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F-29

TROUBLESHOOTING & REPAIR

F-29

 

 

 

 

 

ACTIVE SCR TEST (Continued)

 

 

 

 

FIGURE F.13. SCR Test Setup

 

 

 

 

 

 

 

 

SW1

R2

 

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V

R1

6 VOLT

 

A

LANTERN

SCR

G

BATTERY

UNDER C

TEST

SW2

R1= 4 ohms/10 watts R2= 3 ohms/10 watts

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To test SCRs construct the circuit outlined above. Resistor values are plus or minus ten percent. The voltmeter scale should be low, approximately 0-5 or 0-10 volts DC.

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7.To test SCRs, construct the circuit outlined in Figure F.13. Use one 6V lantern battery. Resistor values are in ohms +/- 10%, The voltmeter scale should be low, approxi- mately 0-5 or 0-10 volts.

BATTERY TEST

Check the battery by shorting leads (A) and

(C)and then close switch SW1. Replace bat- tery if voltage is less than 4.5 volts.

A. Connect SCR into the test circuit as shown (A) lead to anode (C) lead to cath- ode and (G) lead to the gate.

B. Close switch SW1 (switch SW2 should open), voltmeter should read zero. If the voltmeter reads higher than zero than the SCR is shorted.

NOTE: Do not disassemble the heat sinks.

8.With switch SW1 closed, close switch SW2 for two seconds and release. The

voltmeter should read 3 to 6 volts before and after switch SW2 is released. If the voltmeter does not read, or reads only while SW2 is depressed, the SCR or bat- tery is defective (repeat battery Test Procedure).

9.Open switch SW1, disconnect the gate lead (G) and reverse the (A) and (C) leads on the SCR. Close switch SW2. The volt- meter should read zero. If the voltage is higher than zero, the SCR is shorted.

10.Replace any SCR assembly that does not pass test.

11.When test is completed, reconnect the positive bridge leads to the shunt.

12.Reconnect Plug J4 into the Firing Board.

13.Replace the case top, sides and control panel.

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MULTI-SOURCE

Page 57
Image 57
Lincoln Electric SVM155-A service manual SW1

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.