Refrigeration system prv motor control system

Claim 2

In a refrigeration system of the type whose cooling capacity, is, at least in part, governed by the setting of throttling means, the improvement, comprising: means for producing an electrical control signal that varies one of its characteristics from a norm to indicate thereby a desired change in cooling capacity of the refrigeration system; means coupled to receive the control signal and responsive thereto to produce a d.c. pulse train output of essentially one frequency but varying pulse width as a function of the variation in characteristics of the control system; an electric motor coupled to said pulse producing means and to the throttling means for adjusting the setting of the throttling means, said motor having windings that are energized in response to the pulse train output of said pulse producing means, and wherein a source of override signals is provided; logic means are coupled to said pulse producing means and to said override signals for preventing adjustment of the setting of the throttling means in response to the control signal in response to the override signals.

Claim 3

The improvement in temperature regulator control system for refrigeration equipment of the type having a capacity control analog signal source, and having its capacity governed by an a.c. electric motor which motor is of the type that can be operated from a source of fixed frequency a.c. power in either clockwise or counterclockwise direction, comprising in combination: first and second means for producing pulses of essentially one frequency but of variable width, said first and second means respectively producing pulses whenever the capacity control signal exceeds a first pre-set value or is below a second pre-set value, said first and second means then producing pulses whose width is a function of the difference between the control signal value and their respective pre-set values, the pulses when produced by said first and second means being at a frequency which is small compared to the fixed frequency of the a.c. power; said first and second pre-set values differing from each other so as to establish a deadband wherein the control signal may vary without resulting in pulses being produced by either said first or second means; means responsive to the pulses of first means for coupling the a.c. power to the a.c. electric motor so as to cause it to rotate in the clockwise direction for the duration of the first means pulses; and means responsive to the second means for coupling the a.c. power to the a.c. electric motor so as to cause it to rotate in the counterclockwise direction for the duration of the second means pulses.

Claim 4

The improvement in temperature regulator control system for refrigeration equipment of the type having a capacity control analog signal source, and having its capacity governed by an a.c. electric motor which motor is of the type that can be operated from a source of fixed frequency a.c. power in either clockwise or counterclockwise direction, comprising in combination: first and second means for producing pulses of essentially one frequency but of variable width, said first and second means respectively producing pulses whenever the capacity control signal exceeds a first pre-set value or is below a second pre-set value, said first and second means then producing pulses whose width is a function of the difference between the control signal value and their respective pre-set values, the pulses when produced by said first and second means being at a frequency which is small compared to the fixed frequency of the a.c. power; said first and second pre-set values differing from each other so as to establish a deadband wherein the control signal may vary without resulting in pulses being produced by either said first or second means; means responsive to the pulses of first means for coupling the a.c. power to the a.c. electric motor so as to cause it to rotate in the clockwise direction for the duration of the first means pulses; and means responsive to the second means for coupling the a.c. power to the a.c. electric motor so as to cause it to rotate in the counterclockwise direction for the duration of the second means pulses.

Claim 5

The invention of claim 2 wherein: the frequency of pulses when produced by said first and second means is two orders of magnitude below the fixed frequency of the a.c. power source; said analog signal source produces a d.c. level signal whose amplitude variation from a norm level is indicative of the desired change in cooling; said first means for producing a pulse train includes a sawtooth waveform generator for producing a sawtooth output of the small frequency and a first comparator coupled thereto and to receive the control signal, said first comparator producing pulses whenever the amplitudes of the control signal and the sawtooth signal reach and exceed a certain relationship.

Claim 6

The invention of claim 3 wherein: said analog signal direction of change, above and below the norm, is indicative of the desired direction of change of decrease and increase of the system cooling capacity; and said second pulse producing means includes a second comparator coupled to said sawtooth generator and to receive said control signal, said second comparator producing pulses whenever the amplitude of the control signal and its received sawtooth signal reach and exceed a different certain relationship.