Lincoln Electric SVM128-A service manual WELDER/GENERATOR Maintenance

D-11 D-11

MAINTENANCE

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WELDER/GENERATOR

MAINTENANCE

STORAGE: Store the SA-250 in clean, dry, protected areas.

CLEANING: Blow out the generator and controls peri- odically with low pressure air. Do this at least once a week in particularly dirty areas.

NAMEPLATES: Whenever routine maintenance is performed on this machine - or at least yearly - inspect all nameplates and labels for legibility. Replace those which are no longer clear. Refer to the parts list for the replacement item number.

ALTERNATOR BRUSH REMOVAL AND REPLACE- MENT: It's normal for the brushes and slip rings to wear and darken slightly. Inspect the brushes when a generator overhaul is necessary. Remove the brushes and clean the slip rings with fine emery paper. To seat new slip ring brushes, position the brushes in place. Then slide one end of a piece of fine sandpaper between slip rings and brushes with the coarse side against the brushes. With slight additional finger pres- sure on top of the brushes, pull the sandpaper around the circumference of the rings - in the direction of rota- tion only - until brushes seat property. Brushes must be seated 100%.

COMMUTATOR AND BRUSHES: The generator brushes are properly adjusted when the welder is shipped. They require no particular attention.

CAUTION

DO NOT SHIFT THE BRUSHES or adjust the rocker setting.

Shifting of the brushes may result in:

•Change in machine output

•Commutator damage

•Excessive brush wear

Periodically inspect the commutator, slip rings, and brushes by removing the covers. DO NOT remove these covers while the machine is running.

Commutators and brushes require little attention. However, if they are black or appear uneven, have them cleaned by experienced maintenance personnel using a commutator stone. Never use emery cloth or paper for this purpose.

Replace brushes when they wear within 1/4" of the pig- tail. A complete set of replacement brushes should be kept on hand. Lincoln brushes have a curved face to fit the commutator. Have experienced maintenance personnel seat these brushes by lightly stoning the commutator as the armature rotates at full speed until contact is made across the full face of the brushes. After stoning, blow out the dust with low pressure air.

WARNING

Uncovered rotating equipment can be dangerous. Use care so your hands, hair, clothing or tools do not catch in the rotating parts. Protect yourself from particles that may be thrown out by the rotating armature when stoning the commutator.

Arcing or excessive exciter brush wear indicates a pos- sible misaligned shaft. Have an authorized Lincoln Electric Field Service facility check and realign the shaft.

BEARINGS: The SA-250 is equipped with double- shielded ball bearings having sufficient grease to last indefinitely under normal service. Where the welder is used constantly or in excessively dirty locations, it may be necessary to add one half ounce of grease per year. A pad of grease one inch wide, one inch long, and one inch high weighs approximately one half ounce. Over- greasing is far worse than insufficient greasing.

When greasing the bearings, keep all dirt out of the area. Wipe the fittings completely clean and use clean equipment. More bearing failures are caused by dirt introduced during greasing than from insufficient grease.

CURRENT RANGE SELECTOR CONTACTS: The contacts should not be greased. To keep the contacts clean, rotate the current control handle through its entire range frequently. Good practice is to turn the handle from maximum to minimum setting twice each morning before starting to weld. Never rotate the han- dle while machine is under load.

Put a drop of oil on the CURRENT RANGE SELEC- TOR shaft at least once every month.

RECEPTACLES: Keep the electrical receptacles in good condition. Remove any dirt, oil, or other debris from their surfaces and holes.

CABLE CONNECTIONS: Check the welding cable connections at the weld output terminals often. Be sure that the connections are always tight.

SA-250