Kamath G.R.,Hypertherm Inc.
2014 IEEE International Conference on Power Electronics, Drives and Energy Systems, PEDES 2014 | Year: 2014
This paper presents an analysis of the skin and proximity effects produced by line frequency harmonic currents in a 33 kW 12-pulse rectifier transformer using its 'Double-2D' FEA model. The model is first validated with experimental data obtained from a series of standard impedance voltage tests with a proof-of-concept transformer prototype. Good agreement is observed between model results and experimental data. The model is then used to study the 12-pulse harmonic current conditions and represent the associated winding losses as equivalent resistances. It is seen that harmonic current losses account for as much as 8-11% of the secondary winding and 4-6% of the total winding power loss, indicating their significance in this application. © 2014 IEEE. Source
Plasma, oxyfuel cutting, and laser - The selection of the process best adapted to satisfy the exigencies of the cutting of metals [Plasma, ossitaglio e laser - La scelta dei processo più adatto per soddisfare le esigenze di taglio dei metalli]
McQuade K.,Hypertherm Inc.
Rivista Italiana della Saldatura | Year: 2010
When it comes to cutting metal, there are several options; important is figuring out which option is right for your business. Choosing the right process is dependent upon the cutting needs of your business: cut quality, productivity, operating costs, profitability, process flexibility or investment costs. This article explores the three major thermal cutting technologies - oxyfuel, laser and plasma - and provides insight into what is important to consider when deciding which cutting process would be best for you. Source
McQuade K.,Hypertherm Inc.
Welding and Cutting | Year: 2010
Back to the original question as to which process is the best. Hopefully the answer "it depends" now makes sense as it does depend on each specific cutting operation. Laser is often used when cutting thin plate (less than 6 mm) and where tight tolerances are required. The capital cost and operating cost are both high. Oxyfuel is mainly used for cutting only thick carbon steel (greater than 50 mm) when cut quality is not a requirement. Oxyfuel has the lowest capital cost and operating cost, but the cost per part is higher due to slow cutting speeds and lower quality which often requires rework.Plasma provides a good balance in terms of capital cost, cut quality, productivity and operating cost. It has a broad thickness range, material flexibility and provides high cutting speeds. Source
Osterhouse D.J.,University of Minnesota |
Lindsay J.W.,Hypertherm Inc. |
Heberlein J.V.R.,University of Minnesota
Journal of Physics D: Applied Physics | Year: 2013
Plasma arc cutting is a widely used industrial process in which an electric arc in the form of a high velocity plasma jet is used to melt and blow away metal. The arc attaches inside the resulting cut slot, or kerf, where it both provides a large heat flux and determines the flow dynamics of the plasma. Knowledge of the position of the arc attachment is essential for understanding the phenomena present at the work piece. This work presents a new method of measuring the location of the arc attachment in which the arc voltage is measured during the cutting of a range of work piece thicknesses. The attachment location is then interpreted from the voltages. To support the validity of this method, the kerf shape, dross particle size and dross adhesion to the work piece are also observed. While these do not conclusively give an attachment location, they show patterns which are consistent with the attachment location found from the voltage measurements. The method is demonstrated on the cutting of mild steel, where the arc attachment is found to be stationary in the upper portion of the cut slot and in reasonable agreement with existing published findings. For a process optimized for the cutting of 12.7 mm mild steel, the attachment is found at a depth of 1.5-3.4 mm. For a slower process optimized for the cutting of 25.4 mm mild steel, the attachment is found at a depth of 3.4-4.8 mm, which enhances heat transfer further down in the kerf, allowing cutting of the thicker work piece. The use of arc voltage to locate the position of the arc attachment is unique when compared with existing methods because it is entirely independent of the heat distribution and visualization techniques. © 2013 IOP Publishing Ltd. Source
Hypertherm Inc. | Date: 2010-08-10
Communications software for computer controlled plasma arc cutting or welding systems that facilitates the programming of computer numerical controls, cutting profiles, or shapes.