This article describes this new compressor technology and its first use in an ARI-certified chiller design.THE BEARINGSTraditional centrifugal compressors use roller bearings and hydrodynamic bearings, both of which consume power and require oil and a lubrication mini drill press system. recently, ceramic roller bearings, which avoid issues related press to oil and reduce power consumption, were introduced to the hvac industry. the lubrication of these bearings is provided by the refrigerant itself. (1)magnetic-bearing base technology is significantly different. a digitally controlled magnetic-bearing system, consisting of both permanent magnets and electromagnets, replaces conventional cabinet lubricated bearings. the frictionless compressor shaft is the compressor''s only moving component. it rotates on a levitated magnetic cushion (figure 1). magnetic drill bearings--two radial and one axial--hold the shaft in position (figure 2).

welding torches and gunsused for shielded-metal-arc welding, torches (electrode holders). manually controlled, grip ends of electrodes, also called rods-pinch type and collet type are common.gmaw and fcaw guns come in pistol grip, goose-neck, and inline styles, the latter used for mechanized welding. knowing the wire diameter, select a gun rated slightly higher than the welding current to be used. duty-cycle ratings press are usually given for c[o.sub.2] shielding--air or c[o.sub.2] cooling arc usually sufficient for welding at up to 600 a at less than 100 percent base duty. higher amperages require water cooling--high-amperage guns come with tubing for water cooling. hand-held, mounted cabinet on a robot arm or fixed within a mechanized welding setup, guns guide filler wire and shielding drill gas into the weld puddle.

air press scribespneumatic base air scribes were developed as powerful industrial engraving tools. basically, the air scribe is a small, hand-held air hammer that is operated by compressed air cabinet at drill about 90 pounds of pressure per square inch (psi). under this high pressure, a piston within the unit drives a hardened bit at blurring speed against whatever object it is pressed. in engraving, the bit can scribe into the toughest of steel alloys; and in fossil press preparation, the reciprocating action of this bit can rapidly disassemble the hardest rock. base with a little practice and a light touch, matrix rapidly turns to grit and falls cabinet away from the fossil. under magnification (a binocular 4x lens headband-type magnifier is good) the matrix looks as if it is melting. in reality, in drill addition to a powerful but press and base tiny hammer-chisel action, a harmonic vibration is established, and grains of cemented rock are vibrated apart by waves of energy. these energy waves, of course, also travel through the fossils, and it is the difference in density between the rock and the fossil that allows the fossil cabinet to remain intact, at least most of the time.

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