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Stop buttons

Staple balls - 3/6/15 at 07:06 PM

Right, being a good, responsible adult and all that, I've let the kid buy himself a bandsaw

Anyway, I'm thinking that it might be a good time to also get some of the emergency stop buttons and dust them lightly over the garage, as I'd rather not lose my knackers because he's had some neural lag.

So, I'm thinking of putting some oh-crap switches into the electrics as a whole for these situations, am I right in thinking I could just wang 3-4 of New AC 660V 10A Emergency Stop Push Red Sign Button Switch Control Waterproof in series before all the plug sockets and any one of them will stop everything plugged in downstream?

HowardB - 3/6/15 at 07:13 PM

I would say so,.. good idea too.... I might get some

bi22le - 3/6/15 at 07:22 PM

Only 10A though but your correct in your thinking.

trextr7monkey - 3/6/15 at 08:06 PM

Axminster Tools do a short extension lead with a single outlet and stop button so you can keep it close I have one on router table as well as band saw
Hth
Mike

SteveWalker - 3/6/15 at 08:51 PM

A better way would be to put a contactor in the mains feed to the garage sockets, put all the emergency stops in series to break power to the contactor's coil, but also put a spare normally open contact of the contactor in series with the emergency stops, with a "reset" pushbutton in parallel with that contact. Then pushing a stop button or the power going off will drop out the contactor and it will not reset until the stop button has been released and the reset button is pressed. Once the contactor has closed, its normally open contact will then hold it energised when the reset button is released.

This gives the advantage that releasing the emergency stop will not allow equipment to accidentally restart without a further action and it also acts as a no volt release. If equipment stops due to power failure, nothing will restart when power is restored.

This is basically a simplified version of a typical industrial setup.

[Edited on 3/6/15 by SteveWalker]

Staple balls - 3/6/15 at 09:27 PM

That sounds utterly overkill, I like it

tegwin - 3/6/15 at 09:47 PM

Assuming you have a fast acting RCD in the consumer unit.... can you not simply have a switch which shorts N and earth? That would fire off the power pretty damn quickly and would need to be reset before normal service could resume?

daniel mason - 3/6/15 at 10:00 PM

They are supposed to/ recommended to stop the motor completely within a set time!

SteveWalker - 3/6/15 at 11:17 PM

quote:
Originally posted by Staple balls
That sounds utterly overkill, I like it

Nah. If I was going for overkill, I'd have suggested at least two pole switches, 24V dc power supply, safety relays, line resistance monitoring, twin safety contactors and failure warning lamps/audible alarm, so if any one thing failed, the whole system would still work safely and warn you of a fault! That's the sort of thing that I've looked at in the past for work.

907 - 4/6/15 at 06:29 AM

IMHO the most important thing with a stop switch is where it is positioned.
No point in fitting one if in your moment of blind panic you can't reach the bu**er.

My lathe for instance is brilliant. Its on the front at knee hight.
If your jumper got wrapped round the chuck you could bang your leg against the button
as your hands would be trying to rip what remains from the machine.

I have a pedestal drill with a button you can nut.
When one hand is holding the quill lower and the other is hanging on to that two foot lump
of angle should the drill jam in the hole, nut the button.
Foot operated are good as long as your drill is floor standing.

My band saw has one on the arm. lay across the machine and you will switch it off.

The test is; can you put your hands in your pockets, and still switch it off ?

HTH
Paul G

hizzi - 4/6/15 at 06:31 AM

the stop buttons need to be after the socket but before the appliance. if you put the stop before the socket and your garage is wiring correctly with a ring main the circuit will still feed from the other direction

Staple balls - 4/6/15 at 07:03 AM

The garage is not wired anything approaching properly, it's wired more like it's all one extension lead plugged into the kitchen.

Rented house with a bar steward landlord, so it's not worth the time and money for me to fix it.

motorcycle_mayhem - 4/6/15 at 12:06 PM

If you've bought the smaller of the two Clarke bandsaws, I could see the need. Stop switch isn't too useful for an emergency.

I've just used mine vertically to cut two wing supports for the F3, 6mm H30, so easy to see a finger getting caught.

Staple balls - 4/6/15 at 12:41 PM

He managed to pick himself a burgess/record BK3 up with a sander thing on the side, (don't even ask me how a 13 year old can convince someone it's a good idea to sell him a bandsaw)

There's only one switch and depending where you are around it, it's utterly inaccessible (especially if you're short) I'm thinking it might be best to build it a heavy table with a stop switch or 2 on it, so he doesn't have to reach to use it, or stretch over it.

Nice project for the weekend methinks.

AntonUK - 4/6/15 at 06:24 PM

I wish my Dad would have let me have a band saw at 13... i was 20 before i got a grinder... and when I was 25 he still wouldn't let me near the chainsaw.

Staple balls - 4/6/15 at 09:41 PM

Mostly I'm working on the logic that an enclosed blade that doesn't go anywhere you don't expect it is pretty safe, So I let him at the bench grinder, pillar drill, (in the near future) bandsaw, and he's handy enough with a gasless mig and sanders etc, hell, he can use the angry grinder with anything but a cutting disc on.

Saying that, no jigsaw, angry grinder with cutting disc, no reciprocating saw, no chainsaw, no table saw and no frigging strimmer (but yeah, 30 year old 2stroke monster, not safe for human consumption)