Revisions to Designing a current limiting circuit for my project

Tweeted twitter.com/StackElectronix/status/1199206206289698816

occurred Nov 26, 2019 at 6:00

broken image fixed (click 'rendered output' or 'side-by-side' to see the difference; image retrieved via Wayback Machine); for more info, see https://gist.github.com/Glorfindel83/9d954d34385d2ac2597bbe864466259f

Source Link

edit approved Nov 25, 2019 at 9:46

Glorfindel

1.2k
3
15
20

I've got a small DC brushless motor for which I would like to set a current limiting circuit as a protection against over-current.

I thought I could pull it off with a simple fuse (or those current limiting fuse-like chips) but I can't. The fuse would only work to protect against short circuits because I want to set my limit just 20% (max!) above the nominal current draw of the motor.

I didn't design the motor electronics, and my competence in electronics is not great but I was basically wondering if I could use a circuit similar to those:

Schematic
_{(source: wikimedia.org)}

and if so how I would select the correct components (like transistors and resistors)?

The nominal current draw for the motor is 1.5A. I'd like the circuit to cut the power off when the current is 1.8A or more.

The reason I need something like this is because the load on the motor can vary greatly and would sometimes bring the current draw to 1.8A and more (which I consider unsafe - it's very subjective but that's what I'd like to do...)

Any idea?

edit: clarification: I want to switch power off when the current exceeds a certain value, which has to be about 20% max higher than the nominal power draw of my motor.

edit: how about that second schematic?

I've got a small DC brushless motor for which I would like to set a current limiting circuit as a protection against over-current.

I thought I could pull it off with a simple fuse (or those current limiting fuse-like chips) but I can't. The fuse would only work to protect against short circuits because I want to set my limit just 20% (max!) above the nominal current draw of the motor.

I didn't design the motor electronics, and my competence in electronics is not great but I was basically wondering if I could use a circuit similar to those:

Schematic

and if so how I would select the correct components (like transistors and resistors)?

The nominal current draw for the motor is 1.5A. I'd like the circuit to cut the power off when the current is 1.8A or more.

The reason I need something like this is because the load on the motor can vary greatly and would sometimes bring the current draw to 1.8A and more (which I consider unsafe - it's very subjective but that's what I'd like to do...)

Any idea?

edit: clarification: I want to switch power off when the current exceeds a certain value, which has to be about 20% max higher than the nominal power draw of my motor.

edit: how about that second schematic?

I've got a small DC brushless motor for which I would like to set a current limiting circuit as a protection against over-current.

I thought I could pull it off with a simple fuse (or those current limiting fuse-like chips) but I can't. The fuse would only work to protect against short circuits because I want to set my limit just 20% (max!) above the nominal current draw of the motor.

I didn't design the motor electronics, and my competence in electronics is not great but I was basically wondering if I could use a circuit similar to those:

Schematic
_{(source: wikimedia.org)}

and if so how I would select the correct components (like transistors and resistors)?

The nominal current draw for the motor is 1.5A. I'd like the circuit to cut the power off when the current is 1.8A or more.

The reason I need something like this is because the load on the motor can vary greatly and would sometimes bring the current draw to 1.8A and more (which I consider unsafe - it's very subjective but that's what I'd like to do...)

Any idea?

edit: clarification: I want to switch power off when the current exceeds a certain value, which has to be about 20% max higher than the nominal power draw of my motor.

edit: how about that second schematic?

replaced http://upload.wikimedia.org/ with https://upload.wikimedia.org/

Source Link

edited Mar 9, 2017 at 18:04

Community Bot

1

I've got a small DC brushless motor for which I would like to set a current limiting circuit as a protection against over-current.

I thought I could pull it off with a simple fuse (or those current limiting fuse-like chips) but I can't. The fuse would only work to protect against short circuits because I want to set my limit just 20% (max!) above the nominal current draw of the motor.

I didn't design the motor electronics, and my competence in electronics is not great but I was basically wondering if I could use a circuit similar to those:

Schematic http://upload.wikimedia.org/wikipedia/en/8/81/Current_limiting_using_bjt.gif

and if so how I would select the correct components (like transistors and resistors)?

The nominal current draw for the motor is 1.5A. I'd like the circuit to cut the power off when the current is 1.8A or more.

The reason I need something like this is because the load on the motor can vary greatly and would sometimes bring the current draw to 1.8A and more (which I consider unsafe - it's very subjective but that's what I'd like to do...)

Any idea?

edit: clarification: I want to switch power off when the current exceeds a certain value, which has to be about 20% max higher than the nominal power draw of my motor.

edit: how about that second schematic?

I've got a small DC brushless motor for which I would like to set a current limiting circuit as a protection against over-current.

I thought I could pull it off with a simple fuse (or those current limiting fuse-like chips) but I can't. The fuse would only work to protect against short circuits because I want to set my limit just 20% (max!) above the nominal current draw of the motor.

I didn't design the motor electronics, and my competence in electronics is not great but I was basically wondering if I could use a circuit similar to those:

Schematic http://upload.wikimedia.org/wikipedia/en/8/81/Current_limiting_using_bjt.gif

and if so how I would select the correct components (like transistors and resistors)?

The nominal current draw for the motor is 1.5A. I'd like the circuit to cut the power off when the current is 1.8A or more.

The reason I need something like this is because the load on the motor can vary greatly and would sometimes bring the current draw to 1.8A and more (which I consider unsafe - it's very subjective but that's what I'd like to do...)

Any idea?

edit: clarification: I want to switch power off when the current exceeds a certain value, which has to be about 20% max higher than the nominal power draw of my motor.

edit: how about that second schematic?

I've got a small DC brushless motor for which I would like to set a current limiting circuit as a protection against over-current.

I thought I could pull it off with a simple fuse (or those current limiting fuse-like chips) but I can't. The fuse would only work to protect against short circuits because I want to set my limit just 20% (max!) above the nominal current draw of the motor.

I didn't design the motor electronics, and my competence in electronics is not great but I was basically wondering if I could use a circuit similar to those:

Schematic

and if so how I would select the correct components (like transistors and resistors)?

The nominal current draw for the motor is 1.5A. I'd like the circuit to cut the power off when the current is 1.8A or more.

The reason I need something like this is because the load on the motor can vary greatly and would sometimes bring the current draw to 1.8A and more (which I consider unsafe - it's very subjective but that's what I'd like to do...)

Any idea?

edit: clarification: I want to switch power off when the current exceeds a certain value, which has to be about 20% max higher than the nominal power draw of my motor.

edit: how about that second schematic?

added 141 characters in body

Source Link

edited Jul 29, 2014 at 22:30

user3617652

31
1
3

I've got a small DC brushless motor for which I would like to set a current limiting circuit as a protection against over-current.

I thought I could pull it off with a simple fuse (or those current limiting fuse-like chips) but I can't. The fuse would only work to protect against short circuits because I want to set my limit just 20% (max!) above the nominal current draw of the motor.

I didn't design the motor electronics, and my competence in electronics is not great but I was basically wondering if I could use a circuit similar to this onethose:

Schematic http://upload.wikimedia.org/wikipedia/en/8/81/Current_limiting_using_bjt.gif

and if so how I would select the correct components (like transistors and resistors)?

The nominal current draw for the motor is 1.5A. I'd like the circuit to cut the power off when the current is 1.8A or more.

The reason I need something like this is because the load on the motor can vary greatly and would sometimes bring the current draw to 1.8A and more (which I consider unsafe - it's very subjective but that's what I'd like to do...)

Any idea?

edit: clarification: I want to switch power off when the current exceeds a certain value, which has to be about 20% max higher than the nominal power draw of my motor.

edit: how about that second schematic?

I've got a small DC brushless motor for which I would like to set a current limiting circuit as a protection against over-current.

I thought I could pull it off with a simple fuse (or those current limiting fuse-like chips) but I can't. The fuse would only work to protect against short circuits because I want to set my limit just 20% (max!) above the nominal current draw of the motor.

I didn't design the motor electronics, and my competence in electronics is not great but I was basically wondering if I could use a circuit similar to this one:

Schematic

and if so how I would select the correct components (like transistors and resistors)?

The nominal current draw for the motor is 1.5A. I'd like the circuit to cut the power off when the current is 1.8A or more.

The reason I need something like this is because the load on the motor can vary greatly and would sometimes bring the current draw to 1.8A and more (which I consider unsafe - it's very subjective but that's what I'd like to do...)

Any idea?

edit: clarification: I want to switch power off when the current exceeds a certain value, which has to be about 20% max higher than the nominal power draw of my motor.

I've got a small DC brushless motor for which I would like to set a current limiting circuit as a protection against over-current.

I thought I could pull it off with a simple fuse (or those current limiting fuse-like chips) but I can't. The fuse would only work to protect against short circuits because I want to set my limit just 20% (max!) above the nominal current draw of the motor.

I didn't design the motor electronics, and my competence in electronics is not great but I was basically wondering if I could use a circuit similar to those:

Schematic http://upload.wikimedia.org/wikipedia/en/8/81/Current_limiting_using_bjt.gif

and if so how I would select the correct components (like transistors and resistors)?

The nominal current draw for the motor is 1.5A. I'd like the circuit to cut the power off when the current is 1.8A or more.

The reason I need something like this is because the load on the motor can vary greatly and would sometimes bring the current draw to 1.8A and more (which I consider unsafe - it's very subjective but that's what I'd like to do...)

Any idea?

edit: clarification: I want to switch power off when the current exceeds a certain value, which has to be about 20% max higher than the nominal power draw of my motor.

edit: how about that second schematic?