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E-4

THEORY OF OPERATION

E-4

 

FIGURE E.2 - GENERAL DESCRIPTION

 

ELECTRODE

TERMINAL

OUTPUT

CONTROL

MIN

MAX

(OFF)

 

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THERMOSTART

 

 

BUTTON

 

 

TO IDLE / ENGINE

 

 

PROTECTION BOARD

 

TO IDLE/ENGINE

 

 

PROT. BOARD

 

 

 

 

S

 

 

T

 

 

A

 

 

R

 

STARTER

T

 

SOLENOID

E

 

 

R

RUN/STOP

IDLE SWITCH

SWITCH

 

 

 

HOUR

 

AMMETER

METER

 

 

 

TO

 

 

FLASHING

START

RESISTOR

AND

 

BUTTON

 

DIODE

 

 

 

 

AC

 

 

 

 

 

(-)

(+)

 

 

 

 

AC

 

 

 

 

 

 

REMOTE

 

 

 

 

 

RHEOSTAT

LOCAL

 

 

 

 

 

 

 

 

 

POLARITY

RHEOSTAT

 

 

 

 

(JOB SELECTOR)

 

 

 

 

SWITCH

 

 

 

 

RESISTOR

 

(+)

 

 

 

SHUNT COILS

 

 

 

 

 

(-)

 

 

THERMOSTAT

 

 

 

 

INJECTION

SERIES COILS

 

 

 

 

PUMP

 

 

EXCITER

 

 

SOLENOID

 

 

WINDING

(-)

(+)

SYSTEM

GENERATOR

 

 

DIESEL

 

EXCITER

 

 

ARMATURE

 

ROTOR

 

 

ENGINE

 

 

 

 

 

 

 

 

 

AUXILIARY

POWER

WINDINGS

OIL

INTERPOLE COILS

 

PRESSURE

TEMP

SWITCH

SWITCH

IDLE

 

SOLENOID

 

 

115 VAC

IDLE / ENGINE

RECEPTACLES

PROTECTION BOARD

 

ENGINE TO ALTERNATOR

FAULT

LIGHT FLASH/SENSE

TO INJECTION

PUMP SOLENOID

FLASHING

 

TO HOUR METER

RESISTOR AND

DIODE

230VAC RECEPTACLES

WORK

TERMINAL

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EXCITER/AUXILIARY ALTERNATOR OPERATION

The exciter alternator is the smaller power generator that is located at the end of the main welding genera- tor. It provides power to energize the rotor, the shunt fields of the main welding generator and about 3 KVA of 120/230 volts, 60 Hz. for auxiliary power.

Flashing:

The exciter alternator requires that DC power be applied to the slip rings to start the power generation process. This DC power is often referred to as “Flashing” voltage, and originates at the battery. This voltage is applied through the Idler/Engine Protection PC Board, whenever the fuel solenoid is open and the hour meter is running.

The flashing current passes through a blocking diode and current limiting resistor before being applied to the rotor field winding through the positive brush and slip ring. The current then passes out of the negative slip ring and brush, through two diodes, and back to the battery through a chassis ground connection.

Building output:

The flashing current produces a weak magnetic field in the rotor, which is coupled to the now running engine. This rotating magnetic field begins to generate AC out- put from all of the stator windings. Output from the exciter winding is rectified by a diode bridge, and then fed back into the rotating field winding, through the brushes, making the magnetic field stronger. This stronger magnetic field then produces higher voltage from the stator windings, which feeds back to the rotor, making its magnetic field even stronger.

This process of strengthening the magnetic field through feedback from the exciter winding continues to increase the output of the alternator until the design voltage is reached.

The field voltage is now considerably higher than the flashing voltage that was used to start the generating process. The diode in the flashing circuit now blocks that higher field voltage from intruding into the 12VDC battery system and the machine chassis.

(continued on next page)

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NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion

SAE-400 SEVERE DUTY

Page 34
Image 34
Lincoln Electric SVM187-A service manual EXCITER/AUXILIARY Alternator Operation, Flashing, Building output

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.