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VFD E Stop wiring

You could add a contactor as the power feed to the VFD. I wired my lathe so the ON switch turns on the factory contactor which then feeds power to the VFD. Hitting the OFF switch kills the contactor and kills power to the VFD killing power to the motor.
My VFD is set to restart on a power outage so when it gets AC back it continues from the previous settings.
Maybe not technically an E-stop but it works for me.

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thanks, I did put push buttons and a contactor into the box but they are before the VFD. There is a large e stop button the side the case that I was think to use wired to the VFD. It should be either wired or removed.... which leaves a hole in the case. I guess I could wire it in series with stop button I suppose, but I would rather have it low voltage

There are so many of these out there, there has to be a simple way
 
Don't know what the VFD does with its e stop function, there's no external braking resistor and we all know what the documentation is like.

I'd be fine with NO estop because I'm the only one using it (rules are an E stop as to be NC so a broken wire doesn't disable the e stop) but I'm working with the existing NC estop. I think you have the use the collect sink but I just put it in series with the off switch and it works well enough. :).

Thanks for the help gents
 
With the at drives they are made to run a fan, so very limited function. Think a simple 3 position maintained switch. Fwd off rev. They have a keyed function as well but I found it to not be what I wanted.

What I did with my drive system is I used two relays, they are small 1pole so I needed two. one relay is wired with the good old 3 wire start no push button, stop nc push button system using its contacts as the holding contacts. The second relay is switching the common from the drive through my selector fwd rev switch, to run the drive in fwd or rev. The C phase part of my selector switch is inline with start stop circuit and shuts down as needed. God that sounds way more complicated than it is.
 
A true E-stop is one thing… a functional “e-stop” is another.

I do not recommend cutting the power to the drive as a functional estop for a lathe/mill application… why?

That will cause the drive to “freewheel” to a stop likely and not “ramp” or “brake” to a stop.

On a full featured drive there usually is a parameter to use an input as a accel/decel time switch, and a spot to program in a second set of accel/decel time settings…..

What I have done is when the estop is depressed, and the estop relay kicks out, an NC contact closes and the decel time goes to “fast” like 0.5sec, and a braking resistor allows that to happen.

The other contact of the relay I would run the common of the other inputs through on an NO contact like @djberta mentions.

As far as a “functional” estop is concerned, that’s about as good as you can get for a home shop lathe or mill.

A real estop according to IEC or whatever has a whole bunch of requirements that meh, don’t really matter for us.

My 2c.
 
Gosh that's a tough question. E-Stop stands for Emergency Stop. Back when I was working on machines with 30T presses the ESTOP mean "NOW". I don't remember for sure but I think power was not taken from the PC but otherwise all AC power was disconnected.

I think the reason was that if the compartment lid safety switches were over-ridden for service and a service tech hand was 'held' in the press mechanism there had to be a way to remove the remnants of his hand so he could go to the hospital.

Switching off all AC power and signalling ESTOP to the software stops all motion, both from a software perspective and mechanically. However, braking a free running motor does bring up an interesting question. How to handle that?

On my original milling machine DC Servo system I designed a system to handle decelerating motors by switching in a load resistor across the power supply to bring down the voltage above a certain set point. Decelerating motors are generators and this resistor effectively shorted them out.

In parallel with the FET doing this as also a relay with NC contacts. The ESTOP circuit enabled this relay so the contacts were in the NO position and the resistor was only on the load with an over voltage condition. However, hit the ESTOP and the relay released and the contacts completed the circuit to short out the power supply. That 105VDC motor power supply was gone in under 1 second.

So a really safe system ESTOP _should_ disconnect power to the motor and if the motor can freewheel then the windings should be shorted out or at least loaded with a braking resistor.

If that all makes sense. The attached drawing shows the idea. The LED flickers as the motor decelerates and the voltage exceeds the set point. However if the ESTOP removes the 12V the relay releases and the shunt is put across the power supply.
 

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