Sir marcolo . . . . .
I don't see that connector using standard IEC wiring color codes . . . . . but seeing that the WHITE connector that goes into the machine proper would have its two outer fingers being connected across a series field and armature of an AC/DC brushed drive motor, leaving the center connector for the powering of a mounted sewing work light .
Of the two external large GRAY covered AC power wires, we need to know which one goes to the AC power and which one just loops up and goes into the foot control. Unless being corrrected, I am seeing the upper wire doing a single half looping up and going into the controller.
I am seeing the large BLACK "321" item as being a power resistor that has its start connections BROWN wire and then a BROWN wire tap off at each of 5 identical values of resistance wire windings, and then one more like resistance winding at the very ends last BROWN wire.
That power resistors BROWN wires ends are then transposed in the same order, to the stacked leaf contacts of the speed controller switch.
Now, if the mustard colored capacitor only has the TWO leads coming out of it on one end and going to the dual wound, iron cored " I " inductor, I see this L-C combination and the separate greenish colored 0.05 cap as being associated with supressing EMI / RFI back into the AC power line and additionally providing some abatement of arcing at the universal motors brushes to commutator segments.
As for its electro-mechanical action, the unit is being inactive until the black plastic / bakelite insulated pressure foot tab is pressed down enough until the first leaf contact connects with its adjacent contact. Then that has all of the series resistors running the motor at its slowest speed. Then, with additional foot pressure, each additional leaf contact shorts out and drops its resistance, to then have the speed incrementally stepped up faster at each leaf switch closure.
At max foot pressure you will then have them all shorted out and the machines motor running at its full speed, until any foot pressure decline.
HOWDOIDOITTOIT ?
We e e e l l l l l l. . . . first you take ohnmmeter in hand and place to its lowest ohms range and IF you are unable to interpret my prior explanation directly to the RED-BLACK and GRAY wires coming out of the speed controller and then their reterminating into the WHITE sewing machines associated connector .
Then go to the WHITE sewing machines 3 pin connector and its exposed wires coming into it from the controller and sequentially try each of the RED to BLACK . . . . RED to GRAY . . . .BLACK to GRAY wiring possibilities, while you start pressing on the pressure foot tab.
Expect declining resistances and then a final short from the ohmmeters readings . . . . on the CORRECT one of the above combinations of wirings...
If not, you must have a resistor or connection problem.
Get back with your findings and we will sort out problems /versus / possibilities.
Thaaaaaasssssit . . . . .
73's de Edd . . . . . . . .
As a kid, I was so ugly that my father just carried around the picture of the wife and kid models that came in his wallet.
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I'm trying to repair a variator from a 60s sewing machine meant to control the motor speed. The motor does not turn anymore and since the variator had just been dropped before the fault occurred I suppose it is the problem. There are only a few components: 2 capacitors, 1 coil, a "variator assembly" with a series of contacts (which seem to work fine) driven by a pedal which I removed, and one large cylindrical component which may also be a capacitor (only labelled 170-250V), see picture. The plug which feeds the sewing machine has 2 cords: the upper one is mains power, the lower one goes to the variator. How can I identify what's wrong? Thanks a lot for your help.
