Page last modified: 02/27/14
The Stator Papers VI
How to rewind your own stator
By Gene & Kim Maynard
(With author permission, originally from http://www.suzukicavalcade.com)
NOTE!!! See comment at the end of the article before attempting this project
PINPOINTING THE PROBLEM
Step 1: Battery Check. Before performing any test on the charging system, be sure battery is in good condition and fully charged. Any automotive store can do a load test for you at no cost.
Step 2: Start the engine and set lights to bright. Using a multimeter, check across the battery terminals. At 1,000 RPM you should read 13+ DC voltage. This voltage should increase as engine RPM increases. At 5,000 RPM voltage should be between 14v and 15v DC. (Note: The regulator-rectifier can lose 1 of its 3 SCR diodes and still show an increase in voltage as engine RPM increases. This voltage will be in the range of 11.1 to 12.7 DC. Don't let this fool you into thinking your voltmeter is incorrect. If this happens the regulator-rectifier is most likely bad and should be replaced.)
Step 3: Do the "no load" generator test. Disconnect the generator from the regulator. This will be the three yellow connections at the regulator-rectifier. Start the engine and connect multimeter to any two of the three yellow generator wires. (Be sure to set multimeter to AC before performing this test!) Since this will be AC voltage the polarity doesn't matter. At 5,000 RPM you should get 90 volts AC or higher.
DO IT YOURSELF STATOR REWIND
Before you start, make sure you have these things on hand:
* 2-lbs high temperature 17 gauge (18 gauge will work) magnet wire. If you can't find this wire locally, you can call Allied Electronics at 1-800-433-5700. Locally the wire should cost around $5.00 per lb plus a $5.00 spool charge.
2-lb should cost about $15.00.
* You will also need some epoxy that will withstand heat and oil and will stick to the coating of the magnet wire. I used EpoxyLite Insul Spray 7001. Two other brands which are also good are 3M 2116 and 3M 1838.
* The tools you will need after stator has been removed from engine are:
black permanent marker
Step 1: Remove the factory clamp holding the wires to stator. Cut the three yellow wires as close to the original connections as possible. Remove the cloth insulation. Save these so you can use them later. With a sharp tool or a scribe, make a mark below the core where the wires enter the winding (figure 1). This will be your start point for wire #1 later. At this point, it would also be a good idea to sit back and get a good mental picture of each side of the stator, making notes, if necessary.
Step 2: Start unwinding each coil. Take note of number of wraps and direction of winding. Each coil should have the same number of wraps. Be careful not to scratch or chip the epoxy coating beneath the wire. With a permanent marker, mark each core starting with the one above your scribe mark, 1, 2, 3, 1, 2, 3 and so forth in sequence (figure 1). .
Step 3: After all wire has been removed, inspect the stator closely, making sure the factory epoxy is not chipped or cracked. If any bad spots are present, you will need to put a small amount of epoxy to fill them in. If there are any spots you have doubts about, put a little epoxy on them, it's always better to be safe than sorry. Let dry completely.
NOTE: If you are like me, I can't keep count of all those wraps so to make it easier, I calculated the amount of wire by inches, and marked the wire where each coil would stop. It comes out to approximately 134 inches (11' 2"). These marks will not end up the same each time but as long as it is close it will work fine...
Step 4: Uncoil about 13 feet of wire (DO NOT CUT). Using masking tape, put a tag on end of wire and mark: #1 IN. Measure down 6 to 8 inches and make a mark with black marker. From that mark, measure another 11' 2" and make another mark. At the #1 core above the scribe mark, place the first black mark at the edge of the stator leaving the 6" to 8" sticking out. Start winding in a counter-clockwise direction, keep wire as tight and even as possible until you get to the 11' 2" mark. Pull the wire to the next #1core. From here, measure out another 11' 2" and make a mark with the marker. Wrap each #1 core in this way until all six have been wrapped. Measure out 6" to 8" and cut wire. On this end of wire using masking tape, mark: #1 OUT.
Step 5: Repeat Step 4 for the #2 and #3 cores.
Step 6: Now you should have six (6) wires protruding from the stator. Put the two wires marked
#1 IN and #3 OUT together and work them in between #1 and #3 cores above the scribe mark. Put the two wires marked #1 OUT and #2 IN together and cover with a piece of the cloth insulation from earlier. Work these wires between the #1 and #3 cores also. Put the two wires marked #2 OUT and #3 IN together and cover with cloth insulator. Work these wires between the #1 and #2 cores. Now you should have 3 sets of wires protruding to the case side of the stator.
Step 7: Using masking tape, tape every part of stator leaving nothing but the magnet wire showing. Apply epoxy, making sure all the wire is evenly covered. Leave the 3 sets of wires sticking out and uncoated. The epoxy should dry overnight.
Step 8: Once epoxy has dried, fold the three pairs of wires down toward the mounting screw for the clamp. Cut each pair even with the screw hole and with the wire strippers, strip a 1/4" of coating from the end of wire. Double check to see if the wires are still paired as in
Step 9: Slide the short cloth insulators over each pair. Soldier the three yellow wires to the 3 new ones and slide the cloth insulators over the connections. After installing the wire clamp you should feel you have a new stator.
Here are a series of emails I received about this article. I offer them as an FYI... Frank
I received an email from Blaine McKibbon. He believes the this article may be in error.
- Hi Frank,
- I will try to make this brief. I was thrilled to find GSRESOURCES. You guys are doing a stellar job. The stator papers series has given me the courage to rewind the stator on my dead 78 GS1000. I congratulate Gene and Kim Maynard for writing "How to rewind you own stator". However, there is at least one part of this paper that is dead WRONG. They suggest in step #6 to connect together #1 in to #3 out, #1 out to #2 in, and #2 out to #3 in as if to make one continuous circuit. This is contrary to every stator wiring diagram I have ever seen, as well as the way my own stator is wired.
- On my stator the In's of all three wires are connected together. The Out's remain separate and are attached to the colored wires that connect to the rectifier. This is consistent with the diagram in "Primer on GS charging systems". I doubt if a stator wired the way the Maynard's suggest would work at all.
- I counted 35 wraps of wire on each coil with the total length of each wire coming out to over 15'. The Maynard's suggest 11'2". However, this may vary from model to model.
- I will keep you posted as the project unfolds.
- Blaine McKibbin
I received this email from Fred Scott. He believes the Blaine is wrong and that this article is correct.
From the corners of the delta, the current is rectified just like normal.
- I just read over your excellent articles on the stator problems and felt I should comment.
- Blane's email to you states that the described method of rewinding the stator will not work. This is incorrect. There are two methods of stator winding. Blaine is used to seeing a "Y" wound stator. This is what you'll normally see in the books because it's easy for students to look at it and understand.
- The method that Gene describes will create what is known as a Delta wound stator. If you draw the three coils of the stator as a triangle with a lead coming off of each corner, you'll see why it is called that. It's difficult to picture current moving through all three sides of the delta at once, but if you draw out a diagram of a delta wound stator and rectifier, you'll see that no matter how which direction the current is running through each winding, it'll always have a path in and out via the wires at the corners of the delta. It may have to cross a second winding to find its path, but there's not a bit of harm in that.
It gives me a headache to try to picture current moving along all three legs at once, but believe me, it does work. Sincerely,
The Stator Papers I: APrimer on GS charging systems (youshould've read that first, it explains the theory referred to in this Q&A)
TheStator Papers II: FAQs
The Stator Papers III - The Solution, detailsabout the availability of the Electrex unit.
The Stator Papers IV - The Fault Finding Chart,a comprehensive, step-by-step fault findingprocedure.
The Stator Papers V - Cause #1 for failingcharging systems: bad conductivity!
The Stator Papers VI - How to rewind your ownstator