Cable Gland

Emgee

I have to admit the cables as shown in my schematic sketch were copied as a result of someone connecting the starter to the motor and actually had it running.

You will see the incoming live is connected to terminal 1 L1 and not A1, having said that I really do appreciate what you are saying about the schematic diagram inside the cover, so heaven knows how it ran and switched off.

I fully understand the workspace envelope required for woodworking and when I need to use my radial arm saw now only do so when I can wheel it outside. I'm not sure though whether your current plan is going to be as convenient to operate as you expect.

In normal parlance, 'Emergency Stop' switches are just for that purpose. Using four separate ones just to stop the machine without having an equally easy to operate 'On' switch is highly unusual (or at least I have never come across a setup like that).

Some general thoughts (on this particular) machine control.

Feeding the motor through a contactor (as you are planning) then gives the No-Volt release feature that nowadays seems to be mandatory so that good.

The contactor should have a low voltage coil so that all the control wiring (some of which we now know needs to be flexible and frequently moved) is isolated and would not cause a hazard if it got damaged, tripped over, fell iunto a bucket of water, or whatever.

Only three low voltage wires (which would not need an earth) are needed to connect to two pushbuttons that would be the On/Off controls for the motor. If the Stop button is the larger or more prominent button of the pair, then in effect it is your E-Stop. You can have as many two button pairs as you want from the same three wires if you want to control the motor from several locations.

The more switches and controls you have, especially if they are widely dispersed the less likely one would be to instinctively know which one to use in a genuine emergency.

If this machine has approximately a 'square' format like a large table, then just two E-Stop switches or control positions on diagonally opposite corners are just as reachable as your four will be.

Other options to consider could be, a keyfob type wireless control of the motor maybe on your hand or wrist whilst working, foot operated switches (that need to be kept depressed).

Ian P

On some of the overload relays/trips the red button can be configured to auto reset or manual reset. I can’t remember if your type of DOL has this but if your using this to stop the machine there won’t be be a problem with having to manually resting the trip or by using any of the E-Stops (hope that makes sense 😳

Good point Emgee regarding the control coil A1 connection - it may be connected - it needs to be checked so that the contactor does ‘holds in’ when starting.

John

P.S.. Looking at the photo I think the red needs to be linked across NO to A1 that comes from the push button. So that the coil holds in once your finger is removed from the on button. 
Disclaimer: I can see the top of the connector block. 😳

Edited By Johnboy25 on 25/02/2020 15:05:12

Johnboy

" Good point Emgee regarding the control coil A1 connection - it may be connected - it needs to be checked so that the contactor does ‘holds in’ when starting".

I have to admit I haven't got a clue how to test it.

Thanks again

Clive

Guys

Could the coil A1 be already connected internally, all I know is the motor ran and switched off with it wired as shown on my sketch.

I’ve got so much doubt in my mind I think I’m going to bring the E/stop cables into the old original switch box on top of the motor and because I’m way, way out of my depth and at this stage in the game I’ll get a qualified electrician in to do all the connections, including connecting up to the DOL starter.

Needless to say, I will certainly make a sketch and photograph how it’s been done and if anyone’s interested, I can post it on the forum.

I hope none of you have developed too much cramp in your fingers from all the typing youv'e done in replying to me , and thank you all once again for your views and help. It’s been very much appreciated.

Clive

Clive if it’s ran before and you can switch of either by the stop or E-stop - you must be pretty close to finishing it.👍Don’t give just yet! I don’t know how far you are away from me but if your local-ish I’d happy to pop over to check it out. If not you could PM me with a short video?

John

p.s. If you don’t ask you won’t learn by your endeavours

Edited By Johnboy25 on 25/02/2020 16:02:26

John

Thank you for your kind offer of popping over, sods law I'm in Stafford light years away from you.

No doublt I'll be charged an arm and a leg for the job, but I don't want to get a belt off something even though the whole of the house wiring is RCD and RBCO protected.

Thanks again

Clive

Ian P

Sorry I must have missed your last posting, but having read it as I’ve already said this is getting way over my head, foot switches, key fobs plus all the cost of it.

I’m retired and sadly don’t have the Duchy of Cornwall or Lancaster to finance me, pity .

I suppose at the end of the day that’s why I’d thought I’d have a crack at doing it myself, all I can say is at the moment I’ve got a machine I can’t use, maybe I should have stuck to reaching over to turn it on and off.

Indecently I’ve got a compound sliding mitre saw much the same as yourself I can only use it if it’s not raining.

Its big, the depth of cut 111mm and width of cut 343mm, thank heaven I don’t need to wire a DOL or emergency stop button to it.

It looks as though I will have to start trawling the net for my local sparks

Thank you for taking the time to try and help me

Clive

Edited By Clive B 1 on 25/02/2020 19:06:44

Edited By Clive B 1 on 25/02/2020 19:08:01

Your push to stop buttons I hope they all have a reset control otherwise once you release when operated the machine will restart , This is not what you require as a Emergancy stop or push to stop is just that Machined stopped. . Supply to Machine Starter control relay coil has been broken , Machine will not start untill the problem or reason has been been corrected.

I solved this problem on my saw bench by fitting 2 way switching on each side of the bench.

Your question on earthing asumeing the complete machine is metal everything will bond through the metalwork.

Brian Morehen

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