Electrical Help Needed!

[Dieselman 63]

Hi,

I'm thinking about buying one of these for a drill press I've got coming to my workshop.

http://nz.rs-online.com/web/p/emergency-stop-foot-switches/4107060/

We used to have them at school and they were fantastic. My question is how would I set it up? Is it something that just attaches to the wire going to the plug or is there more to it?

Cheers

 

[daleyd]

You'll need some sort of control relay to use one of these, they aren't really designed to operate directly on the motor if you are using direct from a switch.

 

[rtbcomp]

They're rated at 10 amps, 500v AC

How do you want it to work? Press to stop or keep pressed to allow the drill to run? Does the drill have a starter with a no-volts release fitted?

If you can arrange a footswitch to control the coil in a starter you should be able to get away with a cheaper unit.

 

[daleyd]

The issue isn't the electrical rating - the one linked to is momentary so if you push on the pedal the drill will stop. When your foot comes off it's going to start again. (Or vice versa depending which way you wire it, but either way is not really suitable).

If you don't have an NVR/contactor then a latching e-stop button can be used.

 

[rtbcomp]

^^ that's the idea, keep your foot on to keep the drill running and have an NVR starter AFTER the footswitch. The procedure would be press the footswitch, press the start button, drill the hole then press the stop button and release the footswitch, that way the footswitch doesn't actually switch any current, or release the footswitch and the NVR trips.

If you can get to the coil connections on the NVR starter, then a lower rated (and cheaper switch) could be used to switch the coil.

In an emergency lift your foot, the NVR trips out so you can't restart without performing the above procedure. You do need an NVR starter though. You could use an NVR emergency stop button after the footswitch so someone else could stop the drill if the footswitch jammed. The NVR is the inportant bit, a latching e-stop button may not be so equipped, so make sure you get one that is.

 

[daleyd]

Yeah, but going by the first post "Is it something that just attaches to the wire going to the plug" to me doesn't suggest there's any other sort of control. Without any further info on what's already there then I'd say no, it's not suitable - at least not without further clarification.

That's of course not saying it wouldn't be suitable with the correct bit's around it, but it's not going to wire into a standard drill press with just an on/off switch.

 

[Dieselman 63]

Yes, I don't want a dead man's pedal like the tube drivers have (or had? Not sure if it's still a thing anymore). Basically something I can kick which would kill the power and return the switch to the off position, but wouldn't require any buttons to be pressed before restarting. It was a passing thought, if I could do it for the $130 listed I would, but I have a very limited understanding of electronics so building a system would be hard for me.

 

[daleyd]

What you want is certainly do-able, but would require some extra bits and a bit of wiring. As rtbcomp says you will need an NVR (No Volts Release) for this to work. It's not hugely complicated though if your not overly confident with electrics then it probably seems it, but as a fist step you need to work out what you have already and go from there.

 

[rtbcomp]

If you have an NVR starter on the drill you need to use the normally closed (nc) connections on the footswitch, press the "on" button and the drill will start, if you then kick the pedal the drill will stop as the NVR trips out. Take you foot off the pedal and press the "on" button again and away you go.

Using the normally open (no) contacts on the footswitch will give you a dead-man's handle.