Bringing an old Robot back to life - Surface Grinder.

[Techo1]

Dean, a friend that I worked with had a roll of tape and the proper varnish from the electrical shop at Australian Airlines where he worked, I was in the machine shop. You can get air drying varnishes for this purpose which are probably just as good these days.

Are you sure that the 4kw VFD will run your motor?

Lex.

[Oldneweng]

Dean, a friend that I worked with had a roll of tape and the proper varnish from the electrical shop at Australian Airlines where he worked, I was in the machine shop. You can get air drying varnishes for this purpose which are probably just as good these days.

Are you sure that the 4kw VFD will run your motor?

Lex.

The manual says the motor is 7 ^_1/2 / 3 ^_3/4 HP option.

I am guessing this means 7.5 for high speed and 3.75 for low speed. It is also my understanding that this is a somewhat high powered motor for a lathe of this size. I have seen similar sized lathes with much smaller motors. Maybe these have a clutch tho.

All in all it is my guess that I am not very likely to need that much horsepower for what I want to do. If I am not right about this then that means I am wrong.

Dean

[Ueee]

Hi Dean,
Don't want to hijack Lex's thread but i would just hood it straight up to the 7.5hp windings and leave it at that. You should still get about 4 HP out of it, should be enough and you don't need to worry about fishing out the star point. 4hp should be more than enough, the Antrac on low speed has 3.75hp (6 pole, 5hp 4 pole for high), i can take 4mm deep cuts with carbide no worries.

Ew

[Oldneweng]

Hi Dean,
Don't want to hijack Lex's thread but i would just hood it straight up to the 7.5hp windings and leave it at that. You should still get about 4 HP out of it, should be enough and you don't need to worry about fishing out the star point. 4hp should be more than enough, the Antrac on low speed has 3.75hp (6 pole, 5hp 4 pole for high), i can take 4mm deep cuts with carbide no worries.

Ew

I would be happy if that is the case Ewan. When I started a thread about this lathe there was a lot of doubt whether the motor would be suitable as it stands. All I want to do is get it running. I am sure it will have more than enough power for me.

Dean

[WCD]

... You can get air drying varnishes for this purpose which are probably just as good these days.
Lex.

Hopefully this (Buy Electronics Varnishes & Lacquers RS Clear 250mL Can, Electronics Varnish & Lacquer, 60kV/mm RS ERMR8008B250ML online from RS for next day delivery.) would do the job, because I bought a tin to use for a motor star point extraction job.

Cheers,
Bill

[Techo1]

As mentioned earlier in this thread, I have been working on fitting an electric clutch to allow the feed mechanism to be disconnected when not required. This has been a very time consuming process which may or may not prove to be a successful modification in the end.
The photo's show the clutch mounted on the feed mechanism input shaft housing.





Lex.

[Com_VC]

Hi,

When you connected the 3 additional wires for the star connection what type of wire did you use? Is there a special type of wire for this? I suppose would need to handle the heat.

Thanks

[jhovel]

Now you are talking my language!
Can you tell me a bit more about how you are going to go about driving your table?
I was thinking about a similar mod for my B&S grinder, but have thus far not come up with a good solution - but you have, I think!
I've bought a very small 1/3 HP VFD (Siemens) that I intend to use to drive the table back and forth - triggering the direction reversal with limit switches - sot start and stop of course.
I'm all ears as to your solution. BTW, my B&S is all manual. I'm also looking for an idea for table feed - ratchet or whatever.....

[Techo1]

Yes VC, I had some high temp wire, left over from a furnace project, that was about the right gauge.

Joe, the clutch was my idea, the rest of the automatic feed mechanism is original "Robot" as shown in earlier posts in this thread


Lex.

[Com_VC]

Do you know the proper name of the wire. I'm trying to track some down to convert a motor.

Thanks

[Ueee]

There are links to a couple of different hi temp wires in a thread called making a heat treatment oven that I started a few months ago. I would give you a link but I'm on my phone....

Cheers,
Ew

[Com_VC]

cheers just found it Should be plenty.

Heat Resistant 2 5mm Fibreglass Wire Cable High Temp Cater Spares 5 Meter | eBay

[Techo1]

Do you know the proper name of the wire. I'm trying to track some down to convert a motor.

Thanks

I have seen the same type wire that I used in electric stoves, if you can find an old one you could strip the wire out of it.

Lex.

[Com_VC]

cheers for that. I just found some old down light fittings and it has a multicore wire with a braided cover. It looks about right to me

[Techo1]

The electric clutch modification is not quite finished but I was able to try it out today and it works very well.



The new idlers mounted on an eccentric shaft for belt adjustment.



6 groove drive pulley shrunk onto where original flat leather belt pulley was mounted.



Switch mode power supply from China, not ideal for this type of load but seems to work OK.



Regards, Lex.