Simple DC motor control? Fuse?

bulaboo

Joined Aug 20, 2022
10
Hello everybody!

Any idea how to make a simple, robust, device (fuse?) that releases a relay when a 6 Volt DC motor is jammed, and the current exceeds ~40 mA?
Some kind of a shunt resistor and measuring the voltage?

All ideas, hints and advice are very welcome.

bulaboo

Joined Aug 20, 2022
10
Let's assume that the motor is already running when this take place… Ignore the start current peak.

(Vout goes to the relay thru which V+ comes.)

LowQCab

Joined Nov 6, 2012
2,506
If You need sophisticated Control try this ............
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bulaboo

Joined Aug 20, 2022
10
If You need sophisticated Control try this ............
Thank you. That's a great one but I try the opposite, as simple as possible.
Maybe it isn't possible electronically, maybe the solution is a spring and a micro switch?

Danko

Joined Nov 22, 2017
1,444
...I try the opposite, as simple as possible.
Try this, simplest one:

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bulaboo

Joined Aug 20, 2022
10

Danko

Joined Nov 22, 2017
1,444
IMPORTANT >> Where do I connect V? Is it between R2 and C1?
As shown on diagram +V connected to node "A".
That's it. No more any voltages.
Motor connected between "A" and "B".
Motor shown as resistor.
Circuit for 6 V:

Last edited:

bulaboo

Joined Aug 20, 2022
10
As shown on diagram +V connected to node "A".
That's it. No more any voltages.
Motor connected between "A" and "B".
Motor shown as resistor.
Thank you for the clarification. I somehow looked totally wrong. Now it makes sense, thanks!

Danko

Joined Nov 22, 2017
1,444

bulaboo

Joined Aug 20, 2022
10
Yes, resistance value of R3 is 3Ω.
Thank you!

Good News (for me): thanks to you guys I re-started my ”electronics hobby” It was on kind of a pause since 1980's or something. Now I try to learn use EasyEDA. Great stuff!

k1ng 1337

Joined Sep 11, 2020
687
Thank you!

Good News (for me): thanks to you guys I re-started my ”electronics hobby” It was on kind of a pause since 1980's or something. Now I try to learn use EasyEDA. Great stuff!
Get yourself an Arduino Uno. If you are only looking for minor precision to see if there is a large change in current, the ATmega328 microcontroller can handle that and plenty more. The onboard ADC can read a shunt resistor with little programming. Good luck on your quest and welcome to the forum.