Hi,
I am wondering if somebody could help with a current limiting circuit I am trying to implement.
What I have is a small 12v dc motor with gearbox.
This will be operating a mechanical valve.
As the valve reaches the end of its travel the motor will load and begin to stall.
This valve will be operated at most once a day.
The motor/gearbox does not have enough torque to cause damage to the valve, just enough to close it tightly. Also the gearbox is a worm type and will hold the valve closed without the need for constant power.
Due to is envoirnment limit switches cannot be used.
The unloaded/normal operating current is 50mA.
What I am looking for is a way to shut this motor off when is reached max travel/ beginning to stall.
For example when the motor current rises to 100mA current limiting will act and reduce the current to near 0mA or have a relay act and break the circuit.
The circuit can remain in an open or current limited state until it is manually reset i.e. to open the valve.
I do not have experience with building current limiting circuits.
What I have been looking at online are circuits using LM317 and LM339 (as I have both in storage) as current limitings circuits, but not sure if im on the correct path for the above application.
Thanks in advance,
Nigel
I am wondering if somebody could help with a current limiting circuit I am trying to implement.
What I have is a small 12v dc motor with gearbox.
This will be operating a mechanical valve.
As the valve reaches the end of its travel the motor will load and begin to stall.
This valve will be operated at most once a day.
The motor/gearbox does not have enough torque to cause damage to the valve, just enough to close it tightly. Also the gearbox is a worm type and will hold the valve closed without the need for constant power.
Due to is envoirnment limit switches cannot be used.
The unloaded/normal operating current is 50mA.
What I am looking for is a way to shut this motor off when is reached max travel/ beginning to stall.
For example when the motor current rises to 100mA current limiting will act and reduce the current to near 0mA or have a relay act and break the circuit.
The circuit can remain in an open or current limited state until it is manually reset i.e. to open the valve.
I do not have experience with building current limiting circuits.
What I have been looking at online are circuits using LM317 and LM339 (as I have both in storage) as current limitings circuits, but not sure if im on the correct path for the above application.
Thanks in advance,
Nigel