Robert W Schultz

US Patent:

47516089, Jun 14, 1988

Filed:

Oct 14, 1986

Appl. No.:

6/918351

Inventors:

Robert A. Schultz - Chicago IL

Assignee:

Data Security, Inc. - Lincoln NE

International Classification:

H01F 1300
H01H 4700

US Classification:

361151

Abstract:

A bulk degausser for erasing a reel of high energy magnetic tape. The degausser includes a circuit for generating magnetic fields including a coil defining a window for passage of the reel of tape. The coil includes a first winding having relatively few turns and a second winding, inductively coupled to the first winding, having relatively many turns. The circuit also includes an ac power supply connected to the first winding and a dc power supply connected to the second winding. A resonance capacitor is interconnected with the second winding for substantially balancing the inductive reactance of the second winding at the frequency of the ac power supply. The circuit also includes an isolation relay, interconnecting the capacitor and the second winding with the dc power supply, for isolating the dc power supply when the first winding is energized by the ac power supply. Energization of the second winding by the dc power supply causes a tape in said window to undergo a dc magnetic field, and energization of the first winding by the ac power supply induces ac current in the second winding resulting in a reel in said window experiencing an ac magnetic field. A drive mechanism for translating and rotating the reel of high energy magnetic tape with respect to the coil, is also disclosed.

US Patent:

57216657, Feb 24, 1998

Filed:

Aug 18, 1995

Appl. No.:

8/516723

Inventors:

Robert A. Schultz - Chicago IL

Assignee:

Data Security, Inc. - Lincoln NE

International Classification:

H01F 1300

US Classification:

361149

Abstract:

A bulk degaussing system for bulk erasure of various magnetic media includes a source of magnetic flux for generating a magnetic field with a predetermined field strength within a predetermined volume defining a predetermined degaussing window, a transport system for transporting the magnetic media relative to the degaussing window such that every point on the magnetic media is exposed to the magnetic field. A control circuit is included which modulates the magnetic field to reduce power consumption. In addition to reducing power consumption, the modulated magnetic field minimizes system performance degradation due to stalls of the magnetic media transport system due to interactions between the magnetic field and ferromagnetic components associated with certain magnetic media.