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Stent T&C Refurb (also need Wiring Help)

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Colin Heseltine14/06/2020 17:31:55
481 forum posts
146 photos

I bought a second hand Stent T&C many years ago and finally during lockdown have had chance to strip and clean it, paint it and do a few minor mods.

As obtained although the handles/wheels were graduated but the main pillar base, table end clamps nor spindle mounting were graduated. I wanted to get this done.

I had recently completed a Division Controller and using this in conjunction with a Hemingway Graduating Tool was able to do the graduations. Had to make several mods to the graduating tool to enable it to be used on the milling machine.

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hem3.jpg

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stentrefurb1.jpg

I still have to make a better grinding wheel guard than that which the machine came with. When did a test run I realised that grinding wheel is running in a clockwise direction and thus blasting the sparks up at my face.

I would like to make the to be able to run either clockwise or anticlockwise. I have shown below the motor plate and then the inside connections to the motor and also the wiring schematic from the motor. I have followed this with a hand drawn layout showing the various cables and colours.

stentmotorplate.jpg

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stentmotorwiring.jpgAs I understand it I can run the motor in either direction by moving the two links plates; currently Z1 to U2 and Z2 to 02 to a revised state of Z1 - 02 and U2 - Z2.

I want to be able to do this by means of a 3 position switch, Left=Anticlock, Centre=Off, right = Clockwise.

Can some of you considerably more expert members please advise on type of switch and how to route the cables. This would be greatly appreciated. I do not have a problem doing the wiring I just do not want to screw it up and blow up a nice motor..

If any of you fine gentlemen have a Stent T&C in your workshops I would be interested in knowing what size grinding wheels you use and how far they reach towards the table. In the picture I have shown of the Stent with some of its accessories you will see a bracket on the right hand side of the picture to the right of the pair of castings (next on the list to machine) do you have any idea what this is. It does not appear to relate to any of the drawings in the plans but could possibly be for putting a radius on a cutter?

Many Thanks

Colin

Colin Heseltine14/06/2020 20:25:34
481 forum posts
146 photos

Possibly answering my own question here, but would still like some confirmation.

I think I need a Double Pole Double Throw Toggle switch with a centre off position rated for 250v and I would guess about 5 amps.

Would connect Z1 to one input and Z2 to the other input. With the switch set to position 1 the output from Z1 would go to U2 and the output from Z2 would go to 02. This would give anticlockwise running.

Switching to the centre position would break the connections. Moving switch to position 2 would connect Z1 to 02 and Z2 to U2. This would now run the motor in clockwise direction.

I noticed in the motor schematic it shows Live to U1 and Neutral to U2. My motor is set to reverse of this but I guess this does not matter too much??

I have looked on RS Components but not seen a suitable DPDT switch.  CPC Farnell Have a Toggle Switch, Metal Lever, DPDT, ON-OFF-ON, 10A   Part No SW02434 which I think would be ok.

My other thoughts would be that it would pay to fit a NVR switch on the incoming supply.

Colin

Edited By Colin Heseltine on 14/06/2020 20:37:29

Martin Cargill14/06/2020 20:46:10
148 forum posts

You have answered your own question correctly. A Double pole Double throw toggle switch with a centre off will do what you require. All you have to do is to wire a crossover at the switch (feed the Z1,Z2 to the two centre contacts and wire cross over links between the two pairs of outer contacts and then wire the start winding  to one end of the switch. I assume that the switch shown in your diagram is a centrifugal one to cut out the start winding once the motor has spun up, if so then you don't need to worry about the switch being changed over when the motor is running as the start circuit is already switched out at this point. The motor will only start in the opposite direction once the motor has stopped and has been re started.

Suitable switches can be found on Ebay

A NVR on the incoming supply is a good idea as it protects against an inadvertent restart if the power supply is interrupted.

 

Martin

Edited By Martin Cargill on 14/06/2020 20:50:06

duncan webster14/06/2020 23:38:45
avatar
2858 forum posts
32 photos

Why do you need a centre off position? If you have it in the off position and then energise the main on/off switch it will buzz for a bit then get hot as there will be no back EMF..

You can get a double contactor affair which acts as NVR and reversing switch, my lathe had one before I converted to 3 phase. Probably stunningly expensive.

peak415/06/2020 00:25:07
avatar
1268 forum posts
146 photos

I wired my Quorn with a DPDT toggle for forward/reverse, and a cheap NVR switch from ebay for stop start.
Because I move the grinder around, I also used a kettle socket and detachable lead, to save tripping myself up when I get old and doddery.
It also means it's likely to unplug the lead if I accidentally catch it on something, rather than dragging the grinder off the bench.
This makes it a particularly good idea to use an NVR switch to save accidental re-starts.
It also helps avoid trying to reverse the motor by accident when it is still spinning down, which is the danger with a centre off toggle.

Bill

Colin Heseltine15/06/2020 09:48:23
481 forum posts
146 photos

.NVR switch and a DPDT switch without centre off will be ordered asap. Thank you for your helpful comments.

Colin

thaiguzzi15/06/2020 11:15:25
avatar
702 forum posts
131 photos

Welcome to The Club.

The Stent Owners Club.

Bought mine as a S/H unfinished project too. Funny old world. Innit.

Yeah, i built my Stent using a S/H washing machine motor with a new external capacitor, as i knew washing machine motors have to run both directions.

Double toggle switch is from a Brit motorcycle, so originally 12V.

Never been any elektrickery problems.

Got over 200 hours of build time in it, and at least half that in use.

Happy playing.

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Colin Heseltine16/06/2020 08:53:56
481 forum posts
146 photos

Amazing how different they all look. You look well tooled up for it.

Colin

thaiguzzi17/06/2020 10:22:49
avatar
702 forum posts
131 photos

Yes, i did'nt like the look of the motor plate design in the Stent drawings and others on the web, so changed how my motor was bolted on, adjusted, and the Z column.

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