Grounding Vintage Sewing Machines
#31
I apologise for coming across as rude and of course you're right about why 240V was chosen in Europe/Australia. Incidentally transmission lines carry anything up at to 500,000V (that's why they buzz).
About the 32VDC woman: Speculation as to what would have prevented her death is pointless, as the facts are not known. The higher current probably burned out the wiring much earlier than it should have, modern trip switches would also prevent such accidents too.
My 222k requires 1A at 32VDC, but the 240V version needs 130mA. The replacement motor will last 50 years even without earthing as a result and is unlikely to ever endanger anyone.
It's ironic you described safety standards as "overkill"
My 319 was earthed from new (1956). Earth wire was connected to the top of the motor connector and on the machine-mounted bakelite connector block was a copper contact connected to the machine, so there is a precedent and it was implemented by Singer (possibly as a result of that article, but I'm only speculating).
About the 32VDC woman: Speculation as to what would have prevented her death is pointless, as the facts are not known. The higher current probably burned out the wiring much earlier than it should have, modern trip switches would also prevent such accidents too.
My 222k requires 1A at 32VDC, but the 240V version needs 130mA. The replacement motor will last 50 years even without earthing as a result and is unlikely to ever endanger anyone.
It's ironic you described safety standards as "overkill"
My 319 was earthed from new (1956). Earth wire was connected to the top of the motor connector and on the machine-mounted bakelite connector block was a copper contact connected to the machine, so there is a precedent and it was implemented by Singer (possibly as a result of that article, but I'm only speculating).
#32
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Location: NY, USA. Originally Birmingham, UK
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Overkill
I admit the irony of that escaped me the first time around!
Manicmike, I reread my post and realize that the wording was misleading. I wasn't actually referring to you when I mentioned rudeness.
I imagine the Singer grounding thing and the current standards simply happened as a natural evolution of design. Very early appliances had chassis components that could become live depending on which way around you plugged in the non-polarized plug!
Unfortunately, evolution of design has also brought us to 'value engineering', and while todays machines are electrically safer, they also have plastic gears and built-in obsolescence.
I want the best of both worlds, which is why I want old mechanics and modern electrics.
I admit the irony of that escaped me the first time around!
Manicmike, I reread my post and realize that the wording was misleading. I wasn't actually referring to you when I mentioned rudeness.
I imagine the Singer grounding thing and the current standards simply happened as a natural evolution of design. Very early appliances had chassis components that could become live depending on which way around you plugged in the non-polarized plug!
Unfortunately, evolution of design has also brought us to 'value engineering', and while todays machines are electrically safer, they also have plastic gears and built-in obsolescence.
I want the best of both worlds, which is why I want old mechanics and modern electrics.
#33
Super Member
Join Date: Aug 2013
Location: Springfield Oregon
Posts: 1,481
Anyone ever disassemble their toaster oven? Notice the lack of a ground wire, and they catch fire easily because of the buildup of grease, crumbs, etc. Probably one of the chief reasons for GFCI requirement on kitchen counters. Google me on this, but GFCI outlet will protect you on your devices even if not grounded, because it's looking for an imbalance between the two legs and will trip within milliseconds if you become the return path to ground. I use one on my test rig for rewiring sm motors and controls and lights. As well as a variac. Having a barefoot on a hot FC won't give you more than a tingle, unless you happen to also provide a ground return, like a floor register with metal ducting. Just my 2C worth.
#35
Absolutely right Tammi. When my nephew was about 3 he was an inquisitive child. I was soldering something and he kept going to touch the iron. I warned him at least three times not to go near it and told him it would really hurt. Of course when I briefly left the room the inevitable happened. He screamed in pain, we ran his hand under the cold water and learned a valuable lesson. He's just turned 30.
No, it was probably me.
#36
Never would have guessed that!
Now if you'll excuse me, I have to go win something
#37
Good luck! She'll love you for it!
#38
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Join Date: Jun 2014
Location: NY, USA. Originally Birmingham, UK
Posts: 85
Not you either.
I'm not offended by lively discussion, just the direct insults.
I did a search and found quite a few posts about people getting mild electric shocks (often described as a 'tingle') from their machines. That seems like a valid enough reason to add a ground.
This kind of risk could almost be eliminated by a periodic visual inspection of the wiring, but there are some wires on my machine (for the light) that can't be visually inspected without removing them from the machine.
They are routed through the casing, and there are large sections which can't be seen with the wires in situ.
I'm not offended by lively discussion, just the direct insults.
I did a search and found quite a few posts about people getting mild electric shocks (often described as a 'tingle') from their machines. That seems like a valid enough reason to add a ground.
This kind of risk could almost be eliminated by a periodic visual inspection of the wiring, but there are some wires on my machine (for the light) that can't be visually inspected without removing them from the machine.
They are routed through the casing, and there are large sections which can't be seen with the wires in situ.
#39
#40
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Join Date: May 2013
Posts: 670
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