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Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details. |
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28th Apr 2017, 9:22 am | #21 |
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Re: Industrial singer sewing machine problem.
Well, it's 1960, so it would have been difficult and expensive to do the job with transistors.
Although a nice feature for machinists in a factory production environment, you don"t really need it for amateur use, when you often do want to stop with the needle down. Interesting restoration project though. |
28th Apr 2017, 9:50 am | #22 |
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Re: Industrial singer sewing machine problem.
The motor has a slip ring with a gap in it, which obviously serves to stop it in the needle up position.
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28th Apr 2017, 12:05 pm | #23 |
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Re: Industrial singer sewing machine problem.
The valves were RCA thyratrons.
The circuit details make for interesting reading and the above number on the thumbnail circuit drawing will link to the full patent. The clutch is mechanical so no problem there, but I would like to get the brake working, as the motor runs on for around two minutes after switch off. If clutch pedal is pressed during that switch off time then the needle will operate, which could be a hazard. Mike. |
28th Apr 2017, 12:17 pm | #24 |
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Re: Industrial singer sewing machine problem.
Fit a make contact to the pedal/clutch/linkage to energise the magnetic brake when the pedal is released?
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28th Apr 2017, 1:58 pm | #25 |
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Re: Industrial singer sewing machine problem.
Or fit a pushbutton switch somewhere to operate the brake.
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28th Apr 2017, 2:24 pm | #26 |
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Re: Industrial singer sewing machine problem.
"Fit a make contact to the pedal/clutch/linkage to energise the magnetic brake when the pedal is released? ""
Probably need to be on a timed relay then,or brake would be on when motor was switched on ? Mike. |
28th Apr 2017, 2:37 pm | #27 | |
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Re: Industrial singer sewing machine problem.
Quote:
Singers for leather work are (from what I remember ), highly specialised heavy duty machines. Many's the hour I've spent in Grand dad & Dad's shoe repair workshop watching them on the Shoe making version of this- sat on a stand as all good Singers did. |
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28th Apr 2017, 2:42 pm | #28 |
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Re: Industrial singer sewing machine problem.
When you press the pedal again the switch will break, releasing the magnetic brake.
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28th Apr 2017, 2:56 pm | #29 | |
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Re: Industrial singer sewing machine problem.
Quote:
In fact, there aren't many general purpose industrials like the 366K still in use today. Factories use a huge range of specialist machines with each machinist only responsible for a small part of the garment. |
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28th Apr 2017, 2:56 pm | #30 |
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Re: Industrial singer sewing machine problem.
That's very complicated. I have a spare Singer motor of a size for that machine and it has a simple two-way mechanical clutch / brake assembly. The motor runs constantly, if the foot pedal is released the brake is applied to the output pulley, pressed half down is free-running, and pressed fully down is full speed ahead.
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28th Apr 2017, 3:08 pm | #31 |
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Re: Industrial singer sewing machine problem.
That's how most old industrials work. The machinist doesn't vary the sewing speed as is normal with a domestic machine. They know exactly what they're doing and have made the same stitches thousands of times, and just stitch at maximum speed all the time. It's very impressive to watch an experienced machinist working like that.
I have no personal experience of working professionally with textiles but an aunt was a machinist in the 50s/60s and an uncle started off as an apprentice silk weaver at around the same time. (Both the factory and the silk mill are long gone; the uncle finished up as an HGV driver). Mike's machine may have started off in some specialist application. |
29th Apr 2017, 8:14 am | #32 |
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Re: Industrial singer sewing machine problem.
""Mike's machine may have started off in some specialist application. ""
That is most likely as there used to be a lot of clothing manufacturers in this area until it all went to the far east. There was a company in Ipswich, Phillips and Piper who employed hundreds of workers making clothing and also being near the coast, there were lots of sail makers. We were only talking yesterday to a friend, who told us that she made garments in the Clacton area, so what with my partners friend who used to make boat covers, I will probably try and get them to do the carpet binding for the car. Car trimming is a job I don't relish. Give me an electrical or mechanical problem to fix any day !! Mike. |
1st May 2017, 6:54 pm | #33 |
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Re: Industrial singer sewing machine problem.
usually that sort of machine has a 24V DC clutch to make it go and a 24V brake to make it stop, and a continuously running motor with flywheel. In those days it was the best way to get the thing to start and stop instantly. The electronics would stop the needle down in the fabric so you could sew around a corner without knotting the cotton up. At the end of the seam when you wanted to take the garment out you usually pressed a knee switch or a 'heel' button on the pedal which then lifted the needle slowly out of the garment. Later machines dispensed with the positioning motor as technology had allowed the main motor to rotate slowly to the correct position by pulsing the clutch/brake carefully.
If it's a Quick motor they usually had a nice red bakelite control panel with the gubbins in and the appropriate sockets for the accessories.
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2nd May 2017, 7:04 am | #34 |
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Re: Industrial singer sewing machine problem.
Hi Kevin, that sounds spot on. The control panel has long since parted from the machine and I suspect the motor was originally from a Pfaff sewing machine.
I have a German pal who is going to see if he can get a manual on the motor which will be handy. I have checked the terminals on the DC motor end of the main motor and one reads zero and the other three are fairly high resistance. I will hang on until I have more information. I had wondered if they had used an eddy current type of brake, but info on this motor is very thin on the ground. I now have made up a nice control box with contactor and push button start stop. When the machine arrived here, the main motor was controlled by a house lighting switch, fed by bell wire !! Mike. |
2nd May 2017, 10:29 pm | #35 |
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Re: Industrial singer sewing machine problem.
I've never seen an eddy current sewing clutch/brake head, thats not to say they dont exist. Normally just a big coil or 2 to attract the friction clutch (graphite loaded cork) to the flywheel, slipping as necessary for speed control. Some machines relied on your expert foot work, but others had a closed loop speed feedback, to compensate for different types of fabric; usually a pulse generator or mag pickup. There'll also be a slotted switch or cam to tell the control when the needle is 'up' or 'down' so it stops properly. The brake circuit usually has an overpulse to increase the actuation force and prevent delay at the point of stopping, which then decays once the thing's stopped to prevent the brake coil overheating. Industrial machines have such inertia that without a brake, you could take your foot off and it would sew another foot or so before stopping...known as 'running on'. Not good for the quality garment industry!
BTW the positioner (position sensing switch) should be on the sewing head, not on the motor. If it's on the motor, then creeping belt slippage would run it out of position very quickly, since the 2 pulley's arent mechanically locked (assuming yours is v-belt drive).
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Kevin Last edited by McMurdo; 2nd May 2017 at 10:36 pm. |
8th May 2017, 5:43 pm | #36 |
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Re: Industrial singer sewing machine problem.
I have got a stage further with the braking of the motor. I removed the fan end cowling from the motor and was surprised to find that there are a couple of pulley wheels in there at right angles to the pulley on the same end of the motor. (Main drive pulley is on the other end of the motor (Clutch end.)
The rubber belt was not in place and had been tied to one side by a previous owner. It would seem that this is part of the needle positioning device and normally would be rotating the mechanism at the clutch end, until the machine is braked to a stop, and then a 24DC volt motor comes into action to rotate the main motor shaft to the required position. Thumbnails enclosed to show the set up. These are not my machine, but gleaned off the net. It looks like I will have to remove the dc motor/and brake section to determine which set of wires serves brake or motor. Hopefully a simple job to strip.(famous last words.!!) Mike. |
12th May 2017, 4:24 pm | #37 |
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Re: Industrial singer sewing machine problem.
Stripped out the part where the electro-mag. brake is and now wired it in though the transformer that is in the motor terminal box. I have wired it so that when the push button stop is pushed the brake should come on as well, through another set of contacts. (Telemechanique switches).
However..... no joy on the mag brake. When it is switched in it pulls the DC volts down severely, so not sure at this moment where to go now !! Thumbnails below.The small rotator has cork linings on both side and is splined to fit the shaft in the housing. Mike. |