Tech Talk: Fast Switch Technology Cuts Weight, Boosts Portability

(As seen in Applied Welding, Issue 4, 2003)

Q: What is Fast Switch Technology?

A: A basic premise of welding power source design is that a faster operator frequency enables the power source to use fewer copper windings and a smaller core in its transformer and inductor.

Q: Why is that important?

A: Miller Electric Engineers developed Fast Switch technology as part of ongoing efforts to design smaller, lighter and more powerful per-pound welding power sources. Fast Switch technology enabled Miller to remove weight without sacrificing low-end arc performance or the high-end power of 150 amps of TIG output at 50 percent cycle.

Q: What are the specs for a Fast Switch Inverter power source?

A: Miller’s Maxstar® 150 Series of inverters weigh just 13.7 lbs., have a 5- to 150-amp welding range, provide best-of-class arc performance and run on 115 to 230 VAC primary power. Further, it is the only machine that can run a 1/8-in. E7018 electrode on 115 VAC input. [Editor note: The Millermatic® Passport™also features Fast Switch technology.]

An operator TIG welds stainless steel with a Maxstar 150 Series inverter featuring Fast Switch technology.

Q: What’s the frequency for products based on Fast Switch?

A: They operate at a frequency of 100,000 Hz (100 kHz). That’s two to five times faster than traditional inverter or chopper technology and more than 1,000 times faster than conventional welding technology.

Q: What are the advantages of Fast Switch technology? 

A: Reducing the size and weight of a welding power source increases its portability and convenience. Given that labor accounts for 85 percent of a finished weld’s cost, portable Fast Switch inverters make good business sense. The operator can quickly bring the equipment to the work site to complete jobs faster.

Other advantages include: the ability to obtain superior Stick welding performance with all electrode types; quick response to changing arc conditions; superior control over pulsed welding processes; better power factor; and less susceptibility to primary voltage fluctuations.

Q: What types of industries would benefit from portable inverters? 

A: Mechanical contracting, food/beverage, aerospace, shipbuilding, petrochemical, dairy, maintenance/repair, construction and hobby/light fabrication are among industries that would benefit from Fast Switch technology.

Q: What about the reliability rating of Fast Switch inverters? 

A: They should exceed the reliability of existing inverters, and inverters such as Miller’s Maxstar TIG/Stick products already set the industry standard for reliability in their category. Fast Switch increases reliability because it reduces the stress on the power switching semiconductor, called an IGBT. Miller engineers developed new circuits, cooling mechanisms and other techniques so that IGBTs are living in luxury compared to competitive designs.

That’s why Miller inverters lead long, stress-free lives. Miller also develops its duty-cycle rating at an ambient temperature of 40 degrees C to ensure continuous performance in hot weather conditions.