High frequency surge tester methods and apparatus
AssigneeAxis AB
InventorsCarlo Domenichini, Massimo Linari
Life of this patent
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Abstract
A high frequency surge tester includes a high frequency detection circuit which is used to detect microfracture defects in the insulation of wire on wound coils. The high frequency detection circuit includes a high-pass filter which isolates an errant voltage response so that it can be integrated and compared to threshold limits to determine the magnitude of defects. The surge tester also detects shorts between coils and shorts between turns of the same coil.
Claims18
A surge tester for testing an input signal generated by a wound coil during manufacturing of a wound coil device comprising:
- a predetermined voltage source having a positive and a negative terminal;
- a resistor;
- a microprocessor having processing means;
- a first switch connected in series between said resistor and a first of said positive and negative terminals of said predetermined voltage source;
- a second switch connected in series between said resistor and one end of said wound coil being tested, with the other end of said wound coil being connected to a second of said positive and negative terminals of said predetermined voltage source;
- a capacitor connected in series between a node in the series connection of said resistor and said second switch, and said second of said positive and negative terminals of said predetermined voltage source;
- and
- a high frequency analysis circuit which extracts and modifies a high frequency component from said input signal, connected in series between said microprocessor and a node in said series connection of said second switch and said one end of said wound coil, said modified high frequency component being of a substantially higher frequency than the relatively low frequency main response of said coil, and wherein said processing means analyzes said modified high frequency component in order to detect microfracture defects in the insulation of a wire in said wound coil.
A method for detecting defects in a wound coil during the manufacturing of said coil comprising the steps of:
- connecting said coil to a surge tester;
- subjecting said coil to an electrical surge in order to cause an oscillatory response in said coil;
- sensing said oscillatory response of said coil;
- using a microprocessor to analyze a high frequency component of said oscillatory response of said coil in order to detect microfracture defects in the insulation of a wire in said wound coil, said high frequency component being of a substantially higher frequency than the main oscillatory response of said coil.
Dependencies are inferred from the claim text.