Section TOC

Master TOC

E-4

TROUBLESHOOTING & REPAIR

E-4

 

 

 

FIGURE E.4 – SCR BRIDGE, RESISTOR BANK, FIRING BOARD, & OUTPUT CAPACITOR/RESISTOR

Return to

to Section TOC

Return to

to Master TOC

SURGE

NOISE

FILTER

INPUT

CONTACTOR

R E C O N N E C

T T2

CONTROL

TRANSFORMER

THERMOSTAT SWITCH

CONTROL

BOX

RECTIFIER

CONTACTOR

VAC 120

FAN VOLTAGE

T1

MAIN

TRANSFORMER

SCR OUTPUT RECTIFIER

 

 

 

SHUNT

 

 

 

TO CONTROL

 

 

 

BOARD

 

 

 

GATE SIGNALS

32 VAC

32 VAC

32 VAC

 

 

 

RESISTOR

FIRING

 

 

BANK

BOARD

WORK

TERMINAL

FILTER

CAPACITOR

LIMITING

RESISTOR

ELECTRODE

TERMINAL

TO CONTROL

BOARD

Return

Return to Section TOC

Return to Section TOC

Return

Return to Master TOC

Return to Master TOC

CONTROL

 

 

BOARD

 

CONTROL

FAN

THERMOSTAT

SIGNAL

G Y

W

 

DIGITAL

 

 

METER

LED LED LED

 

SCR BRIDGE, RESISTOR BANK,

FIRING BOARD, AND OUTPUT

CAPACITOR/RESISTOR

The neutrals of the main transformer secondary wind- ings are connected together and the six starts are con- nected to the six SCR assemblies to form a six phase output. This six phase AC output is rectified and con- trolled through the SCR bridge.

The firing board receives power through the current limiting resistor bank. The firing board is a three phase circuit. Each phase provides two firing pulses; one for each of the two Silicon Controlled Rectifiers (SCRs) controlled by that particular phase. The firing circuit supplies the proper amount of energy to the gates of the power SCRs. When the gate signal is applied, at the correct time, the SCR will turn on and conduct cur- rent. The amount of "ON" timer versus "OFF" time determines the output of the machine. See SCR

Operation.

A capacitor filter and resistor are connected across the output leads on the Multi-Source. This is required to reduce and limit the output voltage peaks. The capac- itor ripple current (greatest with light resistive loads) is limited by the resistor.

MULTI-SOURCE

Page 26
Image 26
Lincoln Electric SVM155-A service manual Operation

SVM155-A specifications

The Lincoln Electric SVM155-A is a state-of-the-art welding machine that excels in versatility and performance, making it ideal for both professional welders and hobbyists. This multi-process welder supports MIG, TIG, and stick welding processes, allowing users to tackle a wide range of applications with a single device. Its user-friendly design and advanced technology make it an exceptional choice for those looking to enhance their welding capabilities.

One of the main features of the SVM155-A is its robust power output, which can handle welding materials ranging from thin sheets to heavier stock. The welder offers a high duty cycle, ensuring that users can work efficiently without the need for prolonged breaks. This is especially important in industrial settings where productivity is key. Additionally, the SVM155-A is equipped with a digital display that allows for easy monitoring and precise control of the welding parameters, ensuring consistency in weld quality.

The European-designed INVERTER technology embedded in the SVM155-A significantly contributes to its lightweight and compact design. Weighing in at only 19.4 lbs, this welder is portable and ideal for fieldwork or workshops where space is limited. The inverter technology not only reduces the size and weight but also improves energy efficiency, leading to lower operational costs over time.

The SVM155-A also features advanced safety mechanisms, including over-current protection to safeguard the machine from potential damage during excessive use. It also includes a thermal overload shut-off, which prevents overheating, ensuring a longer lifespan for the welder.

Another standout characteristic of the SVM155-A is its exceptional arc stability and ease of use. The machine is designed to provide a smooth and consistent arc, reducing spatter and ensuring clean welds. Moreover, the welder is compatible with a wide range of materials, including stainless steel, aluminum, and carbon steel, further enhancing its versatility.

In conclusion, the Lincoln Electric SVM155-A is a powerful, durable, and multifunctional welding machine that incorporates advanced technologies to meet the needs of modern welding applications. Its portability, safety features, and ability to deliver high-quality welds make it an excellent investment for anyone looking to improve their welding skills or expand their capabilities in various welding projects.