Control device for an object such as a rotor in a prime mover or the like

Claim 2

A fail-safe control device for controlling a variable associated with the operation of an object device comprising: a first control system for generating a first control signal which is a function of the value of said variable associated with said operation of said object device; a second control system for generating a second control signal which is a function of deviation of said variable associated with said operation of said object device; a selecting means coupled to said control systems for selecting one of said first or second control signals which has a value that would cause said controlled variable to change in a safeoperation direction, and for passing said selected signal in preference; a change ratio detecting means for locking said selecting means so as to cause it always to pass the other of said control signals when the rate of change of a signal corresponding to the output of said selecting means exceeds a predetermined value; and means for controlling said object device in accordance with the control signal passed by said selecting means.

Claim 3

Apparatus according to claim 1 comprising means for terminating operation of said object device when said change ratio detecting means is actuated continuously for longer than a predetermined time.

Claim 4

Apparatus according to claim 1 wherein said change ratio detecting means is directly responsive to said control signals.

Claim 5

Apparatus according to claim 1 wherein said change ratio detecting means further causes said selecting means to pass said one control signal in preference where the change ratio of a signal corresponding to said another control signal exceeds a predetermined value.

Claim 6

Apparatus according to claim 4 comprising means for terminating the operation of the object device when the change ratio of said signals corresponding to both of said first and second control signals exceed said predetermined values.

Claim 7

Apparatus according to claim 1 further comprising means for detecting deviations between said first and second control signals; and means for indicating that said deviation exceeds a predetermined limit.

Claim 8

Apparatus according to claim 6 further comprising means for detecting deviations between said first and second control signals; and means for indicating that said deviation exceeds a predetermined limit.

Claim 9

Apparatus according to claim 1 comprising means for adding a signal having a predetermined value to one of said control signals to cause said selecting means to pass the other of said control signals during normal operation.

Claim 10

A fail-safe control device for controlling the velocity of a rotating member, such as a rotating section of a prime mover, comprising: means for detecting the velocity of said rotating member; first and second control systems for generating first and second electrical control outputs which are a function of the velocity of the rotating member, said first electrical control output having a value to control the operation of the rotating member at a velocity slightly lower by a specified value than that provided by the second electrical control output; selecting means for selecting either the first or second control output which will control the velocity of the rotating member to a lower velocity, and passing said selected output in preference; change ratio detecting means for locking said selecting means so as to cause it always to pass the other control output in preference, when the rate of change of a signal corresponding to one of said control outputs exceeds a predetermIned value; and means controlling the velocity of the rotating member in accordance with the control output preferentially passed by said selecting means.

Claim 11

A fail-safe control device for controlling the velocity of a rotating member, such as a rotating section of a prime mover, comprising: means for detecting the velocity of said rotating member; first and second control systems for generating first and second electrical control outputs which are a function of the velocity of the rotating member, said first electrical control output having a value to control the operation of the rotating member at a velocity slightly lower by a specified value than that provided by the second electrical control output; selecting means for selecting either the first or second control output which will control the velocity of the rotating member to a lower velocity, and passing said selected output in preference; change ratio detecting means for locking said selecting means so as to cause it always to pass the other control output in preference, when the rate of change of a signal corresponding to one of said control outputs exceeds a predetermIned value; and means controlling the velocity of the rotating member in accordance with the control output preferentially passed by said selecting means.

Claim 12

Apparatus according to claim 9 comprising means for terminating the operation of said prime mover when said change ratio detecting means is actuated continuously for longer than a predetermined time.

Claim 13

Apparatus according to claim 9 comprising means for stopping the operation of said prime mover when signals corresponding to said first and second control outputs both have greater rates of change than said predetermined value.

Claim 14

Apparatus according to claim 9 further comprising means for detecting deviations between said first and second control outputs; and means for indicating when said deviation exceeds a predetermined limit.

Claim 15

Apparatus according to claim 10 wherein said change ratio detecting means is responsive directly to said first and second control outputs.

Claim 16

Apparatus according to claim 9 wherein said first control system includes bias means for adding a signal having a predetermined value to signals corresponding to the velocity of the rotating member to cause said first electrical control output to have said value to control the operation of the rotating member at said slightly lower velocity.