Shunt Coils Troubleshooting and Repair Guide for Lincoln Electric Welders

TROUBLESHOOTING AND REPAIR

F-50

SHUNT FIELD COIL RESISTANCE AND GROUND TEST (continued)

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PROCEDURE

1.Turn the engine off.

2.Open both of the doors on the control panel end of the SAE-400 machine. The roof may also need to be removed on some models.

WARNING: Secure the doors in the open position using the door restraint system. If the machine does not have a door restraint system, remove the doors or securely restrain them to prevent them from falling closed.

Shunt Coil Resistance Test:

3.Place the polarity switch in the “OFF” position. Locate the 500 Ohm/50 Watt resistor located on the back of the control panel, just below the 115 VAC duplex receptacle. Leave all of the leads connect- ed to the resister, and measure the resistance

acrossit. The resistance should measure approximately

36.5* ohms at 77°F. (25° C.)

If the resistance reading is correct, proceed to the Shunt coil ground test.

•If the resistance reading is slightly high, about 40* Ohms, The 500 Ohm resistor may be open.

•If the resistance is significantly higher than 40* Ohms, check the wiring between the test points and the shunt coils. Check the lead connecting the two shunt coils together inside the generator frame. See the wiring diagram and the internal generator diagram. If these wires and connec- tions are undamaged, one of the coils is likely open. Replace the shunt field coil set.

•If the resistance is significantly lower than 36.5* Ohms at 77°F. (25° C.), check the wiring between the test points and the coils for damaged insula- tion, pinched wires, etc. If the wires and insula- tion are in good condition, disconnect at least one of the shunt coil wires from the resistor and test the resistance of just the shunt coil set. See the wiring diagram and internal generator diagram. If the resistance is still significantly lower than 40 Ohms, one of the coils is likely shorted. Replace the shunt coil set.

Shunt Coil Ground Test:

4.Place the polarity switch in the “OFF” position. Locate the 500 Ohm resistor located on the back of the control panel, just below the 115 VAC duplex receptacle. Leave all of the leads connected to the resistor, and measure the resistance between either of the resistor terminals and a good clean chassis ground. The resistance should be very high, 500,000 (500k) Ohms minimum.

•If the resistance is too low, disconnect the shunt coil leads from the resistor and position them so they cannot make electrical contact with any- thing. See the wiring diagram. Test the resis- tance between either of the shunt coil lead wires and a good, clean chassis ground.

•If the resistance is still lower than 500,000 (500k) Ohms, check the shunt coil leads between the test points and the coils. Also check the lead connecting the two shunt coils together inside of the generator. Look for pinched wires and dam- aged insulation. If the low resistance is deter- mined to be between chassis ground and one of the shunt coils, replace the coil set.

•If the coil set tests normal when disconnected, check the resistor and polarity switch for low resistance to chassis ground. Repair or replace these parts as needed.

5.Reconnect the wires and replace any covers that have been removed.

*NOTE: The resistance of the copper windings will change with temperature. Higher tempera- tures will produce slightly higher resistance, and lower temperatures will produce slightly lower resistance.

SAE-400 SEVERE DUTY

SVM187-A specifications

The Lincoln Electric SVM187-A is a cutting-edge welding machine designed for professional welders and industrial applications. Known for its reliability and performance, it stands out in the competitive welding equipment market. This versatile machine is structured to handle various welding processes, making it a popular choice among users.

One of the primary features of the SVM187-A is its multifunctional capabilities. It supports MIG, TIG, and Stick welding, allowing users to switch between different welding techniques seamlessly. This flexibility makes it suitable for diverse applications, whether working on automotive repairs, metal fabrication, or construction projects. Additionally, the machine is equipped with a robust power output, ranging from low to high amperage settings, enabling users to tackle a wide array of materials, including mild steel, stainless steel, and aluminum.

The SVM187-A incorporates advanced inverter technology, which ensures increased efficiency and reduced energy consumption. This technology leads to a more compact design, making the unit portable and easy to transport. The lightweight construction of the machine does not compromise its durability; it is built with high-quality materials to withstand the rigors of a professional workshop.

Another notable characteristic of the SVM187-A is its user-friendly interface. The intuitive control panel includes digital displays for precise settings adjustments, ensuring accuracy during operation. Beginners and seasoned welders alike can benefit from the clear and straightforward design, reducing training time and enhancing productivity.

Safety features are paramount in the SVM187-A's design. The machine is equipped with thermal overload protection, ensuring that it operates within a safe temperature range to prevent damage and promote longevity. Additionally, it features automatic voltage regulation, which maintains a stable arc even under varying input voltage conditions.

In summary, the Lincoln Electric SVM187-A is a versatile, efficient, and user-friendly welding machine suited for both professional and industrial applications. Its multifunctionality, inverter technology, and robust safety features set it apart from competitors, making it a reliable choice for welders seeking to elevate their craftsmanship while ensuring safety and efficiency. This machine represents the innovation and quality that Lincoln Electric is renowned for in the welding industry.

Lincoln Electric Essential Guide for Troubleshooting and Repairing Shunt Coils in Welders

Models: SVM187-A

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