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Colchester Student Mk1 Won't Start

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Herman van der Merwe28/05/2020 18:23:40
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128 forum posts
Posted by Richard Kirkman 1 on 28/05/2020 11:10:41:

I've managed for 3 years without compressed air, I don't particularly have the space for a compressor or see the use apart from blowing things.

Air tools are just so much easier to use. Look at a vertical compressor and a separate long cylindrical air storage tank. These fit in two corners or even a corner and just below the ceiling. It is one of those items that once you have it you want to kick yourself for not installing it earlier.

Richard Kirkman 128/05/2020 18:52:26
237 forum posts
512 photos

Okay single phase caps then.

This appears to be the identical model that is in my cabinet.

LINK

I do not want to return it because it was a good deal, and I still need one. I would not find one like this again. If I can get the replacement parts and have them pay for it, that would be preferable. Since if they take it back they'll have to fix it anyway and resell it. Also, it weighs a lot and I don't want to post it back to them, especially since I just broke up the pallet they sent it on.

I have used a VFD in the past for my belt grinder. I want to keep all the wiring inside the lathe and keep it original. A VFD needs to be connected directly to the motor and would bypass all the work that I've put in wiring the lathe back to original (ish) workings. I don't want to use a VFD, it's not for me.

There might actually be one place I could possibly store a compressor. Maybe one day...

Edited By Richard Kirkman 1 on 28/05/2020 18:54:21

Herman van der Merwe28/05/2020 20:31:15
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128 forum posts
Posted by Richard Kirkman 1 on 28/05/2020 18:52:26:

Okay single phase caps then.

This appears to be the identical model that is in my cabinet.

LINK

Excellent price as well! Yes, buy those and then ask the guy you want three matched caps with the test printout to verify the three are a matched set. Me, I would request each cap to be within 5% value of each other. You can even offer him a few bob to do this matching.

Richard Kirkman 128/05/2020 20:36:52
237 forum posts
512 photos

I'm not going to order them just yet or message.

I will wait till I have the wiring diagram or some more contact from the producer of the converter. Because they all might be wrong, it could have had anything done to it.

Those capacitors are just normal motor start capacitors, what were you on about power factor corrector capacitors for?

Honestly Herman, now I'm thinking about looking for an air compressor. Don't put any more tool ideas in my head!laugh

Phil Whitley28/05/2020 21:31:20
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1206 forum posts
145 photos

Hi Richard, Just recieved my parcel!! Thank you so much!! I shall put all this stuff to good use, and I am thinking of something like a DTI, or maybe even a couple of DTI's to go in the beautiful wooden box. I have a couple of Verdict dti's which are approaching the quality of the box, so I may use it to house them! As we used to say in west Yorkshire

Am reet med up lad!

Thank you!

Phil

Herman van der Merwe28/05/2020 21:31:40
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128 forum posts
Posted by Richard Kirkman 1 on 28/05/2020 20:36:52:

I will wait till I have the wiring diagram or some more contact from the producer of the converter. Because they all might be wrong, it could have had anything done to it.

Those capacitors are just normal motor start capacitors, what were you on about power factor corrector capacitors for?

Honestly Herman, now I'm thinking about looking for an air compressor. Don't put any more tool ideas in my head!laugh

Yes, wait for the correct diagram and check the values as per the diagram. You might find that the design called for two running caps and a third starting cap. Who knows? So best get the diagram for us.

Nope, do not make the mistake of thinking starting caps can be used as running caps. A vast difference! Power factor correcting caps or running caps are constantly in use and must be constructed to offer the correct capacitance value under load and operating temperature to ensure the phase angles remain in place.

I actually enjoyed the design of phase correction caps in my first year of engineering studies. Many, many moons ago ...

Well if you have the money buy a vane compressor ... evil grin ... that is on my wishlist ...

Richard Kirkman 128/05/2020 22:23:06
237 forum posts
512 photos

My pleasure Phil. It's nice to give back for once, just to show my appreciation. I wouldn't have got to where I am without you. I figured you'd probably be more likely to use the contactors than me. The sides of the box are some form of mahogany and the top and bottom panel are some really hard stuff that seems like Bubinga, not too sure, but it polishes up nicely. There should be plenty of gasket material there to redo all the gaskets in the lathe or whatever you want to use it for.. I didn't know what drill sizes you had already, but I'm sure they can be used for something. I had some duplicates after buying 2 job lots. I have any size I could possibly need up to 7/8ths pretty much. And still, the mt4 drill that I need to turn the taper down on. I still aspire to make better quality boxes, but that box was a good step in the right direction. I'm sure you'll put everything to good use!

Herman, so are power correcting caps the same as running caps, and how are starting caps different from running caps.

I think I'd have to start off with a small compressor and see how that went. Meanwhile, I think its time to design and make a new and improved 50x1500mm belt grinder. The first iteration just isn't as good as I would have liked it to be.

Herman van der Merwe29/05/2020 07:43:07
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128 forum posts
Posted by Richard Kirkman 1 on 28/05/2020 22:23:06:

Herman, so are power correcting caps the same as running caps, and how are starting caps different from running caps.

I think I'd have to start off with a small compressor and see how that went. Meanwhile, I think its time to design and make a new and improved 50x1500mm belt grinder. The first iteration just isn't as good as I would have liked it to be.

Yes, they are the same IMHO. Here is a very good practical article for your information.

No, do not try to go a small compressor route. You will waste your money as you will want to upgrade in the first week of use. A small compressor is good for blowing dust and maybe pump tires. What you need is one that can give lots of volume, and I mean lots of volume and do this at a minimum pressure of 5 bar. This means you can do all your die grinding, sanding, cutting, drilling, nibbling with it.

Heck, the best belt grinders/sanders I know of are air driven. On my wishlist you will find one.

If you buy old quality pneumatic tools (Chicago, Ingersoll Rand), you can replace the vanes by making your own to fit and also replace the bearings and you have a brand new tool for next to nothing. I once bought a BIG crate full of scrapped air tools for GBP10 and only one of the tools in there I could not fix.

Just one tip. Never ever blow your lathe's ways clean with air. You will force the chips into places where they will cause grave damage.

Edited By Herman van der Merwe on 29/05/2020 07:44:12

Herman van der Merwe29/05/2020 09:34:50
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128 forum posts

@Richard and @Phil, would you please post photos of what the back splash plate looks like where it bolts to the headstock. Mine is all smashed in at this corner and I do not want to bend it to far back as I have no idea as to what it should look like.

Top view, side views is what I am after please.

Richard Kirkman 129/05/2020 11:39:37
237 forum posts
512 photos

Big compressor it is then! (one day)

My belt grinder has a 2hp motor with vfd so I don't think it needs changing to run off air

I'm not too sure what you mean by backsplash plate. My lathe doesn't have one like Phils does.

I received an email back from the man at Danebury electronics.

He said

"Unfortunately we don't keep records dating back that far.

I would replace capacitor values like for like.

My best guess for capacitors if they are unidentifiable are

Run capacitor 60uf 450V

2X start capacitors 80uf 450V.

Broyce relay set to around 275V"

So it looks like the capacitors in there are correct, but they still all need replacing.

But, from what I found on the 80uf capacitors on eBay, they were motor running caps not start ones. So I'm a little confused once again.

Phil Whitley29/05/2020 18:38:31
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1206 forum posts
145 photos

here ya go Herman!

Herman van der Merwe29/05/2020 20:15:42
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128 forum posts

Thanks @Phil, so I see the side plate is all straight with the last bit into a lip. I have a lot of panel beating ahead of me!

Herman van der Merwe29/05/2020 20:20:51
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128 forum posts
Posted by Richard Kirkman 1 on 29/05/2020 11:39:37:

But, from what I found on the 80uf capacitors on eBay, they were motor running caps not start ones. So I'm a little confused once again.

Just buy the running caps. They are "stronger" than starting capacitors and obviously costs more but will be a lot more stable.

Herman van der Merwe30/05/2020 16:18:30
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128 forum posts

Can you guys please post a picture of your lathe's apron? Not your kitchen one please

We are trying to figure out what apron my funny lathe has and how it works.

Richard Kirkman 130/05/2020 20:30:25
237 forum posts
512 photos

I've made a little bit of progress with the traveling steady. Still getting better at painting, but I'm getting there. Sprayed it for the first time today, it gives a much better finish, I'm amazed, even with a wagner fence and decking sprayer. I just wish I had sprayed the primer on with it too! The finish could still do with improvement, but I'll sort it somehow.

I think painting more things at once would be much better, so I might move onto doing a few lathe parts soon. I can feel the tailstock calling to me

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Pictures and video of apron

img_20200530_194133.jpg

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Video Link

Herman van der Merwe30/05/2020 21:13:53
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128 forum posts

Paint work looks good! Keep hacking away at learning how to paint and then you will hit the wall ... you will need a quality compressor ..

Thanks for the photos and the video. Seems like my lathe is missing the lockout arm thing. I will double check tomorrow if it maybe is not laying somewhere, but I doubt it.

I see your one gear is as bad as my lathe's! One day when you strip, clean and paint the apron you can take measurements of the lockout arm thing for me.

Thanks again @Richard!

Herman van der Merwe01/06/2020 08:00:09
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128 forum posts
Posted by Richard Kirkman 1 on 30/05/2020 20:30:25:img_20200530_194337.jpg

Morning @Richard. Would it be possible to take some more pictures of the bolt thingy that holds the lockout arm in place?

I found a photo with dimensions on the Colchester groups.io page as below. Would it be possible to get something in the apron from underneath to check the length and possibly the width of the lockout arm against the sketch's dimensions?

Richard Kirkman 101/06/2020 12:20:10
237 forum posts
512 photos

More pics here. I don't think the thickness of it matters too much as long as it fits in the slots that are on the lead screw bit. As yours is in pieces i'm sure you can measure the slot and other parts. I can get even more pictures, but I think I've covered most angles that I can get to it

Just to be clear, my apron is shown in the manual that I sent in somewhere. So that's the place to look

i can't get a full measurement but the measurements from the picture seem right to me.

img_20200601_115601.jpg

img_20200601_115631.jpg

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img_20200601_115732.jpg

Look carefully at the shaft it's resting on, there's a flat.

I've emailed the company I bought the converter from to ask if they'll pay for the capacitors, but their website is no longer available and their Facebook has shut down. Perhaps they have closed down. Either way I'll get new capacitors.

Herman, is there any requirement to use the same brand, or am I okay to buy these cheaper ones that are unbranded. Surely they're the same? They have all the same codes on, yet they're much cheaper

Cheaper Caps

 

Edited By Richard Kirkman 1 on 01/06/2020 13:07:43

Herman van der Merwe01/06/2020 20:18:20
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128 forum posts

Hi @Richard! Thanks for the detailed photos. These are really helpful!

Re the caps. I think we need to backtrack a bit here. Something does not feel right after I have read your whole thread again.

Your RPC needs to be designed to work with your electrical motor installed. Did you do that or did you simply match the lathe's motor to the RPC's output voltage and kW rating and bought the RPC based on those two parameters?

I brushed up on my RPC knowledge and you will need:

1. Two running caps rated at at least 370VAC or higher

2. One starting cap to start the idler motor rated at at least 250VAC or higher.

3. There must be some form of disconnector to disconnect the starting cap after the idler motor has started. You will need to find this and determine what it is. I can be a relay, a timer, a bimetal heat based switch.

4. Overload protector to protect the RPC if it is still running and the mains power goes down and comes back up again while it is still running. I think the orange box is wired for this but not sure.

The values of the caps will depend on the type of motor you have installed in the lathe. It looks very old, so I doubt if it is a squarel cage or induction motor.

So you will need to post the specification plates of the lathe motor and the idler motor of your RPC for me.

Then you need to let me know the type of disconnector in the RPC and the specifications thereof.

You will also need to make yourself a cuppa of whatever you drink and trace and draw the RPC's wiring as it is in the big blue box at the moment. In other words you will reverse engineer the existing circuit and produce your own wiring diagram which we can then analyse and check for compliance to your needs.

Lastly the best place to buy your caps would be https://www.surpluscenter.com/Electrical/Capacitors/Motor-Run-Capacitors/ and https://www.surpluscenter.com/Electrical/Capacitors/Motor-Start-Capacitors/ (Not that I know the UK that well, but this is a know source for quality equipment at good prices)

Once we know the details of what we have in place we will have to design the cap values around these. I am very rusted on this as I studied and used this many many moons back when the moon was still blue ...

Herman van der Merwe01/06/2020 20:32:03
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128 forum posts
Posted by Phil Whitley on 25/05/2020 20:48:02:

Evening all!, well I was right, I haven't got the holes, or the threads, I have two bolting down holes without threads at the headstock end, and one,central, at the tailstock end

The hole that you guys have in the cupboard at the front of the lower shelf is not there on mine! Don't bother with the measuring Herman, it is sitting firmly on a level floor, and it is staying where it is until after I have replaced the spindle bearings and then do the alignment!

Phil

Edited By Phil Whitley on 25/05/2020 20:48:57

@Phil, while I was searching for details about the apron lockout key thinghy I read that your lathe must be fitted with leveling pads. These fit from the bottom of the holes and you adjust the nut on the pad's threaded rod to get the lathe level.

I would recommend you buy machine leveling pad with the ball joint in the top of the pad which allows the threaded rod to enter the lathe exactly perpendicular to the lathe's bottom plate.

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