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Field and Armature Control in a Reel Motor Servomechanism

IP.com Disclosure Number: IPCOM000079812D
Original Publication Date: 1973-Sep-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 3 page(s) / 48K

Publishing Venue

IBM

Related People

Cope, JR: AUTHOR [+2]

Abstract

In a magnetic tape unit having vacuum column buffers which isolate a centrally located, low-inertia capstan from two variable-inertia tape reels and their high-inertia DC motors, means are provided for servo controlling both the reel motor's armature and its field, in order to maintain the reels under control without excessive length vacuum columns and without excessive reel motor power.

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Field and Armature Control in a Reel Motor Servomechanism

In a magnetic tape unit having vacuum column buffers which isolate a centrally located, low-inertia capstan from two variable-inertia tape reels and their high-inertia DC motors, means are provided for servo controlling both the reel motor's armature and its field, in order to maintain the reels under control without excessive length vacuum columns and without excessive reel motor power.

Tape motion in the tape unit of the figure is under primary control of capstan
10. The latter initiates tape movement and disturbs the position of loops 11 and 12 in columns 13 and 14, respectively. As a result of loop movement, the armatures of DC reel motors 15 and 16, receive servo commands to rotate reels 17 and 18 in a direction to reposition the loops. Control of tape motion is provided by conductors 19 and 20. Capstan servo 21 is controlled by the motion commands to energize capstan motor 22 so as to provide the required direction of rotation, and to maintain the rotational speed of motor 22 at a predetermined steady state value.

On the figure only the servo structure for motor 15 is shown, it being recognized that an identical structure is provided for motor 16.

The motion commands are also supplied to control motors 15 and 16, by way of conductors 23 and 24. Armature servo 25 responds to the capstan start command and the capstan direction command and is effective to energize the armature of motor 15, so as to cause the latter to begin rotating to move tape in the direction of capstan tape motion. Servo 25 also receives input information by way of conductor 26 as to the condition of loop 11 sensed by tape loop sensor
27. Servo 25 maintains an optimum length loop within column 13, in accordance with the direction of capstan 10.

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