If I were to have a motor, and stopped it with my fingers, what component would shut the motor off if it experiences a certain amount of load? This is on a normal DC motor, but i could also use a stepper motor. Thanks! Feel free to ask for more information.
Hi Mathew,
I see that Doug has covered things very well while I was drawing up this circuit. I will post anyway just in case it is of any help to you.
Here is a little circuit that illustrates how this can be accomplished. The potentiometer R-1 determines the level of the current necessary to trip the relay. As long as the voltage at pin 4 of the comparator is higher than the voltage at pin three the comparator is low and the connection to the motor is made by the relay RL-1. As you increase the load to the motor the current in the resistor R-2 increases and this also increases the voltage at pin 3 of the comparator. When the voltage at pin 3 becomes higher than pin 4 of the comparator the comparator will turn on the MOSFET Q-1. When the MOSFET Q-1 turns on it will energize the relay which will pull in and turn off the motor. The second thing that RL-1 does when it energizes is to turn itself on. We say that the relay latches. The relay will remain energized and the motor will remain unconnected until the power is turned off or the reset switch SW-1 is pushed. I have not put in resistor or component values as they would depend on things I do not know about your motor or your needs. There may be simpler ways to do this but this is the first circuit that I came up with.
John
If you click on the schematic it will get a little bit bigger.
John
Hi Mathew,
I see that Doug has covered things very well while I was drawing up this circuit. I will post anyway just in case it is of any help to you.
Here is a little circuit that illustrates how this can be accomplished. The potentiometer R-1 determines the level of the current necessary to trip the relay. As long as the voltage at pin 4 of the comparator is higher than the voltage at pin three the comparator is low and the connection to the motor is made by the relay RL-1. As you increase the load to the motor the current in the resistor R-2 increases and this also increases the voltage at pin 3 of the comparator. When the voltage at pin 3 becomes higher than pin 4 of the comparator the comparator will turn on the MOSFET Q-1. When the MOSFET Q-1 turns on it will energize the relay which will pull in and turn off the motor. The second thing that RL-1 does when it energizes is to turn itself on. We say that the relay latches. The relay will remain energized and the motor will remain unconnected until the power is turned off or the reset switch SW-1 is pushed. I have not put in resistor or component values as they would depend on things I do not know about your motor or your needs. There may be simpler ways to do this but this is the first circuit that I came up with.
John
If you click on the schematic it will get a little bit bigger.
John
