Old Singer sewing-machine Wiring !

[Michael GilliganParticipant @michaelgilligan61133]

It seems barely appropriate to put this in “Electronics” but I think it worth sharing.

Three short but informative blog-posts about electrical safety:

https://oldsingersewingmachineblog.com/2011/11/06/electrical-safety-and-old-singer-sewing-machines-part-one/

Part One includes hyperlinks to the others

MichaelG.

[GeorgineerParticipant @georgineer]

I’ve just gone through this minefield when rewiring a 1960s Singer machine (model 120k if memory serves).  There’s an awful lot of confusing and contradictory stuff on the interwebs (said he, trying not to sound surprised) so I went back to first principles.

For that particular model I concluded that the construction of the electrical components, which form a self-contained unit, could safely be treated as class 2 so I wired and tested it accordingly.  I have upwards of 50 years electrical engineering experience, and am PAT certified.

There will now be a short intermission while the barrack-room lawyers marshal their arguments.  I’ll let you know how things went after I’m released from chokey (if they can find me a room to share with all these rioters).

George

[Martin of WickParticipant @martinofwick]

So what exactly is the issue here?

Old electrical machines with old electrical wiring backed up by decades of unqualified molestation and bodgery are a potential hazard?

Well who knew!

(situation also applicable to old houses, cars, aircraft, workshop equipment etc. etc.)

[OldironParticipant @oldiron]

If the health and safety brigade were alive during the industrial revolution we would still be in the dark and using small children to clean chimneys. (now there’s a thought)

[Martin of Wick]

On Martin of Wick Said:

So what exactly is the issue here?

 

[…]

< sigh >

There is no “issue” here Martin

It’s a forum … people share things that might be of common interest.

MichaelG.

[Georgineer]

On Georgineer Said:

…  There’s an awful lot of confusing and contradictory stuff on the interwebs (said he, trying not to sound surprised) so I went back to first principles.

For that particular model I concluded that the construction of the electrical components, which form a self-contained unit, could safely be treated as class 2 so I wired and tested it accordingly.  I have upwards of 50 years electrical engineering experience, and am PAT certified.

…

George

Well George, though 50 years experience and being PAT certified inspires confidence, neither guarantees anything.  Might even inspire unjustified over-confidence.

I hope all is well, but just to put my mind at rest, could you have another go at explaining what defines Class 2?  Difficult for me to see how a metal Model 120 Singer could ever be Class 2.

Barrack Room Lawyers are harmless, it’s real lawyers you need to worry about!  No joke being held accountable by a court if someone is injured by a negligent repair.

Dave

 

[Martin of WickParticipant @martinofwick]

Sure old singer machines are class 2, unless the little bit of oiled paper separating the live wires from the metal covering to junction box has fallen out or rotted away with time. Always a good idea to replace the flaky paper with a little box of PET or other insulator.

motor case / junction box is (usually)  bakelite = insulation + Wiring is insulated = 2 independent modes of insulation.

I doubt that is the official definition of a class 2 appliance, but it seems to be the way modern manufactured goods  approach the issue most of the time.

Sure beats the hell out of my IKEA wall lights that have just a chocolate block connecter screwed directly to the metal no earth and no further containment of the electrical connection.

We expect old stuff to be higher risk when it is the new, supposedly compliant stuff we have to beware of. Increasingly, compliance means exactly what the manufacturer wants it to mean, nobody is sufficiently curious to check (but if they do, whaa!… the nanny state, health and safety gone mad etc). Until the inevitable happens, and then you get the lawyer-fest.

 

 

[Robert Atkinson 2Participant @robertatkinson2]

It can be hard to identify why a particular item meets (or does not meet) Class 2 “double insulated”. Even someting as simple as a lamp.
Basically there must be either two layers of standard insulation or a single layer of reinforced insulation between any live part and the user or a conductive part the user can touch. Ther are also conditions for gaps and surface distances that the electrons could jump or get conducted across (clearance and creepage).
If the old Singer electrics are totally enclosed in bakelite or similar and any connector are arranged so thano live pins can be touched wheh unplugged (or plugged in just to cover the odd smartarse). The only likely failure point would be winding to motor spindle. If the motor end of the belt is under a cover then that is OK.
If the home is modern with an RCD that is an extra layer of protection. If not you could consider fitting a plug with an RCD e.g. https://www.screwfix.com/p/masterplug-13a-unfused-plug-in-active-rcd-plug/44855. Either will give an extra level of protection.
Remember that unless it is damaged or obviously unsafe you don’t have to bring a item up to the latest standard.

Robert.
Yes, the one who has been accused of being H&S police….

 

 

[Michael GilliganParticipant @michaelgilligan61133]

Now that we have a discussion going … I would just like to mention that [whatever the modern implications might be]  Singer stated very clearly that the wiring should not be earthed.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

This page might be of interest … there are some downloadable booklets which include wiring diagrams:

https://bobsvsmservice.com/manuals-i-mention-in-youtube-videos/

 

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

For the odd few who may still have an interest in using these [or similar] motors … here’s a video about lubricant:

https://youtu.be/4OcjbkejY_0?feature=shared

MichaelG.

.

You will hopefully already be aware that Oil should not be used.

[Michael GilliganParticipant @michaelgilligan61133]

A little more detail:

https://youtu.be/otAj5FrGKZw?feature=shared

MichaelG.

[Michael Gilligan]

On Michael Gilligan Said:

Now that we have a discussion going … I would just like to mention that [whatever the modern implications might be]  Singer stated very clearly that the wiring should not be earthed.

MichaelG.

Yes, the electrics of Singer’s early machines are very simple, and have no provision for an earth.  Made sense at the time, before the UK standardised on 240V 50Hz, when power was provided in some local voltage in AC or DC.   I’m fairly sure Singer’s early electrics pre-date Class 1/Class 2 safety requirements, and would not be acceptable in a new machine today.   As older machines are made of exposed metal, they should be earthed – just like a lathe.

Robert gives a good explanation of why these old machines aren’t Widow Makers.   Briefly,  Singer went to a lot of trouble to isolate the motor from the machine.   The motor is enclosed in a Bakelite case, and it drives a rubber belt with a Bakelite pulley.   Not easy to be zapped by one.

But what happens when someone changes the Singer motor for a different type?  The modification could break Singer’s safety system, for example an ordinary metal cased motor will probably connect electrically to the machine through the mounting bolts which the Singer motor doesn’t permit.   Thoughtlessly substituting a new motor is risky because it may not meet modern requirements or Singer’s original design!

I’ve failed to identify George’s machine.   A careless search for Singer 120K misled me into thinking it was a pre-war type, but George said his dated from the 1960s.   Now I think the Model number is misremembered, making it very difficult to comment!   Later Singers meet modern electrical safety standards, so a 1960s machine is likely different from something designed before 1910.

I’ve also failed to find a description of how Class 2 has changed over the years.  ‘Double insulated’ is difficult to define technically so I guess Class 2 had to be beefed up a few times after accidents exposed loopholes in the early versions.  Class 2 is not solid ground!  In contrast, Class 1 doesn’t seem to have altered much, probably because ‘earth required’ is relatively simple.

Dave

[SillyOldDuffer]

On SillyOldDuffer Said:

[…] I’ve failed to identify George’s machine.   A careless search for Singer 120K misled me into thinking it was a pre-war type, but George said his dated from the 1960s.   Now I think the Model number is misremembered, making it very difficult to comment!   […]

For any insomniacs, here’s some free entertainment:

https://archive.org/details/manuals_singer

… by no means exhaustive, but a good start.

MichaelG.

[Michael Gilligan]

On Michael Gilligan Said:

For any insomniacs, here’s some free entertainment:

For both of mine the motor needs some lubrication before use; sometimes whisky, but I find ouzo makes for a better wavy stitch pattern.  😊
The two of them predate me somewhat;
A 16K from 1925 and a K29-12 walking foot from 1914; they still work better than the current owner, and remain treadle operated.

Bill

[Michael GilliganParticipant @michaelgilligan61133]

Nice one, Bill … that’s made a good start to my day

MicaelG.

[duncan webster 1Participant @duncanwebster1]

Going back to the class 2 definition,  a UK 3 pin plug (not the new moulded type) would seem to be not compliant, because if the top comes off (I’ve seen that happen, not in my house) the connectors are exposed. Does that mean any appliance with on of these plugs will fail PAT test?

[Martin of WickParticipant @martinofwick]

Surely that would be regarded as a mechanical failure not an electrical issue per se? If your plug is broken/damaged/cracked or distorted or the pins are mot sized correctly it will fail the PAT.

It would be an unusually Darwinian household that would not replace a plug with the back falling off.

You can point to all sorts of other wiring/devices that do have exposed or quasi exposed connectors – kettle bases computer/psu leads etc.

[Michael Gilligan]

On Michael Gilligan Said:

On SillyOldDuffer Said:

[…] I’ve failed to identify George’s machine.   A careless search for Singer 120K misled me into thinking it was a pre-war type, but George said his dated from the 1960s.   Now I think the Model number is misremembered, making it very difficult to comment!   […]

For any insomniacs, here’s some free entertainment:

https://archive.org/details/manuals_singer

… by no means exhaustive, but a good start.

MichaelG.

Good find. Thanks for that Michael, I have downloaded the manual for the Singer 99K, an example of which I was given recently. It solves the mystery of how you controlled the motor – a knee operated control it would seem. Maybe I should fit one to my lathe…

[Michael GilliganParticipant @michaelgilligan61133]

In case anyone is interested [in these heady days of BLDC motors:

This is printed on the black Bakelite [?] cover of a recently acquired motor … text starts  approximately 2” from a steel mounting plate … through the slots in which the motor windings can be seen, and could be prodded with a screwdriver.

Ho-Hum

MichaelG.

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