US Patent: 4,402,032
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| Electromagnet Power Supply and Demagnetizer
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Patentee:
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| Bernard W. Wilterdink (exact or similar names) - Claremont, Sullivan County, NH |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Mar. 12, 1981 |
| Granted: |
Aug. 30, 1983 |
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Joel Havens
"Vintage Machinery" entry for Cone Automatic Machine Company
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Description: |
| Abstract:
An electronic current control device for energizing and de-energizing an electromagnet, such as a magnetic chuck, includes a DC power source preferably in the form of a phase-controlled SCR power unit. A conduction angle control signal is routed to positive or negative gates in the power unit to determine polarity and amplitude of direct current through the electromagnet windings. In the "on" mode an analog current feedback loop maintains a predetermined magnetizing level of current through the windings. In the demagnetize mode, a digital system decreases the current amplitude stepwise while alternating the polarity. When the sensed current attains the selected peak level for a given step, a digital count is decremented. The polarity is reversed according to the odd or even count, and a new peak reference level is established corresponding to the digital count. |
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