Variable speed refrigeration compressor

A refrigerant compression system comprising;

• compressor means;
• two phase motor means drivingly connected to said compressor means, said motor means including first and second phase stator windings;
• supply means for supplying non-two phase alternating current;
• conversion means for converting said non-two phase alternating current to two phase alternating current;
• and
• alternate power supply means operative to connect said two phase motor means directly to said supply means in response to a failure of said conversion means whereby said motor means may continue to drive said compressor means,
• said alternate power supply means including switch means and capacitor means, said switch means being operative to connect said first and second phase windings in parallel relationship with said supply means and to connect said capacitor in series with one of said first and second phase windings.

An improved two phase motor providing reduced harmonic distortion and having a stator assembly and a rotor rotatably supported within said stator assembly, said stator assembly being operative to generate a rotating magnetic field for rotatably driving said rotor, said stator assembly comprising a plurality of laminations and first and second phase windings disposed within slots provided in said laminations, each of said first and second phase windings including at least two poles with each pole being defined by a plurality of coils each consisting of a predetermined number of turns of an electrical conductor and spanning a predetermined number of said slots, the improvement wherein the number of coils per pole, the number of slots spanned by each pole and by respective coils defining each of said poles and the number of said turns are selected such that ##EQU4## wherein A.sub.x =the number of conductor turns for each coil x

• B.sub.x =the number of slots spannd by each coil x
• C=the number of slots for each pole
• D=the total number of turns per pole
• and N is equal to the harmonic level to be eliminated.

A refrigerant compression system comprising:

• compressor means;
• two phase motor means drivingly connected to said compressor means;
• input means for inputting a non two phase alternating supply current;
• conversion means for converting said supply current to two phase alternating current;
• condition responsive control means for controlling the frequency of said two phase alternating current in response to a condition;
• means for conducting said two phase controlled frequency alternating current to said motor means for driving said motor means and hence said compressor means at a speed proportional to said frequency, whereby the output of said compressor means is controlled in response to said condition;
• and
• alternate power supply means connected between said non two phase alternating supply current and said two phase motor for interconnecting the stator windings of said two phase motor so as to enable said motor to operate from said non-two phase alternating supply current and connecting said two phase motor directly to said non two phase alternating supply current in the event of a failure of said conversion means.

A refrigerant compression system comprising:

• compressor means;
• two phase motor means drivingly connected to said compressor means;
• input means for inputting a single phase alternating supply current;
• conversion means for converting said supply current to two phase alternating current;
• condition responsive control means for controlling the frequency of said two phase alternating current in response to a condition;
• means for conducting said two phase controlled frequency alternating current to said motor means for driving said motor means and hence said compressor means at a speed proportional to said frequency, whereby the output of said compressor means is controlled in response to said condition;
• and
• alternate power supply means connected between said single phase alternating supply current and said two phase motor for connecting said two phase motor directly to said single phase alternating supply current in the event of failure of said conversion means;
• said input means including switch means for connecting said single phase power to said conversion means and said alternate power supply is electrically interlocked with said switch means whereby actuation of said alternate power supply will operate to open said switch means thereby disconnecting said conversion means from said single phase power source.

A refrigerant compression system comprising:

• compressor means;
• two phase motor means drivingly connected to said compressor means;
• said two phase motor including a stator assembly and a rotor rotatably supported within said stator assembly, said stator assembly being operative to generate a rotating magnetic field for rotatably driving said rotor, said stator assembly comprising a plurality of laminations and first and second phase windings disposed within slots provided in said laminations, each of said first and second phase windings including at least two poles with each pole being defined by a plurality of coils each consisting of a predetermined number of turns of an electrical conductor and spanning a predetermined number of said slots, the improvement wherein the number of coils per pole, the number of slots spanned by each pole and by respective coils defining each of said poles and the number of said turns are such that ##EQU5## wherein A.sub.x =the number of conductor turns for each coil x
• B.sub.x =the number of slots spanned by each coil x
• C=the number of slots for each pole
• D=the total number of turns per pole
• and n is equal to the harmonic level to be eliminated;
• input means for inputting a non two phase alternating supply current;
• conversion means for converting said supply current to two phase alternating current;
• condition responsive control means for controlling the frequency of said two phase alternating current in response to a condition;
• and
• means for conducting said two phase controlled frequency alternating current to said motor means for driving said motor means and hence said compressor means at a speed proportional to said frequency, whereby the output of said compressor means is controlled in response to said condition.

A refrigerant compression system comprising:

• compressor means;
• two phase motor means drivingly connected to said compressor means and including first and second phase stator windings;
• supply means for suppying non-two phase alternating current;
• conversion means for converting said non-two phase alternating current to two phase alternating current;
• adjustable control means connected to said conversion means for controlling the frequency of said two phase alternating current, whereby the frequency of said two phase alternating current may be adjusted in accordance with operating conditions so as to vary the speed of said motor means and hence said compressor means;
• filter means connected between said conversion means and said motor means for shaping the waveform of each phase of said two phase alternating current;
• protection means associated with said motor means including first current responsive means connected in series with said first stator winding, second current responsive means connected in series with said second stator winding and circuit interrupting means electrically connected to each of said first and second current responsive means, said first and second current responsive means being operative to actuate said circuit interrupting means in response to a sensed adverse condition whereby current flow to said motor means is interrupted;
• and
• alternate connecting means for connecting said two phase motor means directly to said supply means in response to a failure of said conversion means whereby said motor means may continue to drive said compressor means.