When the machine arrived, both the motor wires and the light wires were disconnected from the terminal. Since the insulation on the motor wires were okay, I figured I'd need the motor before the light. The other thing I would need was a foot control since there wasn't one. After rounding up a pedal, I sat down to figure out which wire went where. It looked simple enough since I've had experience with the same sort of three post terminal on many of the vintage Singer machines.
Note the wire terminal here
mounted on a bracket and connected to the motor bracket bolt.
Although schematics and wiring diagrams appear a tad complex, the wires for an older sewing machine such as this Pfaff have become rather simple to me. The light on this machine, and many others, is a two wire affair. One single strand of wire brings electricity to the light, the other carries it away, or at least that's how I look at it.
Sometimes the light has it's own switch built in, other times the switch is located elsewhere. The switch is an interrupt for the current: throw it this way and the current is allowed to travel to the light bulb, throw it the other way and current isn't allowed to travel to the bulb.
If you can imagine that, then essentially the foot pedal (or knee control) is nearly the same as the light switch diagram. When there is no pressure on the foot pedal, current is not allowed to flow - the switch is closed. When there is pressure, current is allowed to flow and the switch is open.
The difference between the light switch and the foot pedal to me... is like the same as a house light switch or a house light dimmer. The simple switch is either on or off while a dimmer controls the amount of power to the light. In theory then, the foot control behaves like a light dimmer (or rheostat) in the room of a house. The word rheostat is used for both mechanisms.
So power goes along one strand of wire into the foot pedal... then it comes out the other strand of wire (if the pedal is depressed) and this one strand then goes to the motor. Power then exits the motor on the last single strand of wire on it's circuit and goes back to the electric plug: electric in, and electric back out. Makes some kind of sense to me.
In many ways the circuit for the light with a switch is the same circuit for a motor with a pedal. What the common vintage sewing machine electric terminal does... is allow for these two individual circuits to get power from one source: the cord with the plug that goes into the wall socket. So the terminal acts as a place to connect two separate routes.
Where it becomes complex in my head... is the number of wires involved. There are only the normal pair of wires that come from the wall plug, and they enter the terminal box where they are then split into two. With the motor circuit, the 'power in' line has to travel through one side of the pedal, out the other side, and then to the motor, through the motor, and then back out and to the 'power out' line of the terminal that will return to the wall socket on its one strand, just as it came in on the other.
This is probably an over-simplification on my part, but it works for me. Ask me how to wire a light switch at this end of the hallway, and then that end, for the same light bulb in the middle... and I'll have no idea. Even as I sit here and type this, the sewing machine sounds simple enough: two wires. One carries power in, the other carries it out. Everything you need to have power to must lay in between, and have a line in, and a line out. If it were that simple then why are there six wires to a sewing machine and three plugs on the terminal?
Oh my. The easy circuit to explain are the two wires for the light. Power-in goes to the light along one wire and power-out comes back. Often, there's a switch along the power-in line. That's it.I can therefore eliminate two of the six wires in my head. I know what they do.
The foot (or knee) control is what adds all the complexity. The reason it's a little confusing is because the control is way over there... and the motor and power source- are way over here. The third post on many of the vintage sewing machine terminals is simply a place for a splice in the wire. That's all it does. The third post connects the one single wire that is carrying the power away from the pedal... to the single wire that will now take the power and send it to the motor.
It's this way on the old Singer three wire terminals, and after examining the three post connector that was on the Pfaff, the theory appeared identical. Here's the Singer above. The thing to note on the Singer is that the splice is on the middle post. The middle post connects the one wire that is coming from the pedal and going to the motor.
Yes, I know. This might be boring.
Many people would rather not learn anything new and just hand it over to a trained professional. I wish I had the luxury, but I do not. If it needs fixed, I have to learn how to fix it, and there is a reason why I'm mentioning all this.
On all of the old Singer three post terminals the terminal for the pedal-out wire to connect with the motor-in wire is the middle post. This is not the case with the terminal that came with the Pfaff. By all appearances the terminal box on the Pfaff seems authentic and original to the machine, but the order of the wires is NOT the same as the Singer.
Needless to say, I had it wired wrong the first time and blew a fuse.
The wires above are in the correct order, but I'm not finished with them yet.
(Also, minus the light wires)
(Also, minus the light wires)
This made me step back and carefully examine the Pfaff plug. I got out a magnifying glass and it didn't take long for me to correctly locate the pedal/motor splice post and now, I feel a need to show everyone what I learned since mistakes can be learning tools. Oddly, I searched and searched and couldn't find a single reference online to how to wire this terminal. So maybe we're breaking new ground here.
The splice post for the pedal wire -power out- to connect to the motor wire -power in- is the post marked #3.
Anyways. after figuring out which wire went where I tested out the motor. This too is an interesting dilemma. Pfaff's are known for their tight tolerances when it comes to manufacturing. The problem with tight tolerances is that since there is even less space between metal surfaces than other machines... they usually need oiling a little more frequently.
If they are not oiled more frequently, or not at all for awhile then -as with many older machines- oxidation and rust can begin and the machine may begin to tighten up. The original Pfaff 130 had two things going for it: the first was a detailed oiling procedure, and the second was a very beefy 1.5 amp motor. An extra beefy motor will spin a machine that may have one little spot that's still not letting the oil soak in as far it should. Sometimes allowing the machine to spin will actually assist the oils ability to seep into that spot.
I had the Pfaff mechanisms spinning fairly free by hand when I wired the motor and pedal and decided to give it a try. The hand wheel would not take off running no matter how hard I pressed on the pedal. I still had to nudge it to go. The machine did spin and it spun well, but the original 1.5 amp motor had been replaced with a 1.0 amp unit, and I could tell. I have since taken this motor apart, checked the brushes, cleaned and serviced the motor to the best of my ability... and it still has trouble turning a slightly sticky Pfaff. It will do for now... but either the machine still needs to loosen up a little more or perhaps a different motor should be considered.
All that being said, the machine really does shows signs of life. I feel right now that there's a couple of spots that are a little thirstier than others when it comes to machine oil... and hopefully that will be rectified soon. It could probably sew right now if I asked it to... but I don't really think it's ready yet. When I finally get that one little rough spot out of the rotation (oddly right at the very tippy top of the thread take-up lever movement) then I'll be far more certain that the machine is ready to take the next step.
Until then...