Instructables

I want to use a very simple circuit to start, stop and reverse the motor. Does anyone have any idea of such a circuit ?

We are currently doing a project to retract a certain beam and to extend it. We require a switch to start the motor to extend the beam, stop it and retract the beam when needed. The stopping part would be automatic. The start can be activated from a switch and the reverse switch would be connected to our previous circuit. We really need help for this motor circuit.

seandogue5 years ago
What are your fundamental operating parameters? Specifically Motor HP and Voltage? I'm not gonna touch this until I know. A "Beam", could be a rather large object, and electrical safety codes require specific treatment of motor circuits. Is this by any chance an industrial application?
rukesh (author)  seandogue4 years ago
This is a prototype project, so the beams would of light material like aluminium and around 2 feet only. No, this is not an industrial application, a project for year-end students. A normal geared-down motor around 12V
thanks for the reply. Sorry to be a prig about the issue...I assume Re-design's and frollards advise was sufficent?
rukesh (author)  seandogue4 years ago
It is quite sufficient, am thinking if I need another circuit with a timer or L6203 Full Bridge Driver to control the direction and speed of the motor and also we need to know how to connect the water sensor circuit to the motor to automatically reverse it
Re-design4 years ago
Get the system working with out the limit switches then add the limits switches in one at a time so that if something does not work you know what you did that broke it.
frollard5 years ago
The most rudementary design involves a latching (non-momentary) switch, with end stop switches to stop the motor at the 'start and end'. Attached is how a double pole double throw switch can be hooked up to a motor to provide forward, off, and reverse wiring to a dc motor. Adding the end-stops would just be on the output lines for forward and reverse to only stop them in the direction indicated by the switch. Say output A extends the motor. You would put the end stop switch on A, and the 'minimum' stop switch on B.
dpdt.PNG
**chheck that, 'C' not 'B' above for the minimum stops.
Yep. That would do it.
Re-design5 years ago
It's not going to be simple to you, if you haven't figured it out on your own already. But it's not going to be that complicated either. You need a SPDT switch to move the motor to the extended position then a limit switch to automatically stop it. Reverse the position of the SPDT switch to retract it. Put the extend limit switch in the extend leg of the circuit and the retract limit switch in the return leg of the switch. You said the stopping is the automatic portion of the operation. Use a normally closed reed, pushbutton or lever switch for the limit switch. It's only there to break the circuit when the limit is reached.
rukesh (author)  Re-design4 years ago
The reverse and stop is automatic. Like for example, the beam would be extended from a switch and it must stop after a while automatically. The reverse function would start to operate when it rains cause it should be connected to the water sensor circuit and the motor should stop after it reverses.
And now that I think about it after waking up fully it will take a DPDT switch that will reverse the polarity to the motor.
And maybe ... a couple of diodes that I thought about on the way to the office this morning. I'lll try to post a diagram later today. Maybe I didn't have it figured out as well as I thought I did early this morning. I'll let you know later if I think of anything else you need.
rukesh (author) 4 years ago
Thank you people for your answers. I am currently trying out the circuit with your ideas. A diagram would help a lot cause am quite new to this, thanks !
Re-design has it, but it may need to be done with relays depending on your motor type and current rating