Circuit two would work, But if you're asking this, you shouldn't mess with mains power.
Maybe safer to power the Arduino from a cellphone charger (connected to the USB socket),
and have a while() loop in setup() that waits for a start button press.
Leo..
No, that's not correct. That way the contactor will always turn on. But connect 1 and 3 to the PSU and 2 and 4 to the supply and it looks more like it.
But that way there is still no way to turn it on. If the buttons are single pole (which i guess) above design will also not help.
So for all (complete new wiring):
2 and 4 to supply
1 and 3 to PSU
A2 to 2
A1 to 3
NO button between 3 and 4 (on button)
NC button in the A1 OR A2 connection of the coil (off button)
Wawa:
Circuit two would work, But if you're asking this, you shouldn't mess with mains power.
Maybe safer to power the Arduino from a cellphone charger (connected to the USB socket),
and have a while() loop in setup() that waits for a start button press.
Leo..
Thanks Leo
My arduino project also has a 12V motor with a small cutting disk that is connected directly to the PSU ( not controlled by the Arduino for various reasons ) so having that section of the project isolated from the mains after a mains power failuse is the reason for the Contactor. I can not control the power to that motor with the Arduino.
So for all (complete new wiring):
2 and 4 to supply
1 and 3 to PSU
A2 to 2
A1 to 3
NO button between 3 and 4 (on button)
NC button in the A1 OR A2 connection of the coil (off button)
Thanks septillion
so like this image ?
.. and a dumb question .. any specific reason to have the mains in to pins 2 & 4 instead of 1 & 3 ? Is it a characteristic of the contacts that dictate which direction to use the device ?
Yeah, like the image. But your second image is fine as well. The relay has no direction. It was just me who found it more logical to express it with bottom as input
septillion:
Yeah, like the image. But your second image is fine as well. The relay has no direction. It was just me who found it more logical to express it with bottom as input
It's ambiguous. Are the N/C button and N/O button connected to terminal 3? Most electrical diagrams use a dot at an intersection of wires like that to show that they are connected. If there's no dot, the convention is that it represents unconnected wires.
This is a standard circuit in relay logic called a seal in circuit. Try matching this diagram against your drawing:
The relay coil that is the output for this branch is shown on the right, and the switches and relay contacts controlling that coil are shown on the left.
The stop button is in series with the entire branch so that it can interrupt current when pressed. It must be N/C, so that current flows through it by default.
An N/O button and one N/O relay contact are in parallel. It's not shown well in this diagram, but it's necessary for the contact to be from the same relay as the output coil for this branch.
When this circuit first has power applied to it, both the contact and button are open, so the relay coil is de-energized. When the button is pushed, a path is made for current to energize the coil. This also closes the contact that is in parallel with the button, so that when the button is released the relay remains on. The relay is holding itself on with its own contact.
Since the stop button is in series with everything, pressing it stops all current in the branch, de-energizing the coild and releasing the contact that's bypassing the button, so that when you release the stop button current remains blocked until you press start again.
