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E-7

THEORY OF OPERATION

E-7

PULSE WIDTH MODULATION

FIGURE E.6 — TYPICAL FET OUTPUTS.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

sec

 

 

 

48

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sec

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

50

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MINIMUM OUTPUT

24sec

2 sec

 

 

 

24 sec

 

 

 

50sec

MAXIMUM OUTPUT

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The term PULSE WIDTH MODULATION is used to describe how much time is devoted to conduction in the positive and negative portions of the cycle. Changing the pulse width is known as MODULA- TION. Pulse Width Modulation (PWM) is the varying of the pulse width over the allowed range of a cycle to affect the output of the machine.

MINIMUM OUTPUT

By controlling the duration of the gate signal, the FET is turned on and off for different durations during a cycle. The top drawing above shows the minimum output signal possible over a 50-microsecond time period.

The positive portion of the signal represents one FET group1 conducting for 1 microsecond. The negative portion is the other FET group1. The dwell time (off time) is 48 microseconds (both FET groups off).

1An FET group consists of the sets of FET modules grouped onto one switch board.

Since only 2 microseconds of the 50-microsecond time period is devoted to conducting, the output power is minimized.

MAXIMUM OUTPUT

By holding the gate signals on for 24 microseconds each and allowing only 2 microseconds of dwell time (off time) during the 50-microsecond cycle, the output is maximized. The darkened area under the top curve can be compared to the area under the bottom curve. The more dark area under the curve, the more power is present.

V300-PRO

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Lincoln Electric SVM105-B service manual Pulse Width Modulation, Minimum Output, Maximum Output

SVM105-B specifications

The Lincoln Electric SVM105-B is a state-of-the-art welding machine that represents a leap forward in welding technology, designed for both professionals and enthusiasts in the welding industry. This versatile machine combines robust performance with user-friendly features, making it suitable for a wide range of welding applications.

One of the key features of the SVM105-B is its advanced inverter technology. This allows for a lightweight design without compromising on power output. The inverter technology ensures a stable arc and precise control, enabling consistent weld quality across various materials, including mild steel, stainless steel, and aluminum. This feature is particularly beneficial for users who demand exceptional performance in both thin and thick materials.

The SVM105-B also boasts an impressive output range, typically between 10A to 105A, allowing for adaptability to different welding tasks. Its ability to seamlessly switch between DC and AC modes makes it an ideal choice for professionals working in diverse environments, facilitating operations such as TIG and stick welding. This versatility is further enhanced by its compatibility with various electrode types, ensuring a more efficient and effective welding process.

User safety and comfort have not been overlooked in the design of the SVM105-B. Equipped with an efficient cooling system, this machine effectively manages heat during prolonged use, ensuring durability and longevity. Additionally, its intuitive digital display provides real-time feedback on settings, making it easier for users to monitor parameters and make necessary adjustments on the fly.

The SVM105-B is built with portability in mind. Its compact and lightweight design makes it easy to transport, enabling welders to bring their equipment to job sites without hassle. Furthermore, the machine features sturdy handles that contribute to its ease of maneuverability, supporting the demands of both inside workshops and outdoor projects.

Moreover, Lincoln Electric places a strong emphasis on quality and reliability, and the SVM105-B is a testament to this commitment. The machine is constructed from durable materials designed to withstand the rigors of daily use, ensuring it remains a staple in any welder's toolkit for years to come.

In conclusion, the Lincoln Electric SVM105-B stands out with its combination of advanced inverter technology, versatile output, user-friendly interface, and robust construction. Whether for professional or hobbyist use, this welding machine meets a wide array of welding needs while providing excellent performance and durability.