that circuit has very low resistance and also limit the
current from going too high,

---
The resistance of the limiter will depend on the voltage across the
source, the voltage across the load, and the current through the load.

It cannot, therefore, be arbitrarily specified, since it will be what
it will be,
---

I want to use it as current protect for a circuit.
I don want to use fuse because it broken in high current. I also dont
want to feed back from any other point of circuit so I can use
something like switch.

---
What does your source look like?

What does your load look like?

At what current do you want the limiter to start working?

How stiff do you want the current limiting to be?

--
JF

 

[Jamie]

refigh wrote:

hi,
I need a series current limiter circuit. the characteristic which I
need is that circuit has very low resistance and also limit the
current from going too high,
I want to use it as current protect for a circuit.
I don want to use fuse because it broken in high current. I also dont
want to feed back from any other point of circuit so I can use
something like switch.

When you say high current, to me, that is in the hundreds to
thousands of amps at some voltage far above 100 volts..

Clarification of those specifications will make it possible
to better assist you.


Jamie

 

[John Larkin]

On Mon, 4 Jul 2011 22:02:21 -0700 (PDT), refigh <hamze60@gmail.com>
wrote:

hi,
I need a series current limiter circuit. the characteristic which I
need is that circuit has very low resistance and also limit the
current from going too high,
I want to use it as current protect for a circuit.
I don want to use fuse because it broken in high current. I also dont
want to feed back from any other point of circuit so I can use
something like switch.

There are four or so choices:

1. A real analog, continuous current limiter. It will get hot if the
load shorts.

2. A foldback limiter. Doesn't get as hot.

3. A simulated fuse, like a polyfuse. It opens if the current gets too
high, but you have to kill the power source for a while to reset it.
Polyfuses aren't very precise.

4. A device that senses over-current and opens up, but retries
periodically. Ancient Ford pickup trucks had these, a bimetal-based
self-resetting fuse. It can be done electronically, of course. I'm
designing a circuit right now that needs such a current limiter.


We were having a burger today at In-n-Out and the guys at the next
table were talking about "reclosers", and I had to explain to Mo what
they are. It's a circuit breaker, used in AC power systems, that will
open up on overload but attempt to re-close the circuit automatically,
some number of times, before it gives up.

John

 

[P E Schoen]

"John Larkin" wrote in message
news:0af717h9mmnd28164i5r821ndcfhodef5u@4ax.com...

We were having a burger today at In-n-Out and the guys at the
next table were talking about "reclosers", and I had to explain to
Mo what they are. It's a circuit breaker, used in AC power systems,
that will open up on overload but attempt to re-close the circuit
automatically, some number of times, before it gives up.

Recloser testing is one of my specialties. I have a patent on a recloser
test set:
http://www.freepatentsonline.com/4307345.html

More recently I developed an improved measurement device called an
Ortmaster:
http://www.pstech-inc.com/ortmastr.htm

and now I have a more modern version:
www.ortmaster.com

A typical recloser has two fast and two delayed operations, with about 1 to
2 seconds between tries. The first two are designed to recover after
transient events such as lightning, wind-blown wires touching, and tree
branches. The delayed shots maintain fault current for up to several seconds
in an attempt to burn off the source of the fault, which could be a small
tree branch or an animal such as a dreaded squirrel, which would then become
a "crispy critter" http://www.youtube.com/watch?v=7bmIKrU2jQU

Paul

 

[John Larkin]

On Wed, 6 Jul 2011 01:18:25 -0400, "P E Schoen" <paul@pstech-inc.com>
wrote:

"John Larkin" wrote in message
news:0af717h9mmnd28164i5r821ndcfhodef5u@4ax.com...

We were having a burger today at In-n-Out and the guys at the
next table were talking about "reclosers", and I had to explain to
Mo what they are. It's a circuit breaker, used in AC power systems,
that will open up on overload but attempt to re-close the circuit
automatically, some number of times, before it gives up.

Recloser testing is one of my specialties. I have a patent on a recloser
test set:
http://www.freepatentsonline.com/4307345.html

More recently I developed an improved measurement device called an
Ortmaster:
http://www.pstech-inc.com/ortmastr.htm

and now I have a more modern version:
www.ortmaster.com

A typical recloser has two fast and two delayed operations, with about 1 to
2 seconds between tries. The first two are designed to recover after
transient events such as lightning, wind-blown wires touching, and tree
branches. The delayed shots maintain fault current for up to several seconds
in an attempt to burn off the source of the fault, which could be a small
tree branch or an animal such as a dreaded squirrel, which would then become
a "crispy critter" http://www.youtube.com/watch?v=7bmIKrU2jQU

Paul

Sounds dramatic. In EE school one day they showed us a film of the LA
power department test yard "greatest hits", massive explosions and
arcs and fireballs from transformers and breakers and stuff. Fun.

When I blow up a SOT-23 opamp, it makes a tiny pip! at best.
Electronic design isn't very macho, but it does keep us out of the
rain.

John

 

[P E Schoen]

"John Larkin" wrote in message
news:gu7a17146r7gfl2dlsi2adg08ips8al925@4ax.com...

Sounds dramatic. In EE school one day they showed us a film of the
LA power department test yard "greatest hits", massive explosions
and arcs and fireballs from transformers and breakers and stuff. Fun.

When I blow up a SOT-23 opamp, it makes a tiny pip! at best.
Electronic design isn't very macho, but it does keep us out of
the rain.

I saw a movie by Bussmann (now Cooper) showing the difference between a
standard low voltage (600V) MCCB with about 10kA interrupting rating
compared to a current limiting fuse. Even with the current limited to 10kA,
the circuit breaker was damaged and had to be repaired before it could be
used again, but at the full 200kA it blew up quite dramatically. The LPS
fuse just shook a little bit and let out a small puff of magic smoke.
Youtube has some good videos of high voltage arcs and accidents:

http://youtu.be/BIiiMa1IGvM
http://youtu.be/vqgNrj6oEdc
http://youtu.be/vCpH19TkMqo
http://youtu.be/BtQtRGI0F2Q
http://youtu.be/-iClXrd50Z8
http://youtu.be/2LZ0q78OWZE
http://youtu.be/DCyMS7FKCZc
http://youtu.be/uMV1jmDn3o4 (60A thru 20A breaker - actually a 3x overload
may be 60-90 seconds trip)

Tour of a recloser shop which uses a Phenix Technologies test set.
http://youtu.be/9BUGi8BXZGA

I worked for them 1990-1992 at their shop in Accident, MD. Previously I had
worked at EIL which was in Sparks, MD. Good names for towns where electrical
testing is done!

This an interesting test of a fast-operating recloser vs one with longer
closed intervals:
http://youtu.be/rdcAS5i_OSk

A nice overview of an Aussie switchgear mfr:
http://youtu.be/8fau2pTjLTc

Here is a video by one of my customers:
http://youtu.be/xN7_0t7QskI

I repaired (actually replaced) his 13 year old Ortmaster when it had been
run over by a truck in an accident. The D-sub connector had broken but the
unit still worked when I bent it back into shape. The enclosure is 14 gauge
steel. Now that's rugged!
http://www.pauleschoen.com/pix/ORTM-1_Damaged_01.jpg
http://www.pauleschoen.com/pix/ORTM-1_Damaged_02.jpg

Thanks,

Paul
www.ortmaster.com