Saturday, December 31, 2011

How to Re-wire a Potted Motor, Part 20: Hooking It All Back Up

Now we’re at the final step to getting your machine back up and running!

Start by sliding your newly-renovated motor onto the shaft.

Tighten the two motor mounting screws securely.

Then, unscrew the terminal body. Note that I’ve tucked the two motor leads behind the terminal mounting bracket. This is so that we can determine the proper length to cut the tails.

Now we’re going to make new connections on the ends of the wires. As we went over in Part 4, you can either make your own eyelet and solder it, or use crimp-on connectors.

Option 1: Self-Made Eyelets

The self-made-eyelet-and-soldering route requires plenty of wire, which is why we’ve left the “tails” of the motor leads so long. You’ll need to calculate where to cut the wire such that you’ll have plenty of material to form your ring. I suggest measuring and practicing on a scrap piece of wire first, so you can be certain where to cut and strip in order to produce a ring that will still reach the post it needs to connect to in the terminal body. If in doubt, cut too long, not too short!

Option 2: Crimp-On Connectors

Here I’m going to do crimp-on connectors, which requires less length and is easier for me to execute. I generally determine where to cut by letting the terminal body hang naturally, supported by the lighting wires that are still connected, and then drawing the motor lead over the knob that it will fit under. I then pinch the wire to the side of the knob furthest from the motor, as shown in the photo, and cut there. This will make the final wire long enough that I can comfortably manipulate it into place.

Next I strip the wire ends to the length required for a crimp-on connector, just 1/4" or so.

Then I gather the connectors and, very important, I immediately cut two pieces of 1/8” heat shrink tubing about 1/2" long.

I slide the heat shrink tubing onto the wires first…

…and only then do I attach the connectors and crimp them on.

Then I slide the heat shrink tubing down into place, as seen below. You’ll notice that now I’ve pulled the motor leads OVER the terminal mounting bracket.

I’ve done that so that I can get the wiring a good distance away from everything else, to comfortably fit a lighter under the heat shrink tubing.

Now they’re heat-shrunk and ready to go.

Re-Attaching the Wiring
When the ring connectors are ready, tuck the wiring back UNDER the mounting bracket, in their final position. Pull the red and black wires over to their appropriate posts on the terminal. (Here I’m working on a 201-2, which has a light switch, and you’ll observe I’ve had to thread the black wire underneath a different wire that arches over it, connecting the light switch to the red post.) If you have a cabinet-mounted machine, connect the foot controller wires too, even if the machine isn’t in the cabinet yet. We need to do some testing.

After connecting the right wires to the right posts, we tighten up the thumb screws. Get all three of them as absolutely tight as you can with your fingers.

Now it looks like this. Be sure you’ve got the motor leads tucked BEHIND the bracket…

…then screw the terminal back into the machine. Do NOT overtighten this screw. The terminal body is made of plastic and easy to break. You only want to get it tight enough that it doesn’t wiggle around when you plug the cord into it.

I’ve grossly overexposed the next shot so you can see how the motor leads come down unobtrusively from the motor and disappear behind the mounting bracket.

Now we’re at the moment of truth!

Running the Motor

I plug the machine back in without re-attaching the handwheel, because I want to run the motor with no load--that is to say, not powering the rest of the machine--to ensure that it runs smoothly. This way if the motor doesn’t run, I know it can only be the motor that is the problem, and not some jam somewhere else in the machine.

Then I get the button controller up on the table. (And obviously, you should not stick your fingers inside the motor housing for any reason!)

Here are the results:

That’s the sound of a potted motor 201 running with no load. Sounds very different than when it’s connected to the rest of the machine, no? Sort of reminds me of a jet engine. I’ll continue running it for a few moments to ensure it runs consistently. And if you’ve inserted new brushes, you ought to run the motor for five minutes or so anyway, to wear the brushes in.

Warning #1: If you run the motor as I’ve done in the video above but it sounds different--for example, if it buzzes first and starts haltingly--STOP and unplug the motor immediately.

Warning #2: If you run the motor for a few minutes and it gets warm, that’s fine, particularly if you’ve been running it full tilt. But if it gets HOT, please STOP and unplug the motor immediately.

Both of those warnings are signs that something is wrong with your motor, either in the field core, the windings or the armature itself. And that something might be dangerous, which is why we ought to unplug the machine immediately. Sadly, those problems are currently beyond the scope of this blog.

But hopefully, everthing has turned out fine.

Re-attaching the Handwheel

It’s my habit to unplug the motor when I re-attach the handwheel, though strictly speaking it’s probably not necessary.

The next thing I do is use the grease syringe to dab some droplets of grease around the perimeter of the fiber gear. People often over-grease these things, but you really don’t need to go nuts with it.

Then I put a single drop of oil on the shaft.

Next I slide the handwheel on.

Replace the washer.

Then screw the stop-motion wheel in, all the way.

Don’t forget to tighten the set screw.

That’s it! Congratulations and enjoy your machine!

Back in business.


  1. Thank you so very much for this very interesting and complete series. It will be of much help to us. Have a Great New Year.

  2. Phenomenal series, Rain. Happy New Year!

  3. Thanks to you, Rain, I now have a 201 that runs. I wish I had a CLEAN 201 to go with my wonderful refurbished motor.

  4. I have been fascinated by this series! I only wish I had the guts to do this to my 191J's motor. How can I tell if it even needs to be rejuvenated like this?

  5. 2 thumbs up (way up), 5 stars, and a perfect 10!!! By the numbers, Rain ROCKS!!! You are a great teacher, thank you for taking the time to do this.
    Diana in CNY

  6. Wonderful!! Thanks for such a great series.

  7. This is the best tutorial I have ever seen. Yvonne

  8. You are a great teacher! Now, I've got to find a machine to practice ;) . Happy New Year!

  9. Rain, this whole tutorial is great! Thank you!
    You mentioned possible problems with the windings; could you elaborate on what those problems might be, and how they might be identified? Would it be something one could spot visually?
    I enjoy learning about the motors; you have made the process much more clear.

  10. Simply, simply an awesome series, Rain! Kudos for all the work you put into this series. Question now is: What will your next series be and how in the world can you top this? :) -Shari

  11. What a lesson!!! The Internet made it possible for the wonderfully knowledgeable, generous experts like you to share their experience with others. I had great joy reading it, although I am not ready for the job. Thank you, thank you. You are a great guy from NYC.

  12. I am somewhat of a tinkerer and owner of an old Singer 201. I have been afraid to tackle some of the things you show, but the sections are so clearly decribed AND pictured, that I plan to disassemble all necessary parts to clean and lubricate my machine. Superb job!!

    John W

  13. thanks for the wonderful tutoral. Language and pictures were perfect for inexperienced me. My machine is back together and it RUNS beautifully.I can't belive I did it!thanks to you!!!!!
    Judy in Ohio with a beautiful 15-91


    First of all, I am very grateful for this tutorial - utterly fantastic pictures of the step by step process. THANK YOU! :) "If" I can pull this off, it will save me a lot of money re-wiring my 1939 Singer 201-2. It's a beautiful machine well worth the trouble. BUT...and this is where the "if" comes in...I CANNOT budge one of the screws holding the motor housing to the machine, the two big screws behind the handwheel that you said are "tight". OMG, not even "tight", how about never, ever coming out of there! :( I managed to get one of them out by standing over the machine and leaning into the screwdriver as I turned. The other one isn't coming out of there and I'm afraid I am stripping the groove by my repeated efforts. If I can't get the motor housing off the machine, I can't re-wire it. If I can't re-wire it, the machine can't be used (wires are completely stripped down to bare wire). HELP!

    1. 1) Put a few drops of oil around the screw head and let it penetrate overnight.

      2) Use the proper-sized bit, like a Brownells 360-6.

      3) Use a long driver.

      4) Be sure you are driving hard, and perfectly perpendicular, into the screw head as you begin to twist the driver.

      - Rain

  15. I'm going to go get the screwdriver you mention and try again. I already oiled it and let it sit over night, and I do have a long driver, but maybe not the right one. Is there a back up plan in case I can't get it off???

    1. 1) What is your name? I don't like having conversations where the other person doesn't bother to attach their name.

      2) What size/type screwdriver bit were you using when you initially tried to remove the screw?

      3) Is the problematic screw head already stripped?

      - Rain

  16. MKB stands for Mary (K.B.) :) Thanks for your help!

    SO...I took the whole thing to Home Depot and they got the screw off with a power driver that was long enough to reach in there. But even they couldn't get one of the feed dog screws off (a whole other story - which may be moot at this point!)

    I followed your directions the best I could with the exception that I did NOT remove the worm gear (is that the right term?) from the motor housing. I knew I could never get those screws out and I didn't want to strip them down trying so I just left it in and carefully worked around it. My wires themselves were in good condition, only the insulation had all crumbled away so I put the tubular shrink coating all the way up to where the wires disappeared into the Wherever That Is(?) (I'm sorry, it has been a LONG day, and I am kind of frazzled!) I marked the red and black wires as you indicated and tied them together exactly as you showed. Put everything back together, hooked it up, plugged it in and then...nothing. Tried using my FW double lead power/controller to see if it was the controller at fault. Nothing. When I switched the contacts around just in case I had them backwards, I tripped a circuit breaker and that's about all the action I got. Note: machine worked fine before I started this project! Note also that I have replaced controllers and light fixtures in the past and never had a problem hooking them up correctly in the terminal. Did I ruin this motor by not removing the gear when working on my wires???? :(

    1. Hi Mary, if you did not remove the worm gear and armature, I assume that means you did not crack open the field core?

      - Rain

  17. Hi Rain, okay, if by that you mean did I separate those two halves (insert the screwdriver against the rubber and gently pry them apart, etc.) then yes, I did that. I just didn't remove the gear, it remained in place. I took a few photos while I was in there, but don't know if I can attach them here to show you what I did. Thanks, Mary

    1. Hi Mary, I'm not sure what you've done; but obviously if you didn't remove the armature, you didn't clean the commutator, which is one potential problem.

      Another potential problem: You wrote "My wires themselves were in good condition, only the insulation had all crumbled away"--if the insulation had crumbled away, that means the wires were *not* in good condition. The metal wiring itself can become brittle over time.

      You also wrote "I put the tubular shrink coating all the way up to where the wires disappeared into the Wherever That Is(?)" If you had correctly separated the field core, you would be able to see exactly where those wires terminate, which is in the windings as opposed to "Wherever That Is(?)"

      Think of it this way--if you wrote me out a specific step-by-step recipe to bake a pie, but then I only followed some of your instructions and skipped others, and then the pie didn't turn out right, what could you tell me? The bottom line: It's impossible for me to figure out what the problem is, because I do not understand exactly what you've done!

      - Rain

    2. P.S. Are you in the NYC area, can you drop your machine off in downtown Manhattan so I can take a look?

      - R

  18. The "Wherever That Is" is the snakey looking thing wrapped in black tape, where the wires come out. Sorry I don't know the names of these parts! The electrician at Home Depot looked at my wires when I carried it in to buy the parts I needed and told me they were in very good condition, nothing frayed or brittle, so I went with that. (Sounded good to me, whose motto when working with these machines is First Do No Harm or Leave Well Enough Alone!)

    But the conclusion to the story is this: I crimped a new lead onto one of the wires...guess I didn't crimp it on there tight enough the first go-round with my weak grip. Hooked it up again and it RUNS!!!

    Rain, I appreciate your tutorials and all the time you took to put it on your blog and answer questions. That is very generous of you and I am sure there are many of us who are grateful to have found this information. :) Mary

    1. Mary, I'm just glad you got it running! One less machine in the garbage, one less machine you had to buy. Congrats to you for sticking it out!

      - Rain

  19. Rain, Thanks so much for all the personalized help; it certainly felt aimed at my level.

    I doubted my self on the soldering (after all the stumbling blocks with SCREWS). Those wires were definitely in need of a fix. I did it and it was a breeze. (Couldn't do anything right with the old wire I used for practice!)

    My old brushes had a step worn at the bottom edge (bottom of commutator, you could say), about 1/16th. when I put in the new ones, I could look into the hole and see only shiny copper. I feel like I'm good to sew, but cannot imagine how this step could have formed. Any ideas?

    Karen in Houston
    Happy to be part of such a generous community

  20. Rain...
    You rock dude!!
    I'm the recent owner of a 1938 201-2, and am looking forward to some in-depth tune-up. Your great tutorials are going to be a huge part of that.

  21. Oh Mighty Rain! I salute your wise and good counsel. My 201-2 purrrrs like a kitty. It took me a bit over and week to tear it down and put it back together, most of that time spent sitting in a terrified ball getting up the nerve to either open some portal to destruction or wiring it up so it would fly into the ceiling when I plugged it in.
    Thank you so much! Actually, if my mom could, she'd thank you, too.

  22. Rain....What a load of rubbish this blog is!
    Just thought That I would try and give you a change, from everyone saying what a "Guy" you are!
    Unfortunately, I can't do that, because.... "You are the man"
    Thank you so much for doing what you have, I followed your every instruction, and I've done it! From start to finish.
    Brilliant, Brilliant, Brilliant.
    Thank you. ("WHAT A GUY")
    Andy, England. By the way, can you come and check that I've done it right?

  23. I am working on a fashion mate 223 and had to replace the vertical top gear (normal for this machine) and started looking at the motor to make sure it was ok. I went through it and cleaned it up and put everything back together, plug it in and nothing ! I took the motor apart again and found the wires leading up to where the brushes contact were broken. I could not believe that 9(!)out of 11 are broken. Is it possible to solder them back on or should I just get another armature or motor ? Great site by the way, I love seeing those early machines.
    I appreciate any input,thanks.

  24. Love the detail. I learned more than to refurbish a motor. I learned soldering, heatsinking, etc. Thanks much!

  25. I have to add my thanks to the list of others for your amazing tutorial. I have a 15-91 and a FeatherWeight that I will begin working on and plan to use this tutorial as my guide. I also was wondering if there is a way to send monetary contributions directly to you for all the help you have given. If there is a link for contributions and I missed it, perhaps you could direct me to it...Thanks You Rain, Rob.

  26. Rain,
    Thank you so much for this blog! I have just rebuilt a motor on a 15-91 centennial edition motor (which, by the way, was a worst-case scenario- grease everywhere in the motor & no insulation left on the wires) and it runs beautifully! I would not have had the confidence without your instructions. Thanks again!

  27. This site is amazing! I am hoping to save a 1949 15-91. It was running fine but the wiring was really dangerously degraded, so I leapt into this. I got all the way to this step and plugged her in and... nothing. No motion, no heat, nothing. Not sure what to check next. What a bummer.

    Cheers, Kate

  28. Like others I must thank you! What a great effort of generosity! And my mother (85 yrs. old) can't wait to get her hands on the 15-91, which I've finally found after searching for quite some time. Thanks again!! Now I'm about to go to work on the 201.

  29. Another perfect tutorial to add to your list of perfect tutorials. This is definitely the way to do things. Thanks Rain