Electronic control for an automatic washing machine with a reversing PSC motor

• US 5,237,256 A
• Filed: 08/11/1989
• Issued: 08/17/1993
• Est. Priority Date: 08/11/1989
• Status: Expired due to Fees

• Current Assignee: Whirlpool Corporation
• Original Assignee: Whirlpool Corporation
• Inventors: Bashark, Larry T.
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Cabeca, John W.
• Application Number:
  US07/392,473
• Time in Patent Office: 1,467 Days
• Field of Search: 318/257, 318/817, 318/455, 318/795, 318/772, 318/729, 318/775, 318/778, 318/779, 318/796, 318/806, 318/809, 318/812, 318/822, 318/798, 318/280, 318/727, 318/681, 318/430 , 318/434, 160/22 A, 68/12 R, 68/133, 68/134
• US Class Current: 318/817
• CPC Class Codes: D06F 2103/38 Time, e.g. duration
• CPC Class Codes: D06F 2103/46 of the motor driving the drum
• CPC Class Codes: D06F 2105/46 Drum speed; Actuation of motors, e.g. starting or interrupting
• CPC Class Codes: D06F 33/30 Control of washing machines characterised by the purpose or target of the control controlling processes of washer-dryers D06F33/50
• CPC Class Codes: D06F 34/08 Control circuits or arrangements thereof
• CPC Class Codes: D06F 37/304 Arrangements or adaptations of electric motors
• CPC Class Codes: H02P 25/04 Single phase motors, e.g. capacitor motors

Abstract

A control for an automatic washing machine with a reversing permanent split capacitor (PSC) drive motor. Separate ferrite core sensors surround each of two PSC motor windings. A sense winding is threaded through both sensors. A brief output voltage is generated whenever the alternating current in either PSC motor winding passes through a zero-crossing and when the sense winding is wound with proper mutual polarity, an output voltage is generated in response to zero-crossings of a brief, residual alternating current which flows in both PSC motor windings and the capacitor when the rotating PSC motor is cycled OFF. The circuitry, in combination with the sensors, samples the leading or lagging phase angle of the PSC motor auxiliary or main winding, respectively, at a sample rate of two-times the line frequency when the PSC motor is ON. The raw PSC motor phase data is used in microcomputer programs to compute motor start time or load torque dither. This computed information and the PSC motor braking data, is used by other software programs to automatically control various functions of the washing machine such as the fill water level and agitator stroke angle; to control events in an operational sequence such as the duration of the agitation and spin operations; and to provide diagnostic information such as spin off-balance detection.

Claims

1. An apparatus for monitoring the start time of a permanent split capacitor motor having first and second motor windings, said motor being powered by a supply having an alternating line voltage, said apparatus comprising:

means for sensing zero crossings of alternating current in a motor winding when said motor is on to provide a representation thereof;

means for detecting zero crossings of said line voltage to provide a representation thereof;

means responsive to said current zero crossing representation and said voltage zero crossing representation for determining a motor phase angle to provide a representation thereof; and

means responsive to said motor phase angle representation for detecting a characteristic increase in said motor phase angle representing the time at which said motor reaches operating speed;

said current sensing means includes a first transformer having a primary winding including at least one turn of said first motor winding, and a second transformer having a primary winding including at least one turn of said second motor winding and a sense winding extending through said first and second transformers wherein the polarity of said sense winding is such that the signals from each transformer are additive when said motor is cycled off.

2. An apparatus for monitoring the start time of a permanent split capacitor motor as recited in claim 1 wherein said transformers are core transformers.

3. An apparatus for monitoring the start time of a permanent split capacitor motor as recited in claim 1 wherein said transformers are nickel tape-wound core transformers.

4. An apparatus for monitoring the amount of dither in a permanent split capacitor motor having first and second motor windings, said motor being powered by a power supply having an alternating line voltage, said apparatus comprising:

means for detecting zero crossings of alternating current in a motor winding when said motor is on to provide a representation of said current zero crossings;

means for detecting zero crossings of said supply voltage to provide a representation thereof;

means responsive to said zero crossing representations for determining a motor phase angle, said means providing a representation thereof; and

means responsive to said motor phase angle representation for detecting the amount of dither in said motor and providing a representation thereof.

5. An apparatus for monitoring the start time of a permanent split capacitor motor as recited in claim 4 wherein said current zero crossing sensing means includes a ferrite core transformer having a primary winding including at least one turn of a motor winding and a secondary winding at which said current zero crossing signal is generated.

6. An apparatus for monitoring the start time of a permanent split capacitor motor as recited in claim 4 wherein said current sensing means includes a first transformer having a primary winding including at least one turn of said first motor winding and a second transformer having a primary winding including at least one turn of said second motor winding and a sense winding extending through said first and second transformers wherein the polarity of said sense winding is such that the signals from each transformer are additive when said motor is cycled off.

7. An apparatus for monitoring the start time of a permanent split capacitor motor as recited in claim 4 wherein said current sensing means includes a nickel tape-wound core transformer having a primary winding including at least one turn of a motor winding and a secondary winding at which said current zero crossing signal is generated.

8. An apparatus for monitoring the start time of a permanent split capacitor motor as recited in claim 4 wherein said current zero crossing sensing means senses zero crossings of alternating current in each of said motor windings to provide a signal representative thereof.

9. An apparatus for monitoring the start time of a permanent split capacitor motor as recited in claim 4 wherein said motor phase angle represents the main winding phase angle when said motor is on.

10. An apparatus for monitoring the amount of dither in a permanent split capacitor motor according to claim 4 further comprising means responsive to said dither representation for controlling operation of said motor.

11. An apparatus for monitoring the amount of dither in a permanent split capacitor motor according to claim 10 wherein said means responsive to said dither representation for controlling operation of said motor further comprises:

means for summing the differences between a predetermined number of motor phase angles determined during half cycles of the same polarity to provide a representation of said sum;

means for comparing said sum representation to a reference value at the end of said predetermined number of phase angles; and

means for stopping said motor if said sum exceeds said reference value.

12. An apparatus for monitoring the start time of a permanent split capacitor motor as recited in claim 11 wherein said current sensing means includes a first transformer having a primary winding including at least one turn of said first motor winding and a second transformer having a primary winding including at least one turn of said second motor winding and a sense winding extending through said first and second transformers wherein the polarity of said sense winding is such that the signals from each transformer are additive when said motor is cycled off.

13. An apparatus for monitoring the amount of dither in a permanent split capacitor motor according to claim 10 further comprising means responsive to said dither representation, said means halting operation of said motor if the amount dither exceeds a predetermined level.

14. A permanent split capacitor motor adapted for phase angle monitoring comprising:

a first motor winding;

a first transformer having a primary winding including at least one turn of said first motor winding;

a second motor winding;

a second transformer having a primary winding including at least one turn of said second motor winding; and

a sense winding extending through said first and second transformers, said sense winding having a predetermined polarity such that signals from each transformer are additive.

15. A permanent split capacitor motor adapted for phase angle monitoring as recited in claim 14 wherein said transformers are core transformers.

16. A permanent split capacitor motor adapted for phase angle monitoring as recited in claim 14 wherein said transformers are nickel tape-wound core transformers.

17. In an apparatus having a permanent split capacitor motor with first and second motor windings, said motor being powered by a supply having an alternating line voltage, an apparatus for monitoring the start up time of said motor comprising:

means for sensing zero crossings of alternating currents in said first motor winding and said second motor winding when said motor is on to provide a signal representative thereof;

means for detecting zero crossings of said line voltage to provide a signal representative thereof;

means responsive to said current zero crossing signal and said voltage zero crossing signal for determining a motor phase angle representation thereof;

means responsive to said motor phase angle representation for controlling an operation of said apparatus; and

wherein said current sensing means includes a first transformer having a primary winding including at least one turn of said first motor winding, and a second winding at which said current zero crossing signal is generated, and a second transformer having a primary winding including at least one turn of said second motor winding, and a secondary winding at which said current zero crossing signal is generated.

18. In an apparatus having a permanent split capacitor motor with first and second motor windings, said motor being powered by a supply having an alternating line voltage, an apparatus for monitoring the start up time of said motor comprising:

means for sensing zero crossings of alternating currents in said first motor winding and said second motor winding when said motor is on to provide a signal representative thereof;

means for detecting zero crossings of said line voltage to provide a signal representative thereof;

means responsive to said current zero crossing signal and said voltage zero crossing signal for determining a motor phase angle representation thereof;

means responsive to said motor phase angle representation for controlling an operation of said apparatus; and

wherein said current sensing means includes a first transformer having a primary winding including at least one turn of said first motor winding and a second transformer having a primary winding including at least one turn of said second motor winding and a sense winding extending through said first and second transformers wherein the polarity of said sense winding is such that the signals from each transformer are additive when said motor is cycled off.

19. In an automatic washing machine having a permanent split capacitor motor with first and second motor windings, said motor being powered by a supply having an alternating line voltage, an apparatus for monitoring the start up time of said motor comprising:

means for sensing zero crossings of alternating currents in said first motor winding and said second motor winding when said motor is on to provide a signal representative thereof;

means for detecting zero crossings of said line voltage to provide a signal representative thereof;

means responsive to said current zero crossing signal and said voltage zero crossing signal for determining a motor phase angle representation thereof;

means responsive to said motor phase angle representation for detecting a characteristic increase in said phase angle representing the time at which said motor reaches operating speed to provide a representation thereof;

means responsive to said motor start time representation for controlling an operation of said washing machine; and

wherein said current sensing means includes a first transformer having a primary winding including at least one turn of said first motor winding, and a secondary winding at which said current zero crossing signal is generated, and a second transformer having a primary winding including at least one turn of said second motor winding, and a secondary winding at which said current zero crossing signal is generated.

20. In an automatic washing machine having a permanent split capacitor motor with first and second motor windings, said motor being powered by a supply having an alternating line voltage, an apparatus for monitoring the start up time of said motor comprising:

means for sensing zero crossings of alternating currents in said first motor winding and said second motor winding when said motor is on to provide a signal representative thereof;

means for detecting zero crossings of said line voltage to provide a signal representative thereof;

means responsive to said current zero crossing signal and said voltage zero crossing signal for determining a motor phase angle representation thereof;

means responsive to said motor phase angle representation for detecting a characteristic increase in said phase angle representing the time at which said motor reaches operating speed to provide a representation thereof;

means responsive to said motor start time representation for controlling an operation of said washing machine; and

wherein said current sensing means includes a first transformer having a primary winding including at least one turn of said first motor winding and a second transformer having a primary winding including at least one turn of said second motor winding and a sense winding extending through said transformers wherein the polarity of said sense winding is such that the signals from each transformer are additive when said motor is cycled off.

21. In an automatic washing machine having a permanent split capacitor motor with first and second motor windings, said motor being powered by a supply having an alternating line voltage, an apparatus for monitoring the start up time of said motor comprising:

means for sensing zero crossings of alternating currents in said first motor winding and said second motor winding when said motor is on to provide a signal representative thereof;

means for detecting zero crossings of said line voltage to provide a signal representative thereof;

means responsive to said current zero crossing signal and said voltage zero crossing signal for determining a motor phase angle representation thereof;

means responsive to said motor phase angle representation for detecting a characteristic increase in said phase angle representing the time at which said motor reaches operating speed to provide a representation thereof;

means responsive to said motor start time representation for controlling an operation of said washing machine; and

wherein said control means includes means responsive to said motor phase angle representation and determining the amount of dither in said motor during a spin operation to provide a representation thereof.

22. An apparatus for monitoring the start up time of a motor as recited in claim 21 wherein said control means includes means for monitoring said motor dither representation over a predetermined period of time to detect an off balance condition in said washing machine.

23. An apparatus for monitoring the start up time of a motor as recited in claim 22 wherein said control means includes means for comparing said motor dither representation to a reference value at the end of said period of time;

and means for stopping said spin operation if said motor dither representation exceeds said reference value.

24. In an automatic washing machine having a permanent split capacitor motor with first and second motor windings, said motor being powered by a supply having an alternating line voltage, the improvement comprising:

means responsive to said line voltage and the current flowing through said first winding and said second winding of said motor for determining a motor phase angle to provide a representation thereof;

means responsive to said motor phase angle representation for determining the start time of said motor to provide a representation thereof;

means responsive to said motor start time representation for controlling an operation of said washing machine; and

wherein said control means includes means responsive to said motor phase angle representation to determine the amount of dither in said motor during a spin operation to provide a representation thereof.

25. The improvement recited in claim 24 wherein said control means includes means for monitoring said motor dither representations over a predetermined period of time to detect an off balance condition in said washing machine.

26. The improvement recited in claim 25 wherein said control means includes means for comparing said motor dither representation to a reference value at the end of said period of time;

and means for stopping said spin operation if said motor dither representation exceeds said reference value.

27. An automatic washing machine powered by an alternating current power supply, said automatic washing machine comprising:

a rotatable laundering vessel;

a permanent split capacitor motor coupled to said rotatable laundering vessel to selectively drive said rotatable laundering vessel;

control means coupled to said motor for selectively applying power to said motor from said power supply;

time measuring means measuring the time required for the motor to reach full operational speed following the application of power, said time measuring means including means for detecting zero crossings of alternating current in a first winding of said motor and a second winding of said motor to provide a signal representation thereof;

spin control means responsive to said measured time for controlling the spin operation of said rotatable laundering vessel of said washing machine;

means for detecting zero crossings of said supply voltage to provide a representation thereof;

means responsive to said zero crossing representations for determining a motor phase angle to provide a representation thereof;

means responsive to said motor phase angle representation for detecting a characteristic phase angle increase therein representation of the time at which said motor reaches operating speed and providing said start-up time representation; and

wherein said control means includes means responsive to said motor phase angle representation to determine the amount of dither in said motor during a spin operation to provide a representation thereof.

28. The machine of claim 27 wherein said control means includes means for monitoring said motor dither representations over a predetermined period of time to detect an off balance condition in said washing machine.

29. The machine of claim 28 wherein said control means includes means for comparing said motor dither representation to a reference value at the end of said period of time;

and means for stopping said spin operation if said motor dither representation exceeds said reference value.

30. A method of determining the time at which a permanent split capacitor motor operating under load attains full operating speed, said motor having first and second motor windings and being powered by a supply having an alternating line voltage, said method comprising the steps of:

sensing the zero crossings of alternating currents in said first motor winding and said second motor winding when said motor is on;

providing a representation of said current zero crossings;

sensing zero crossings of said line voltage;

providing a representation of said voltage zero crossings;

determining a motor phase angle from said voltage and current zero crossing representations;

providing a representation of said motor phase angle;

detecting a characteristic increase in said motor phase angle representation representing the time at which said motor has attained full operating speed;

wherein the motor phase angle detecting step further comprises the steps of;

monitoring the motor phase angle representation to determine the amount of dither in said motor;

monitoring the dither representation over a predetermined period of time to detect an off-balance condition in said washing machine;

comparing the motor dither to a reference value at the end of said predetermined period of time; and

stopping the spin operation if said motor dither exceeds said reference value.

31. The method of claim 30 wherein said motor phase angle monitoring step further comprises the steps of:

summing the differences between a predetermined number of motor phase angles determined during half cycles of the same polarity to provide a representation of said sum;

comparing said sum representation to a reference value at the end of said predetermined number of phase angles;

stopping said motor if said sum exceeds said reference value.

32. A method of detecting dither in a permanent split capacitor motor comprising the steps of:

sensing the zero crossings of alternating currents in a motor winding when said motor is on;

providing a representation of said current zero crossings;

sensing zero crossings of said line voltage;

providing a representation of said voltage zero crossings;

determining a motor phase angle from said voltage and current zero crossing representations;

providing a representation of said motor phase angle; and

detecting the amount of dither in said motor from said motor phase angle representation.

33. The method of claim 32 further comprising the step of halting the operation of said motor if the amount of dither detected exceeds a predetermined maximum level.

34. The method of claim 32 wherein said step of detecting the amount of dither comprises the steps of:

summing the differences between a predetermined number of motor phase angles determined during half cycles of the same polarity;

providing a representation of said sum;

comparing said sum representation to a reference value at the end of said predetermined number of motor phase angles; and

stopping said motor if said sum exceeds a reference value.

35. An automatic washing machine powered by a power supply having an alternating line voltage, said automatic washing machine comprising:

a vertically rotatable laundering vessel;

a permanent split capacitor motor having a first and a second winding, said motor being coupled to said rotatable laundering vessel to selectively drive said rotatable laundering vessel;

control means coupled to said motor for selectively applying power to said motor from said power supply;

means coupled to said motor for selectively starting said motor;

means for detecting zero crossings of alternating current in said first motor winding and said second motor winding to proved a representation of said current zero crossings;

means for detecting zero crossings of said supply voltage to provide a representation thereof, said means comprising a transformer having a primary winding including at least one turn of a motor winding at which said zero crossing signal is generated;

means responsive to said zero crossing representations for determining the motor phase angle to provide a representation thereof;

means responsive to said motor phase angle representation for detecting a characteristic phase angle increase therein representative of the time at which said motor reaches operating speed and providing a representation of said start up time;

means for controlling the direction of a spin operation of said laundering vessel in response to said start up time representation such that the duration of said spin operation is increased when said start up time is increased;

wherein said control means further comprises;

means responsive to said motor phase angle representation to determine the amount of dither in said motor;

means for monitoring said dither representation over a predetermined period of time to detect an off-balance condition in said washing machine;

means for comparing said motor dither to a reference value at the end of said predetermined period of time; and

means for stopping said spin operation if said motor dither exceeds said reference value.

36. The apparatus of claim 35 wherein said means responsive to said phase angle to determine the amount of dither further comprises:

means for summing the differences between a predetermined number of motor phase angles determined during half cycles of the same polarity to provide a representation of said sum;

means for comparing said sum representation to a reference value at the end of said predetermined number of phase angles; and

means for stopping said motor if said sum exceeds said reference value.

37. An automatic washing machine powered by a power supply having an alternating line voltage, said automatic washing machine comprising:

a vertically rotatable laundering vessel;

a permanent split capacitor motor having a first and a second winding, said motor being coupled to said rotatable laundering vessel to selectively drive said rotatable laundering vessel;

control means coupled to said motor for selectively applying power to said motor from said power supply;

means for detecting zero crossings of alternating current in a motor winding when said motor is on to provide a representation of said current zero crossings;

means for detecting zero crossings of said supply voltage to provide a representation thereof;

means responsive to said zero crossing representations for determining a motor phase angle to provide a representation thereof;

means responsive to said motor phase angle representation to determine the amount of dither in said motor;

means for monitoring said dither representation over a predetermined period of time to detect an off-balance condition in said washing machine;

means for comparing said motor dither to a reference value at the end of said predetermined period of time; and

means for stopping said spin operation if said motor dither exceeds said reference value.

38. The apparatus of claim 37 wherein said means responsive to said phase angle to determine the amount of dither further comprises:

means for summing the differences between a predetermined number of motor phase angles determined during half cycles of the same polarity to provide a representation of said sum;

means for comparing said sum representation to a reference value at the end of said predetermined number of phase angles; and

means for stopping said motor if said sum exceeds said reference value.

39. An apparatus for monitoring the start time of a permanent split capacitor motor as recited in claim 37 wherein said current sensing means includes a first transformer having a primary winding including at least one turn of said first motor winding and a second transformer having a primary winding including at least one turn of said second motor winding and a sense winding extending through said first and second transformers wherein the polarity of said sense winding is such that the signals from each transformer are additive when said motor is cycled off.

40. An apparatus for monitoring the start time of a permanent split capacitor motor as recited in claim 37 wherein said current sensing means includes a nickel tape-wound core transformer having a primary winding including at least one turn of a motor winding and a secondary winding at which said current zero crossing signal is generated.

41. An automatic washing machine driven by a permanent split capacitor motor supplied with an alternating voltage and alternating current, said motor having a first motor winding and a second motor winding, said apparatus comprising:

a voltage detector circuit for generating a series of first pulses, each having a duration in accordance with the amplitude of a voltage supplied to said motor;

current sensing means for generating a first signal upon each occurrence of a current polarity change in said first motor winding, and a second signal upon each occurrence of a current polarity change in said second motor winding;

means for generating a series of second pulses each having a duration in accordance with the time base of said signals generated by said current sensing means;

processing means that utilize said first pulses and said second pulses to calculate a lagging motor phase angle representation of a time lag between said alternating voltage and said alternating current;

operating means for operating said automatic washing machine pursuant to a predetermined set of instructions dependent upon said motor phase angle representation;

means to determine an agitator stroke angle of an agitator within said automatic washing machine; and

wherein said current sensing means includes a first transformer having a primary winding including at least one turn of said first motor winding, and a secondary winding at which said first signal is generated, and a second transformer having a primary winding including at least one turn of said second motor winding, and a secondary winding at which said second signal is generated.

42. An automatic washing machine driven by a permanent split capacitor motor supplied with an alternating voltage and alternating current, said motor having a first motor winding and a second motor winding, said apparatus comprising:

a voltage detector circuit for generating a series of first pulses, each having a duration in accordance with the amplitude of a voltage supplied to said motor;

current sensing means for generating a first signal upon each occurrence of a current polarity change in said first motor winding, and a second signal upon each occurrence of a current polarity change in said second motor winding;

means for generating a series of second pulses each having a duration in accordance with the time base of said signals generated by said current sensing means;

processing means that utilize said first pulses and said second pulses to calculate a lagging motor phase angle representation of a time lag between said alternating voltage and said alternating current;

operating means for operating said automatic washing machine pursuant to a predetermined set of instructions dependent upon said motor phase angle representation;

means to determine an agitator stroke angle of an agitator within said automatic washing machine; and

wherein said operating means includes;

means for determining the sum of two consecutive lagging motor phase angle representations;

means for storing the minimum sum of two consecutive phase angle representations;

means for comparing the sum of two consecutive lagging motor phase angle representations to said minimum sum to determine the time at which said sum is not less than said minimum sum thereby providing a motor starting time; and

means responsive to said lagging motor phase angle representations for detecting the amount of dither in said motor and providing a representation thereof.

43. An automatic washing machine driven by a permanent split capacitor motor having a first motor winding and a second motor winding, said apparatus comprising:

a voltage detector circuit for generating a series of first pulses, each having a duration in accordance with the amplitude of a voltage supplied to said motor;

a first transformer having a primary winding including at least one turn of said first motor winding and a secondary winding at which a first signal is generated, and a second transformer having a primary winding including at least one turn of said second motor winding and a secondary winding at which a second signal is generated, said secondary winding of said first transformer and said secondary winding of said second transformer being series connected and the polarities of said secondary windings being such that said signal from each secondary winding is additive when said motor is cycled off;

means for generating a series of second pulses each having a duration in accordance with the time base of said signals generated by said first and second transformers;

processing means that utilize said first pulses and said second pulses to calculate a lagging motor phase angle representation at a time lag between said alternating voltage and said alternating current;

operating means for operating said automatic washing machine pursuant to a predetermined set of instructions dependent upon said motor phase angle representation; and

means for utilizing said first signals and said second signals generated from said secondary windings of said first and second transformers to calculate an agitator stroke angle and to control the rotation of an agitator through said calculated agitator stroke angle.

44. An automatic washing machine as recited in claim 43 wherein said means for energizing and deenergizing said first and second motor windings, respectively, includes a first triac and means to trigger said first triac operated by a microcomputer and a second triac and means to trigger said second triac operated by a microcomputer.

45. An apparatus for monitoring the start time of a permanent split capacitor motor, supplied with an alternating voltage and alternating current and having a first motor winding and a second motor winding providing information for controlling the operational sequence of a device operated by said motor, said apparatus comprising:

a voltage detector circuit for generating a series of first pulses each having a duration in accordance with the amplitude of a voltage supplied to said motor;

current sensing means for generating a first signal upon each occurrence of a current polarity change in said first motor winding, and a second signal upon each occurrence of a current polarity change in said second motor winding;

means for generating a series of second pulses each having a duration in accordance with the time base of said signals generated by said current sensing means;

processing means utilizing said first pulses and said second pulses to calculate a motor phase angle representation of a time lag between said alternating voltage and said alternating current;

operating means for operating said device pursuant to a predetermined set of instructions dependent upon said motor phase angle representation; and

wherein said current sensing means includes a first nickel tape-wound core transformer having a primary winding including at least one turn of said first motor winding, and a secondary winding at which said first signal is generated, and a second nickel tape-wound core transformer having a primary winding including at least one turn of said second motor winding, and a secondary winding at which said second signal is generated.

46. In an automatic washing machine having a permanent split capacitor motor with first and second motor windings, said motor being powered by a supply having an alternating line voltage, an apparatus for monitoring the start up time of said motor comprising:

means for sensing zero crossings of alternating currents in said first motor winding and said second motor winding when said motor is on to provide a signal representative thereof;

means for detecting zero crossings of said line voltage to provide a signal representative thereof;

means responsive to said current zero crossing signal and said voltage zero crossing signal for determining a motor phase angle representation thereof;

means responsive to said motor phase angle representation for detecting a characteristic increase in said phase angle representing the time at which said motor reaches operating speed to provide a representation thereof;

means responsive to said motor start time representation for controlling an operation of said washing machine;

including means actuable by a user for selecting a cycle to provide a representation of said cycle selection wherein said motor is coupled to a spin basket for driving said basket to spin and said control means controls the duration of said spin in response to said motor start time representation and said cycle selection representation;

wherein said washing machine has a delicate cycle and a regular cycle and said control means controls said spin duration such that for a given load said spin duration is longer for a regular cycle than for a delicate cycle; and

wherein said washing machine has a permanent press cycle and a normal cycle and said control means controls said spin duration such that for a given load said spin duration is longer for a normal cycle than for a permanent press cycle.