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Member postings for James Hemmingham

Here is a list of all the postings James Hemmingham has made in our forums. Click on a thread name to jump to the thread.

Thread: Fixing motor for Myford Ml7
24/03/2020 21:19:03
Posted by Harry Wilkes on 24/03/2020 15:37:04:


It puzzles me that the original plug says 5A on it, can anyone offer an explanation?

In the olden days they were two sizes of plug the one shown in your pic rated at 5A then there was a larger version of that type of round plug rated at 15A, then with the coming of the ring main 13A became the standard .

Have not read all post's but have you tried disconnecting the motor to see if the fuse blows ?

H


Disconnecting it as in just just unplugging it? I got the motor to start a few times with no load on it with just the 5A, it even failed then though from just being turned on and off a coupe of times.

With 13A is can be turned on and off multiple times but I haven't reconnected the belt to test it under load but i'm hopefully it will be fine. I will just need to investigate the safety side if it works fine.

24/03/2020 21:15:50
Posted by SillyOldDuffer on 24/03/2020 16:02:50:

Posted by James Hemmingham on 24/03/2020 14:34:31:.

...

It puzzles me that the original plug says 5A on it, can anyone offer an explanation?

The round-pin style came in 4 different sizes: 2A, 5A, 15A and 30A.

Before square pin plugs and sockets, UK domestic wiring was wired on a spur system where each socket connected back to a separate fuse. Spurs could be of different current capacities and to stop people burning the house down different sized plugs were used to make sure a 2A device couldn't be plugged into a 30A spur, or a 30A device into a 15A spur. No need for round-pin plugs to contain a fuse because there was one in the fuse box.

The spur system was fine when people only needed a few sockets, but it's inconvenient in a modern home.

In 1947 the system changed to wire houses with ring mains rather than spurs. A ring main can have many sockets connected to it, which suits modern needs. Although the main is protected by a single big fuse, each appliance needs to have a fused plug. All square-pin plugs are the same physical size, but they can be fitted with different fuses as necessary to suit the appliance. I have 1A, 2A, 3A, 5A, 7A and 13A examples, but 3 and 13A are the most common.

A 13A plug and fuse would be OK for a Myford.

Maybe the lathe should never have been fitted with a 5A plug, but not all lathe owners were electricians! Sparey's "The Amateur's Lathe' is well worth reading. Excellent book apart from things like carbide inserts that came later, but his comments on 1950's home workshop electrics make it clear that quite a few chaps back then lived dangerously! It's not a problem though : the wiring and switches etc could all be replaced if necessary.

Dave

That's really interesting thanks. The plug must be ancient.


I have thought I could take the motor to a company near me that do motor refurbishment. I'm a bit worried they fee would be close to that of buying a new motor though. Maybe refurbishment only makes sense if you have something of substantial value to begin with. They might be closed for coronavirus too.

24/03/2020 14:34:31

Thank you for your replies everyone.

It's good to hear it's probably not just a faulty motor, although maybe buying a new one would make life easier with regard to getting everything running safely.

I had read the slow blow fuse type is more suitable too, so perhaps i'll get a 13A one of those.

"One of the disadvantages of buying elderly second-hand equipment is the electrics might well be in poor condition, or not in accord with today's best practice. Damp, damaged, perished, unprotected etc etc. Not a problem because it can be upgraded without fuss, probably adding a NVR in the process. Assuming the machine is a bit dodgy, can the experts advise what James should look for and how he can test for electrical faults? At the moment, for all we know, this old Myford isn't even earthed..."

Thank you for raising this. I will see how far I can go checking it myself, wiring size and earthing, i'll get someone qualified to do whatever I can't. I got the lathe for a good price and have nearly always found the old machinery is better than new unless you are ready to spend a lot, i didn't anticipate the electrics being quite so old.

"What switch gear, Start/Stop/Reevese is fitted?" Nothing, i'll get an NVR fitted.

Simon, thanks a lot for the offer. I'm in Buckinghamshire so it would be a bit out of your way.


It puzzles me that the original plug says 5A on it, can anyone offer an explanation?

23/03/2020 18:46:59

Hello,

I have just bought a Myford ML7 Lathe but the motor has a problem which causes it to constantly blow the 5A fuse.

I reattached most of the wiring as some was in bad condition but this didn't fix it, as a last resort I tried using a 13A fuse and using this the motor seems to work fine.

The original plug it came with was very old with round pins and no fuse inside.

I presume using the 13A fuse is potentially very dangerous though, what do people think?





Thanks

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