Speed control device

Claim 1

A speed governing device adopted to control the rate of a rotating power plant comprising: control means connected to said power plant for controlling the rotational rate thereof; a rate sensor connected to the output of said power plant for providing a cyclic feedback signal proportional to the rotational rate of said power plant; a resonant circuit connected to receive said cyclic feedback signal for producing an output signal of a first polarity when said cyclic signal is above a predetermined frequency and of a second polarity when said cyclic signal below said predetermined frequency; first amplifying means connected to receive said output signal from said resonant circuit including first biasing means, said first amplifying means in combination with said biasing being rendered responsive to said first polarity of said output signal for producing a first control signal indicative thereof; second amplifying means connected to receive said output signal from said resonant circuit including second biasing means, said second amplifying and biasing means being operative in combination to be rendered responsive to said second polarity of said output signal for producing a second control signal indicative thereof; and a servo motor connected to receive said first and second control signals for producing control inputs to said control means according to the presence of said first or second control signal, said first and second amplifying means each include a PNP first transistor forming a first preamplifier stage and an NPN transistor forming a second preamplifier stage in circuit with said first preamplifier stage.