Motor Control with Start/Emergency Stop and limit switch

Thread Starter

Hekfc-88

Joined Dec 5, 2018
8
Hello, I am trying to motorize a can seamer. The seamer has two arms used to complete the operation. Arm one moves in and performs part of the process and then moves back out and arm two moves in and completes the process and moves out. Once arm two has moved out I want it to trip a limit switch to stop the motor so that I can remove the completed can and start the process over again. I should note that the limit switch will not change state again till arm two begins to move again after Arm one is finished.

The motor is a 120 VAC and is currently operated with a foot switch. I plan to remove the foot switch and instead utilize push button switches. The difficulty I am having is how to wire up a start/emergency stop and the limit switch so that the motor shuts off at the end of the process but is in position to start back up when the start button is pushed. I do not need to motor to reverse as the can seamer action is all done in one direction.

I am sure there is a simple way to implement this but it eludes me at the moment and I apologize if this is the wrong forum section for this type of question.

Thank you
 

Thread Starter

Hekfc-88

Joined Dec 5, 2018
8
So the present footswitch is held down through the process or a momentary action at present?
Max.
Held down from start to finish. That is one of the issues if it is not let go and the process starts over again on an already seamed can it can ruin the seamer heads.
 

Thread Starter

Hekfc-88

Joined Dec 5, 2018
8
One other item I forgot to put in the OP is that it takes 22 revolutions of the shaft to complete the process. So, I guess a sensor that counts the shaft revolutions would be an option but that is not my first choice.
 

MaxHeadRoom

Joined Jul 18, 2013
19,199
I assume you would like a simple L.S./Relay solution if possible, are you into any electronic solution.
I would also guess that the arm motion is geared exactly to 22 revolutions for start to finish?
Max.
 

Thread Starter

Hekfc-88

Joined Dec 5, 2018
8
I assume you would like a simple L.S./Relay solution if possible, are you into any electronic solution.
I would also guess that the arm motion is geared exactly to 22 revolutions for start to finish?
Max.
Yes, a simple relay option is where I first expected this to go but I am open to other options depending on complexity and what other things I would need to acquire.

As for the revolutions. At the end of the 22nd revolution arm 2 is back at its end of cycle and arm 1 will start to move in as revolution 23 begins.
 

GetDeviceInfo

Joined Jun 7, 2009
1,645
Something in the works makes a cycle, then continuously repeats. Mount a switch to detect that cycle. The switch turns off your motor via appropriately rated relay. Parallel that switch with a momentary push button to run off the switch, allowing the cycle to repeat.
 

KMoffett

Joined Dec 19, 2007
2,772
With two MOM NC limit switches and a latching (DPDT feedback) relay circuit, you need a delay between the moment A arm retracts and B arm starts to move in to keep the motor running.

Ken
 
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KMoffett

Joined Dec 19, 2007
2,772
I think I have a solution, but need someone else to look at it.

Pushing START switch powers the motor and and RLY1, closing its contacts. START is held until the first arm moves enough to close the ARM1 limit switch. This latches RLY1 on, and closes the contacts on RLY2 and starts its timer. RLY2 maintains power to RLY1 and the motor after the first arm retracts and ARM1 opens, and until the second arm moves and closes ARM2. When the second arm retracts and opens ARM2, RLY1 is unlatched and the motor stops. At least that's the concept.

This is the Delay-on-Break relay that I was think of:
http://www.airotronics.com/AOTpdfs/delayonbreak/Airotronics-TGML.pdf

Ken

Motor AC Start-Cycle1-Cycle2-Stop.jpg
 
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