The motor is a dvd brushless motor or brushless motor I'm using it in a device that I built to dry wet PCB so I want it in a such way that if I place the PCB on the metal surface the motor should be able to move forward and reverse until I stop. What I want now is a circuit that can auto reverse and forward the motorWhat kind of mechanism is it for?
One device that does this without reversing the motor, is an automotive wiper motor and mechanism.
There are other similar mechanical ways.
This also will really be helpfulOne simple demo.
Yes, I have used relays to work it out manually and it's ok. Does it mean reversing motor constantly will affect the life of the motor?Have you explored all the options for doing it mechanically and maintain one motor direction?
It sounds like an application that could be open to it?
It can often be troublesome, when you reverse a motor constantly with no pause in between.
If it is a brushless motor, I assume it has a PWM drive if some kind?
Heating can occur.Yes, I have used relays to work it out manually and it's ok. Does it mean reversing motor constantly will affect the life of the motor?
When I swap the polarity it move forward and reverse. Yes, it is tray in and out and also the laser moves.I have never seen a brushless motor in a consumer grade DVD or CD player. And if the motor reverses with just swapping the polarity of the motor I doubt that it is brushless. Have you tried running the motor in both directions just by reversing the power connections?? What voltage does the motor run on?? If it is a BLDC motor the driver may have a reverse control line. What function in the DVD player did the motor have? Load/unload, tray IN/Out? disc rotate? or laser move ? three different functions, three different motors.
Do you have any schematic to support it.OK, then it is simple to reverse and the relay scheme described will work very well.
So far this what I designed and its working fine. The motor auto forward and reverse depending on the RC network to operate forwarding and reversing . Please can you go through if there is no mistake in my circuit.The circuit in post #15 will work very well, BUT it may be that the relay voltage and the motor voltages are not the same. In that case the motor voltage should only be connected to the relay contacts feeding the motor, and the relay coil supply can be connected as the supply connection shown on the drawing.
To stop the motor motion the motor supply must be switched off.
This control scheme does not include a stop mode.
From your drawing both relays are activated when the output from the 555 is high.
The drawing below shows the corrections circled in red.
View attachment 272281
Hi sghioto, The way the motor is connected to the relay contact requires both relays to be energised for one direction of the motor and both relays to be de-energised for the other direction. So his circuit is correct for driving the motor backwards and forwards. But the circuit has no means of controlling the positions when the motor reverses.
A third version of the design in post #15 could be made using three single pole double throw relays. That design controls the points where the direction changed by the position of the limit switches.
The circuit in post #17 could be modified by replacing the 555 and the timing components with another relay wired in the same way as the left hand set of changeover contacts in post #15.
Les.
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