Reverse the rotation of motor.!

Go To Last Post
11 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I was building this circuit where in there is a gate,which closes when a heavy vehicle approaches it. So, initially when the gate is open the motor has to rotate in clockwise rotation. On reaching horizontal position,after checking the weight of the vehicle, the motor should rotate in the anticlockwise direction to open. Any ideas? I have to do this without a microcontroller.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

JC

Attachment(s): 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Well, the first question is are you actually switching the power leads to the motor, or is there a motor controller, and you are switching a control signal?

One could probably wire up some relays to act like a Flip-Flop and reverse the output power, the final relay being a DPDT relay with the terminal connections criss-crossed.

But why?

If the system gets out of synch then someone has to manually re-set it.

Additionally, powered gates usually have limit switches for the gate, and emergency open, and emergency stop conditions, etc. All of these can be most easily implimented with a micro driving the motor's controller, or worst case, for infrequent use, a relay to drive the motor.

JC

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

How you change the motor rotation depends on the kind of motor.

If it is a DC motor, as on my entrance gate, you change the polarity of the motor power. If it is an AC motor, you have to change how the power is applied to several terminals on the motor.

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:
Well, the first question is are you actually switching the power leads to the motor, or is there a motor controller, and you are switching a control signal?

Yes , i will be using a motor driver ic L293D.But the swtiching has to be automatic , nothing manual.Any idea on how to reverse the power?

Quote:
How you change the motor rotation depends on the kind of motor.

If it is a DC motor, as on my entrance gate, you change the polarity of the motor power. If it is an AC motor, you have to change how the power is applied to several terminals on the motor.


Im using a DC motor, the polarity has to be reversed after it reaches the horizontal position.I can give a trigger signal there, but after the trigger will it be permanantly reversed till the gate reaches vertical position?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

jayakrishnan wrote:
Im using a DC motor, the polarity has to be reversed after it reaches the horizontal position.I can give a trigger signal there, but after the trigger will it be permanantly reversed till the gate reaches vertical position?
You need to sketch out the actual sequence of "events". Somewhere in that set will be "gate reached target position (horizontal or vertical). Remove power. Wait for next signal. Reverse polarity. Wait for end limit switch. Remove power."

Ross McKenzie ValuSoft Melbourne Australia

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:
I have to do this without a microcontroller.

When are designing a system for heavy vehicles and you are able
to use L293D, I cannot imagine any reason, why you can't or won't, consider an MCU, unless this is a school project in motor control & relay logic. But why exclude the use of MCU.

Quote:
after checking the weight of the vehicle,

I presume that will be done without an MCU too will it!

You could implement the whole design with compressed air or hydraulics. pressure sensors and a a few control valves with some simple wired logic.

Charles Darwin, Lord Kelvin & Murphy are always lurking about!
Lee -.-
Riddle me this...How did the serpent move around before the fall?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

LDEVRIES wrote:
Quote:
I have to do this without a microcontroller.

You could implement the whole design with compressed air or hydraulics. pressure sensors and a a few control valves with some simple wired logic.

Or an aged attendant wearing an official looking hat. Where is the employment office?

Ross McKenzie ValuSoft Melbourne Australia

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:
You could implement the whole design with compressed air or hydraulics. pressure sensors and a a few control valves with some simple wired logic.

Why not go completely mechanical with some sort of balancing counterweight system, and a load plate. When a vehicle drives onto the load plate, if it's of sufficient weight to overcome the counterweight, the load plate drops a bit, and a mechanical linkage transfers that movement to close the gate.

- S

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hello,

Why a DC motor?

Thanks

Just some guy

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:
Why a DC motor?

Exactly! Reversing most AC motors is easily using a DPDT relay, by reversing the split phase start winding.

However, the big question(which has been asked before), why not use a MCU for the smarts??

Charles Darwin, Lord Kelvin & Murphy are always lurking about!
Lee -.-
Riddle me this...How did the serpent move around before the fall?