Lincoln SA Main Armatures-How and Why?
The most feared question I get is, " Is my Armature bad? In my opinion, the Lincoln OEM armatures SA200/250/300 and the various models have the same electrical style of main armatures.​​
I have been working in this industry since 1971, and I have a love/hate relationship with
Lincoln Electric. I admire their engineering, particularly the design of the older DC machines. These machines were created in a time when calculations were made by hand, without the aid ofcomputers, and I’m sure a lot of guesswork was involved in the process. They worked!
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The basic technology of a standalone generator, producing constant-current DC voltage,
is fed into a shunt coil to produce current using an engine-powered dynamo. The arc voltage has two "controls": 1) the "fine current control" (misnamed, but it still works!) and the arc length of the welding rod to the metal, controlled by the welder.
I am appalled by their manufacturing techniques and the materials they use. Exact historical dates from Lincoln are impossible to get. The dates in this thesis are all estimates. Somewhere in the late 1980s, the EPA outlawed the L-head (flathead) engine.
There is no wire on the armature. Wire is circular in shape. The armatures are wound with various sizes of rectangular conductor, called "ribbon." This shape is critical in producing magnetic fields.
There are three ribbons in each slot. They are soldered to three separate bars on the commutator. Then wrap around the armature, into a channel 180' opposite the original channel, and so, directly soldered to three opposing bars on the other side of the commutator. The three ribbons cannot ever touch! If they come into contact, they will short. The first sign is that your weld puddle will change, and there is nothing you can do to stop it. This is why it is so important to do everything possible to keep them separate!
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I understand that when you are manufacturing a machine for a large market, you have to balance quality with profitability. Lincoln has always cut corners where the customer cannot see them, and they have gotten away with it. I've seen these armatures that are 75 years old, look like hell, ohm out, and still run! The rule of thumb is 1 meg or more of resistance from each commutator bar to the shaft. I have seen them weld with 500k of resistance. I don't know how!
1. Lincoln used different sizes of copper ribbon for different machines.
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2. Just varnish separates the three copper ribbons in each channel.
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3. The copper ribbon is insulated from the armature core with paper. What happens to paper when it gets wet?
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3. The ribbons are held in place with welding wire, which works great until it doesn't! When you combine steel and moisture in a strong magnetic field, you get electrolis. This is corrosion, stimulated by an electric current. Add in sulphur, from a leaking rear main seal. You have sulphuric acid to add to the problem. When they fail, the centrifugal force rips the winding out. If you don't stop the machine in time, it will destroy the armature and stator housing. The image to the right is an armature we replaced. He destroyed his armature and the obsolete stator housing; we took care of him.
Why You Should Invest Your Hard-Earned Money in a Weldmart Rewound Main Armature?
1. It;s expensive. You only want to do it once!
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2. They are obsolete from Lincoln, and only carry a 1-year warranty if replaced by an authorized, certified, sanitized Lincoln Service Center. The machines are older than the tech!
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3. Weldmart warrants our rewounds for 10 years from the date of purchase by the original customer.
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4. Weldmart warrants our rewounds for the life of the original customer. It fails you. Please bring it back. We want to know why.
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5. We have been selling and installing these armatures for over thirty years, no claims!
Why Can We Do This?
1. All our rewound armatures are 300 amp armatures; drop one into your 200 or 250 amp machine. No matter how you look at it, it's a significant upgrade!
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2. All our copper ribbon is coated with a layer of fiberglass fiber, not just the original varnish.
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3. The material insulating the ribbons from the armature core is not paper; it's a very tough, flexible piece of composite insulation. It will not absorb water.
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4. The ribbon winding are held in place with DuPont insulation strip, which is secured with fiberglass bands, they are impervious to water.
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How to Order a Rewound Armature?
In our opinion, this is too big a purchase to make blindly on the net.
1. Call our office, about 25% of my customers looking for an armature have other problems, not their armature.
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2. If we sell you, we need your core; it is not available anymore.
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3. We'll send you a rewound armature in a wooden crate. You will be charged a core charge and a box charge. Put your core in the box and send it back to us. We will refund your core and box charge.
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4. Call us, we want to talk to you. We need your code number. ​​​​​
