Saturday, April 25, 2015

Rewire Willcox and Gibbs Motor - Part 1

This tutorial is a step by step photo documentation of rewiring the motor on a vintage (1937) Willcox and Gibbs chain stitch sewing machine motor.

List of Materials:
  • Wire:  18/2 SJOOW Black 300V Priority Wire --- Link To Source
    20 feet will do the motor and the foot controller
  • Round Vintage Antique Style BLACK Electrical Plug --- Link to Source
    2 each will do the motor and the foot controller
  • Item Number 8767K226
    Felt Cord, White (F1), 3/16" Diameter, 5' Length --- (grease tube wick)
    Link To Source --- Type the item number into the site search field
  • Item Number 69765K411
    Single-Conductor Fixture Wire (TFFN), 18 AWG, .085" OD, 600 VAC, Black --- (motor wire)
    Link To Source --- Type the item number into the site search field

The wire is the closest match to the wire that came on my machine.  I've seen some with the braided cloth wire.  The source for the plugs above also carries the braided wire.

Procedure:



Lay a towel down and lay the machine on its back, then remove the screw directly under the motor. The motor will not come off the base until you remove the sewing machine.


To remove the sewing machine, unscrew the large wingnut.  I had to squirt some AeroKroil into the threads of the wingnut and then lightly tap on the arms of the wingnut with a small hammer to get it to loosen.


Once the sewing machine is free, the motor will be free of the base.  The motor will still be attached to the base by the electrical wire connection.  Don't lose the two felt drive pieces between the motor and the pulley.  It looks like someone had been into the connection bay before.  The original owner may have added the motor base at some point.  At any rate, the connection was loose at the wire nut.


The wire passes through a bakelite grommet in the base.  The grommet unscrews for cleaning.


Cut five feet of wire (original length) or whatever length works for your situation.

The wire comes with printing along its length which identifies its construction.  This does not match the original look.  The printing can be removed easily with Goo Gone.


Use a vinyl or rubber conditioner after to keep the sheathing material from drying out.


Remove about four inches of the sheathing.  Cut down the length of the wire from the end.  Cut only deep enough to put a slice in the rubber; not all the way  through.


The sheathing will break apart as you pull it open.  This will keep you from cutting into the insulation on the inner wires.  Cut away the outer sheathing as well as the paper; leaving only the two conductors.


Pass the wire through the bakelite grommet and into the electrical connection bay.


Tie an Underwriter's knot in the wire to act as a strain relief.


Adjust the knot tight against the black insulation.


Now it is time to install the new plug on the other end of the wire.  Prepare the wire in the same way as on the other end.  Tie an Underwriters knot in the wire conductors and wrap about 8-10 turns of electrical tape under the knot.


Slide the base of the plug up the wire to test the fit.  What you want is the tape to fit snug into the tubular part of the plug and the knot sits at the bottom of the dome shaped base.  You may need to add or remove some tape to achieve the snug fit.


Strip the wires leaving about 1/2 inch of insulation above the knot and twist the wires.


Wrap the wire clockwise about the screw at each terminal so that the insulation is tight up against the head of the screw and tighten.  Slide the two parts of the plug together and install and tighten the outer screws.


The base is now complete and ready for to receive the motor.


Note the electrical tape where the wire passes into the motor housing.  I removed it and there was Scotch tape under that.  Someone has attempted to fix the wiring before... never a good thing.  We'll come back to the wiring later.


First, remove the grease tubes with a flat screwdriver which will expose the springs and wicks. Unscrew the wicks from the springs, discard the wicks, and put aside while we complete the wiring.


Remove the two plastic thumb caps nuts from either side of the motor shaft being careful not to lose the springs and brushes.

Note which hole each brush came from.  It is better if they go back where they came from.  If you get them mixed up, it isn't the end of the world.

Clean the springs and brushes with a toothbrush and some alcohol and set a side for later.  These brushes are still long enough to reuse.


This repair is going to be easier than most.  We don't even have to open the case of the motor.


Inspect the wire all the way to the armature.  In this case the wire is in good condition.


Remove the insulation about 1/4 inch from the motor housing or from where the insulation has failed to the end of the wire.


Using a pair of pliers to keep any strain off the wire where it connects to the armature, twist the exposed wire to the end.



From the end of the insulation, measure 3/4 inch, mark and cut the wire.


Continued in the following link:


Hope this helps,
Michael

Disclaimer:
Don't attempt the techniques explained in this article if you don't have electrical experience or are not certified in electronics.  Doing so may result in electrical shock and/or death.  If you decide to act on these techniques, you are doing so at your own risk.  It is recommended to have your work checked by a licensed electrician or certified electronics expert.

2 comments:

  1. Thanks for this great post! I have an old W&G motor I need to rewire, but it looks to be in worse shape than this one. I think the wiring from the brushings also needs to be replaced. Do you have any photos of how to do that? Can I send you some photos and see what you think?

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    Replies
    1. I haven't looked into rewiring the bushings. I'd be glad to look at your photos.

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