Automatic transfer control device and frequency monitor

Apparatus for monitoring the frequency of an alternating current power source, comprising:

• an oscillator;
• a counter connected to said oscillator for generating binary representations of the number of output pulses of said oscillator;
• means responsive to said power source for activating said oscillator for a predetermined number of cycles of said power source, whereby said counter accumulates a number of pulses inversely proportional to frequency of said power source;
• memory means for storing a binary representation of a pulse count corresponding to a frequency limit value;
• means connected to said counter and said memory means for comparing the binary representation accumulated by said counter with said binary representation stored in said memory means;
• and
• means for generating an alarm signal whenever the binary representation of said counter falls outside of said limit value binary representation.

Apparatus for monitoring the frequency of an alternating current power source, comprising:

• means for producing a test value proportional to time;
• synchronizing means connected to said test value producing means and responsive to the output of said power source for operating said test value producing means for a predetermined number of cycles of said power source;
• memory means for storing a reference value proportional to permissible frequency limits;
• comparator means for comparing said test value and said reference value, said comparator means producing an alarm signal when said test value is outside of the limits defined by said reference value;
• means connected to the power source and said memory means for momentarily supplying operating energy to said memory;
• and
• means for latching the output of said memory means and for supplying the output of said memory means to said comparator means.

Apparatus for monitoring the frequency of an alternating current power source, comprising:

• means for producing a test value proportional to time;
• synchronizing means connected to said test value producing means and responsive to the output of said power source for operating said test value producing means for a predetermined number of cycles of said power source output;
• memory means comprising a plurality of data value storage locations for storing a plurality of reference values proportional to permissible frequency limits each corresponding to a specific function to be performed by said apparatus;
• comparator means for comparing said test value and one of said reference values;
• and
• means to selectively present one of said references values to said comparator means;
• said comparator means producing an alarm signal when said test value is outside of the limits defined by said reference value.