Wiring extra NVR switch in series

[E-wan]

I'm contemplating adding a foot operated nvr switch to my drill press

Is it appropriate to wire this in series like so

Plug---foot NVR switch--- machine mounted switch----motor

Or would I be adding additional resistance to have two switches before the motor?

Thanks

Ewan


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[sunnybob]

Is the machine switch NVR as well? That would make the wiring slightly more complicated.

The simpleast way would be to run the live feed in down to the ordinary footswitch. Using the blue wire on the same cable run the power back to the machine NVR switch. There fore as soon as the foot switch is operated, the NVR on the machine will drop out.
Exactly the same way as a light switch works.
Its perfectly safe to use the blue wire as power, but you must mark each end if it with red tape or sleeve, to let anyone in the future know its being used as a live.
If the footswitch is an ON/OFF type, then it would need to be reset before the NVR would work.
If its a spring loaded "panic button" then the NVR on the machine would restart the machine when required.

 

[E-wan]

Thanks

I think machines switch isn't nvr so I presume I will be adding an extra foot switch and it would be the only nvr switch

At least I don't think the machine switch is NVR not the panic button type anyway.

Is it easy to tell from the wiring if I open the switch up if it is an nvr switch or not.

Thanks

Ewan

Photographs of current machines switch attached

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[sunnybob]

Thats an NVR switch.
Sometimes there is a big red flip over cover, which then turns it into a panic button. Then the red flap has to be lifted to start the machine again.

 

[Sideways]

It looks like an NVR but the easiest way to tell if the existing switch IS an NVR is to see if it works like one.
Plug the machine in, press start and machine will run.
Unplug it without pressing the stop button first and the machine will stop.
Put the plug back in again without pressing any buttons. If the machine starts by itself, that isn't an NVR switch.
If you have to press the start button to get it running after the break in power caused by pulling and reinserting the plug (the "no volt" situation) then it is a NVR and is doing what it should - preventing an uncontrolled restart after an interruption in the supply.

Assuming it an NVR you can add as many emergency stop buttons and footswitches as you like in series just by running the live wire through them on the way into the NVR switch or between the switched live and the motor. These switches should be a "Normally Closed" aka NC type and have a momentary pushbutton type action.

If you're in the EU, we use brown to indicate the "live" or "L1" wire. If you use mains flex to wire your extra switches in, you use a piece of BROWN tape or brown heatshrink on each end of the blue wire to show that it's being used as a "live".
Also be sure you use a flex that is big enough to carry the motor current. Look at the existing flex - the cross sectional area e.g 1.0mm2 1.5mm? or whatever will probably be embossed into the outer sheath at regular intervals. Use the same or greater.
If you are putting a new switch in a metal box, use a three core wire and earth the box to the body of the machine. If it's in a plastic box, there's no need to take an earth to it and you can wire the extra switch in with two core.

 

[E-wan]

So if one switch, the machine switch, is NVR additional switches wired in series don't need to be NVR as machine switch would automatically reset and interrupt the circuit in the case of a no volt situation?

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[sunnybob]

There is no point in having two nvr switches in your particular circumstances.

 

[Sideways]

So if one switch, the machine switch, is NVR additional switches wired in series don't need to be NVR as machine switch would automatically reset and interrupt the circuit in the case of a no volt situation?

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That's right. One NVR is all you need.
For the no volt function to work the switches have to be wired in series - if you used NVR switches this would make life difficult as you would have to press all the green buttons at the same time to get the motor to turn on. Nightmare !

 

[E-wan]

Thanks all

Think I know what I'm doing now

Ewan

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