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Eddy Current Testing
Crack Detection and Sorting Unit

Portable, Solid State, Variable Frequency Instrument Featuring CRT Readout with Memory Display and Dual Box Gates

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The Model ED-800 instrument is an eddy current test unit which will locate and measure the severity of surface and near-surface discontinuities in both magnetic and non-magnetic conductive materials. In addition, the ED-800 will sort both classes of metallic materials according to such properties as conductivity, hardness, alloy type, and carbon content, heat treat condition, tensile strength and grain structure. It will also measure thickness of conductive and nonconductive coatings and of thin sheets. With built-in accessory gating, the unit may be used in fully automatic or semi-automatic modes.

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The one button balancing feature substantially reduces set up time for manual operation and application studies. The solid state memory allows the operator to record selected patterns on the CRT screen. Subsequent operation of the unit in the "non-store" mode will not affect the recorded patterns. This allows the operator to compare test readouts with pre-recorded "standards." These capabilities, combined with the light weight, small size and battery operation of the unit, make the ED-800 a most versatile instrument.

The ED-800 instrument consists of solid-state circuitry, printed circuit boards, cathode ray tube, and battery, housed in an aluminum case with stainless steel handle that swings around the instrument from top to bottom. The handle locks in any of 11 positions for ease of carrying and tilting the instrument on flat or curved surfaces for convenient viewing of the CRT readout.

The following controls are located on the front panel:

On-Off/Power: Two position On-off toggle switch.
Focus and Intensity: Permit operator to optimize CRT presentation.
Store/Non-Store: Selects memory function to hold data on CRT screen.
Erase: Clears the memory and the display.
Frequency: Coarse and Vernier calibrated controls for continuously variable frequency over entire range.
Sensitivity: Varies the gain of the instrument over a range of 100:1.
Phase: Allows rotation of display 0?to 360?
Probe drive: Controls power to the probes. Overload indicator lights when power setting is too high for best performance.
Impedance: Matches the instrument to the probes in use for optimum performance.
Push to balance: Re-balances the instrument, moves dot display to preset location on CRT.

A recessed area on the top surface of the instrument, with a hinged and latching cover, houses additional controls:

Balance: For manual balancing of the instrument.
Mode: Selects any of three balance modes: Manual, Hold, or Auto.
Position: Locates dot position on CRT when instrument is balanced.
Expand: Increases only the vertical sensitivity to magnify the phase separation of signals.
Box Gate: Concentric controls used to adjust the vertical and horizontal size and position of the box gate area.

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The ED-800 is an eddy current instrument which is capable of using any of a wide variety of probes and coils. Probes with one or two windings and coils with one, two or three windings may be used. (Note: when using single winding probes or coils, they must be used in pairs to maintain system balance.) Vernier frequency adjustment, probe drive and impedance adjustments allow the operator to optimize system performance for whatever probes or coils are selected.

An available Battery Eliminator permits continuous line operation of the instrument and eliminates the need for periodic replacement of battery packs. This Battery Eliminator may be selected in place of battery and charger at the time of purchase, without additional cost. Single phase 115V or 230V (Specify), 50-60 Hz.

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This type of automatic gating permits simplified discrimination between signals produced by most defects and those produced by unimportant variations in the part being tested. With the "flying dot" display, changes in phase or amplitude in eddy currents are reflected by movement of a spot on the CRT screen. With the box gates, an illuminated, box-shaped area variable in size and location, is presented on the screen. Using a sample part with a known flaw, the box may be positioned on the screen so that the flying dot enters the box area when deflected by the flaw signal. Entry of the dot triggers the gate, producing a signal which can set off a visual or audible alarm, or trigger automatic rejection of a defective part, for later examination. Thus, only defects of a known type or severity will be detected.

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Case dimensions: 5 1/4" x 11" x 13" (13.3cm x 27.9cm x 33cm)
Weight: 16 lbs. (including battery pack) (7.26 kg)
Frequency range: 100 Hz to 2.5 MHz
Power Requirements: Battery: rechargeable nickel-cadmium
Line: 115 or 230 VAC. single phase, 50/60 Hz, with battery eliminator
Battery Charger: Operates from 115 or 230 VAC, single phase, 50/60 Hz.
Readout: CRT Screen with flying dot display, ruled graticule.
Environmental Capability: Temperature range - 0?to 120F at 85% RH.