US3764822A - Arrangement for driving the drum of a washing machine - Google Patents

Arrangement for driving the drum of a washing machine Download PDF

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US3764822A
US3764822A US3764822DA US3764822A US 3764822 A US3764822 A US 3764822A US 3764822D A US3764822D A US 3764822DA US 3764822 A US3764822 A US 3764822A
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United States
Prior art keywords
rectifier
control
motor
supply voltage
control signal
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English (en)
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W Ebbinge
Ruiter C De
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US Philips Corp
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US Philips Corp
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
    • H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
    • H02P25/10—Commutator motors, e.g. repulsion motors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
    • H02P7/06—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current
    • H02P7/18—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power
    • H02P7/24—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices
    • H02P7/28—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices
    • H02P7/285—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only
    • H02P7/292—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only using static converters, e.g. AC to DC
    • H02P7/295—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only using static converters, e.g. AC to DC of the kind having one thyristor or the like in series with the power supply and the motor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S388/00—Electricity: motor control systems
    • Y10S388/907—Specific control circuit element or device
    • Y10S388/917—Thyristor or scr
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S388/00—Electricity: motor control systems
    • Y10S388/923—Specific feedback condition or device
    • Y10S388/934—Thermal condition

Definitions

  • This supply circuit further contains a first rectifier which is connected in series with the motor and becomes conducting at the passages through zero of the supply voltage.
  • Speed control of the motor is effected by means of a second rectifier which is of a bidirectional type and which shunts the series combination of the motor and the first rectifier and is set to the conductive condition by means of control pulses.
  • the power dissipated by the heating element may also be regulated by means of this second rectifier.
  • the invention relates to an arrangement including a self-commutating electric motor for driving the drum of a washing machine, which arrangement is provided with at least one electric heating element and has a supply circuit for the motor, which circuit includes the series combination of the heating element and a first rectifier, and a switch which is connected across the series combination of the motor and the first rectifier.
  • the exaggerated series characteristic of the motor further results in that the transition from washing speed to spinning speed is particularly smooth. During this transition the motor speed may be increased to the spinning speed before all the wash water has drained away, which, if the drum speed is appropriately chosen, may involve a very satisfactory distribution of the washing load.
  • a controlled rectifier is connected in series with the motor.
  • phase control of the supply voltage is achieved, i.e., the controlled rectifier is rendered conductive for one halfcycle of the supply voltage by the application of a triggering signal to its control electrode and remains conductive for the remainder of this half-cycle. This control of the triggering instant enables the motor current and hence the motor speed to be controlled.
  • the arrangement described hereinbefore suffers from some limitations and disadvantages. Firstly the amount of heat generated by the heating element is entirely dependent on the operating condition of the motor, because the value of the series resistor is completely determined by the desired spinning speed. This desired spinning speed also determines the back E.M.F. of the motor at the washing speed and hence the current flowing through the motor and the series resistor at a given desired power. This means that the power dissipated in the series resistor and hence the heat emission during the washing cycle are entirely determined by the desired spinning and washing speeds, which may prevent the generation of heat from reaching a desired high value during the washing cycle. Furthermore the current flowing through the series resistor depends upon the motor control, i.e., upon the triggering instant of the controlled rectifier, and hence the generation of heat will also vary with this control.
  • an additional heating element may obviously be provided.
  • this additional heating element requires the provision of an additional power switch which must be switched by the program device.
  • a second possibility of increasing the generation of heat consists in the provision of an additional switch which is capable of directly connecting the heating element to the supply voltage, as is described in the said Patent. This switch may be closed in the stationary condition of the motor so that the heating element delivers its maximum power.
  • the power delivered by the heating element is entirely dependent upon the washing rhythm, i.e., upon the durations of the times during which the drum must rotate and be stationary.
  • the drum may be required to rotate for periods of 12 seconds each with stationary intervals of 3 seconds, whereas for another washing program the drum may be required to rotate for periods of 3 seconds separated by stationary periods of 12 seconds.
  • the amounts of power dissipated by the heating element will be widely different in these cases.
  • the additional power switch will be subject to intense wear.
  • a second disadvantage of the known arrangement is the risk of radio-frequency interference owing to the phase control by means of the controlled rectifier.
  • This risk of radio-frequency interference is due to the fact that the rectifier is triggered, and hence the motor current is switched on, at an instant at which the supply voltage has reached a value different from zero, possibly even its maximum value, which gives rise to large current variations.
  • the arrangement according to the invention is characterized in that the switch consists of a second rectifier which is of a bidirectional conductivity type and has a control electrode to which a control signal may be applied which controls the conduction period of the rectifier.
  • a first advantage of the arrangement according to the invention is that the power supplied to, and dissipated by, the heating element is approximately independent of the operating condition of the motor. This is directly due to the provision of the second controlled bidirectional rectifier and to the fact that the speed of the motor is controlled by means of this rectifier. The presence of this controlled rectifier permits the use of a motor control method different from the conductionangle phase control employed in the known arrangement.
  • this supply may be terminated at any desired instant by triggering the second controlled rectifier, for this rectifier shunts the series combination of the motor and the first rectifier, so that rendering this second rectifier conductive causes the said series combination to be short-circuited with the result that no current is supplied to the motor.
  • Triggering this sec ond rectifier entails only a limited variation of the current flowing through the series resistor. Before the triggering instant this current is equal to the motor current and after the triggering instant the series resistor is directly fed with the supply voltage.
  • the second rectifier permits of ensuring that the series resistor is supplied during the other half-cycle of the supply voltage also.
  • the heating element is fed during the entire cycle of the supply voltage and hence dissipates maximum power.
  • the second rectifier is not re-triggered at the aforementioned instant, the heating element is energized during only one half-cycle of the supply voltage so that it dissipates only one half of its maximum power. Triggering this second rectifier consequently ensures, in addition to the motor control, control of the heating effected by the heating element.
  • a second advantage is that the risk of radiofrequency interference can be appreciably reduced, for the motor current may be switched on at an instant at which the voltage across the first rectifier is zero, which instant is determined by the variation of the supply voltage and the value of the back E.M.F.
  • the ensuing transient phenomena and hence the resulting radiofrequency interference will be a minimum so that the anti-interference means required may be reduced to a minimum.
  • a third advantage is that the variations of the line load are appreciably smaller than in the known arrangement.
  • the heating element is not continually switched on each time the motor is stopped, but owing to the triggering of the second rectifier it is fed during the entire cycle of the supply voltage, so that the variations in the line load are negligible.
  • a first embodiment of the arrangement according to the invention furthermore enables the direction of the motor to be electronically reversed.
  • the first rectifier element connected in series with the motor is a controlled bidirectional rectifier element. Changing the triggering instants of the first and second rectifier elements permits of reversing the direction of flow of the motor current.
  • a second embodiment of the arrangement according to the invention is characterized in that the first rectifier is a diode.
  • the use of such an uncontrolled rectifier is possible in the arrangement according to the invention because this rectifier need not be used for the speed control.
  • motors with permanentmagnet energization for example, motors with permanentmagnet energization, collector motors with series, shunt or compound energisation, motors having rotating permanent magnets, and so on.
  • FIG. 1 is a schematic circuit diagram of an embodiment of the known arrangement
  • FIGS. 2 and 3 are schematic circuit diagrams of two embodiments of the arrangement according to the invention.
  • FIG. 4 shows the waveforms of the various currents flowing in an arrangement according to the invention.
  • FIG. 5 shows, by way of example, a circuit diagram of an arrangement according to the invention including control circuits.
  • the embodiment shown of the known arrangement includes a self-commutating electric motor 1, for example, a motor provided with permanent-magnet energisation.
  • the motor 1 is connected in series with a heating element 2, which serves as a series resistor for the motor and the resistance of which is chosen so that the motor has a highly exaggerated series characteristic.
  • the motor is also connected in series with a controlled rectifier (thyristor) 3 the control electrode, or gate, of which is connected to a terminal 4.
  • a supply voltage V- is applied to this series combination of the heating element 2, the motor 1 and the thyristor 3 via terminals 6 and 6.
  • the speed of the motor is controlled by controlling the firing instant of the thyristor 3, i.e., by applying a trigger pulse to the terminal 41 at a desired instant.
  • This has the disadvantage that the likelihood of radiofrequency interference is great, for the thyristor current is switched on at an instant at which the voltage across this element has a positive value, which may give rise to considerable current variations.
  • the current through the heating element 2 is entirely determined by the motor current. Current is only supplied to the heating element during the part of the positive half-cycle of the supply voltage V- in which the thyristor is conductive, so that the generation of heat depends entirely on the motor conditions.
  • a switch 5 is provided which enables the heating element 2 to be directly connected to the supply voltage during the stationary periods of the motor. Heat dissipation naturally is entirely dependent on the duration of these stationary periods which may widely differ in the various washing programs.
  • FIG. 2 shows a first embodiment of the arrangement according to the invention.
  • the arrangement shown in FIG. 2 include the series combination of a heating element 2, a motor 1 and a controlled rectifier 3", the supply voltage V- being applied to this series combination via terminals 6 and 6.
  • the rectifier 3" used in this case is a controlled bidirectional rectifier (triac), however, it may alternatively be a thyristor.
  • the series combination of the motor 1 and the first rectifier 3 in this embodiment is shunted by a second bidirectional rectifier 7.
  • the triggering signals for both rectifiers are supplied by a control device 8.
  • the use of the second rectifier 7 provides a speed control for the motor I which is quite different from that used in the known arrangement, as will be explained with reference to the waveforms of the various currents shown in FIG. 4.
  • a control pulse is applied to the rectifier 3.
  • a motor current I will start flowing, and the current I flowing through the heating element is equal to the current I,.
  • the heating element 2 is directly connected to the supply voltage via the second rectifier 7, so that the current I flowing through this element will show an abrupt variation.
  • the current I, flowing through the second rectifier 7 is equal to the difference between the currents I and I,.
  • the second rectifier 7 may or may not be triggered again. If at this instant t, a new trigger pulse is supplied to the second rectifier, this rectifier will remain conducting and the sign of the current direction will be reversed.
  • a first advantage of the aforedescribed motor speed control permitted by the arrangement according to the invention is that the power supplied to the heating element 2 is substantially independent of this speed control.
  • FIG. 4 shows that the waveform of the current I flowing through the heating element is substantially sinusoidal. When the instant r, is varied, the sudden change of this waveform will follow this variation, the overall power supplied to the heating element will be substantially constant. Hence, substantially maximum power is supplied to the heating element irrespective of the motor conditions. If the second rectifier 7 is not retriggered at the instant t the power supplied to the heating element is halved. Thus, triggering of this second rectifier 7 not only provides a motor speed control but also enables the power supplied to the heating element to be controlled and to be substantially independent of the motor conditions. Triggering the second rectifier 7 alone at the passages through zero of the supply voltage V- provides maximum heating in the stationary condition of the motor.
  • the invention also enables the first rectifier to be triggered at the instant at which the voltage across it is zero, i.e., at the instant at which the supply voltage V- is equal to the back E.M.F. of the motor I. This method of triggering greatly reduces the risk of radio-frequency interference.
  • the variations of the line load will be small because when the heating element is switched to full power, current is supplied to it continuously and not, as in the known circuit arrangement, at intervals.
  • the fact that the first rectifier 3 is a bidirectional rectifier has the advantage of permitting the direction of rotation of the motor to be reversed by fully electronic means, for triggering this rectifier at the instant t instead of at the instant t, causes the direction of the current flowing through the motor to be reversed.
  • the speed control is effected by triggering the second rectifier 7 during the negative half-cycle of the supply voltage.
  • FIG. 3 shows a second simple embodiment of the arrangement according to the invention.
  • the first rectifier 3' connected in series with the motor is a diode.
  • the motor current is automatically switched on at the instant at which the voltage across this diode exceeds the threshold value thereof.
  • a second diode 3 having a pass direction opposite to that of the first diode and a switch 9 are provided.
  • the direction of current flow through the motor can be reversed by changing over the switch 9 by means of the control device 8.
  • Speed control and regulation of the power supplied to the heating element 2 are again effected by means of the second rectifier 7 which is triggered by the control device 8.
  • FIG. 5 shows, by way of example, an arrangement according to the invention which includes control circuits.
  • the motor circuit diagram is enclosed in a block M.
  • the trigger pulses for the gates of the rectifiers 3 and 7 are obtained by means of a trigger circuit TR and a control device D.
  • a square-wave voltage corresponding to a half-cycle of the supply voltage V- is derived from the supply voltage V- by means of the trigger circuit TR.
  • This square-wave voltage is applied to the control device D, in this case to the base of a transistor Tr
  • the collector of this transistor Tr is connected to the base of a transistor Tr
  • Two further transistors Tr and Tr are driven by means of these two transistors.
  • the collector voltages of the transistors 'Ir, and Tr determine the voltages at the gates of the rectifiers 3 and 7 and hence their conducting or non-conducting conditions.
  • the collector of the transistor Tr will assume a negative potential, permitting the rectifier 3 to become conducting, so that current is supplied to the motor, for example, during the positive half cycle of the supply voltage V-
  • the square-wave voltage collapses the collector voltage of the transistor Tr, becomes negative and the rectifier element 7 becomes conducting, so that current is supplied to the heating element 2 during the negative halfcycle of the supply voltage V-'also.
  • the speed control is effected by means of a tachogenerator device S.
  • the transistor Tr When the first rectifier is conducting, the transistor Tr: is non-conducting, so that its collector voltage is high. This collector voltage is applied to the emitter of the transistor Tr
  • the collector current of this transistor Tr is determined by the voltage applied to its base by the tachogenerator and is used to charge a capacitor C connected between the collector of the transistor Tr, and the base of the transistor Tr,.
  • the transistor Tr becomes conducting and the rectifier 7 is triggered. Consequently this triggering instant is determined by the voltage from the tachogenerator and hence by the motor speed.
  • the back E.M.F. of the motor may also be used as an indication of the speed.
  • a capacitor C is included in the connection between the collector of the transistor Tr and the base of the transistor Tr-,.
  • the capacitors C and C serve'to limit the durations of the trigger pulses. Should a trigger pulse be applied to the series rectifier 3 during an entire half-cycle of the supply voltage, the motor may be short-circuited, since at the instant at which the motor current becomes zero this trigger pulse would still be present and at the same time the second rectifier 7 would be conducting, so that the direction of the current flow through the motor may be reversed. This condition persists until the back E.M.F. is zero and hence the motor is stationary.
  • the capacitors C and C limit the durations of the trigger pulses, because they are charged via the resistors used. Further capacitors (C and C are provided to suppress the influence of interference signals.
  • control device D includes four transistors Tr Tr Tr and Tr
  • the collector emitter path of the transistor Tr shunts the base emitter path of the transistor Tr When a positive voltage is applied to the base of the transistor Tr, the base emitter path of the transistor Tr is substantially shortcircuited, so that the collector voltage of this transistor always is high and the first rectifier 3 is not triggered,
  • the transistor Tr is connected in series with a base resistor R u of the transistor Tr.,.
  • R u base resistor
  • the second rectifier 7 can be triggered.
  • the rectifier 7 cannot be triggered, so that power can only be supplied to the heating element via the motor current.
  • maximum power may be supplied to the heating element by means of transistors Tr and Tr If, during the washing program, the motor is in a stationary condition, a positive voltage is applied to the base of the transistor Tr If maximum heat dissipation is desired, a positive voltage is also applied to a terminal Q and hence to the base of the transistor Tr As a result, during the entire cycle of the supply voltage a trigger pulse is applied to the rectifier 7 and hence maximum power is supplied to the heating element.
  • the cycle of operation of the motor i.e., the periods during which the motor is required to run and to be stationary, and the reversal of its direction of rotation are effected by means of an astable multivibrator A and a bistable multivibrator B.
  • the cycle periods of the astable multivibrator A may be interchanged by an inverter comprising transistors Tr and Tr Depending upon the voltage at a terminal P (base of the transistor Tr either an end 10 or an end 11 of a resistor R is connected to the supply via a diode D or a diode D respectively.
  • a choice may be made between a quick operating rhythm of the motor (short stationary periods and long running period) and a slow operating rhythm (long stationary periods and short running periods).
  • the output voltage of this astable multivibrator A which voltage corresponds to the desired running period, is applied to the bistable multivibrator B. This ensures reversal of the direction of rotation of the motor.
  • the output voltages of this bistable multivibrator are applied via diodes D and D-, to the trigger circuit and determine during which half-cycle of the supply voltage V- this trigger circuit applies a square-wave voltage to the control device (base of the transistor Tr).
  • the input of the astable multivibrator A is also connected to the transistor Tr so that during the stationary period of the motor the series rectifier 3 is not triggered, and to the transistor Tr so that during this stationary period the application or non-application of a positive voltage to the terminal Q (base of the transistor Tr permits a choice to be made between maximum and minimum dissipation.
  • a control circuit for a self-commutating electric motor comprising, a pair of input terminals adapted for connection to a source of supply voltage, an electric heating element, a first rectifier, means connecting the heating element, the motor and the first rectifier in a series circuit across said input terminals, a bidirectional controlled rectifier connected across the series combination of the motor and the first rectifier and in series with the heating element across the input terminals,
  • first means for selectively applying a first control signal to the control electrode of said bidirectional rectifier to control the conduction period thereof in a manner to regulate the motor current and thereby control the motor speed.
  • a control circuit as claimed in claim 1 wherein the first rectifier comprises a bidirectional controlled rectifier having a control electrode connected to a control device for selectively supplying control signals to said control electrode to control the conduction of said first rectifier.
  • a control circuit as claimed in claim 3 further comprising, a second diode connected to the motor with opposite polarity to that of the first diode, and a switching element having first and second positions for selectively connecting said first and second diodes, respectively, in series with the motor and the heating element across said input terminals.
  • a control circuit as claimed in claim wherein said first control signal applying means includes means for selectively applying a third control signal to the control electrode of the bidirectional rectifier at the start of the next half cycle of the supply voltage.
  • said first control signal applying means includes means for selectively applying a third control signal to the control electrode of the first bidirectional rectifier during alternate half cycles of the AC supply voltage that follow the half cycles during which the first control signal is applied to the control electrode of the first bidirectional rectifier.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Ac Motors In General (AREA)
  • Rectifiers (AREA)
  • Control Of Multiple Motors (AREA)
US3764822D 1971-07-03 1972-06-29 Arrangement for driving the drum of a washing machine Expired - Lifetime US3764822A (en)

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NL7109226A NL7109226A (it) 1971-07-03 1971-07-03

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US (1) US3764822A (it)
CA (1) CA954615A (it)
DE (1) DE2232041A1 (it)
ES (1) ES404450A1 (it)
FR (1) FR2144747A1 (it)
GB (1) GB1358494A (it)
IT (1) IT958656B (it)
NL (1) NL7109226A (it)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4042865A (en) * 1973-03-08 1977-08-16 Sevcon Limited Separately excited D.C. motors
US4769582A (en) * 1979-11-12 1988-09-06 U.S. Philips Corporation Low vibration pulse drive device for an electric motor
WO1998019388A2 (en) * 1996-10-28 1998-05-07 Philips Electronics N.V. Speed control for the fan motor of a hot-air appliance
EP0921888A1 (en) * 1996-08-12 1999-06-16 Cooper Industries, Inc. Portable electric desoldering tool
US6337523B1 (en) 2000-02-10 2002-01-08 Troy Video Recording Services, Inc. Automated operation of silicon controlled rectifier switches using sensors such as Schmitt devices
US20050189929A1 (en) * 2002-08-14 2005-09-01 Detlef Schulz Apparatus for controlling the power of an AC voltage supplying an electrical consumer by phase control and method for reducing harmonics
US20060273751A1 (en) * 2005-06-06 2006-12-07 Lutron Electronics Co., Ltd. Method and apparatus for quiet variable motor speed control
US20070120521A1 (en) * 2003-12-11 2007-05-31 Gerhard Kurz Apparatus for power control by phase gating and a method for harmonic reduction
US7489094B2 (en) 2005-11-18 2009-02-10 Lutron Electronics Co., Inc. Method and apparatus for quiet fan speed control
US20090062083A1 (en) * 2007-08-31 2009-03-05 Matsushita Electric Works, Ltd. Rocking type exercising apparatus
WO2011076827A3 (de) * 2009-12-23 2012-08-16 Robert Bosch Gmbh Bremseinrichtung für einen universalmotor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3411045A1 (de) * 1984-03-26 1985-09-26 Conrad Engelke GmbH & Co KG, 3000 Hannover Antrieb einer wasch- und schleudermaschine fuer das waschen von bettfedern

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3638090A (en) * 1968-05-30 1972-01-25 Philips Corp Driving arrangement for the drum of a washing machine

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3638090A (en) * 1968-05-30 1972-01-25 Philips Corp Driving arrangement for the drum of a washing machine

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4042865A (en) * 1973-03-08 1977-08-16 Sevcon Limited Separately excited D.C. motors
US4769582A (en) * 1979-11-12 1988-09-06 U.S. Philips Corporation Low vibration pulse drive device for an electric motor
EP0921888A1 (en) * 1996-08-12 1999-06-16 Cooper Industries, Inc. Portable electric desoldering tool
EP0921888A4 (en) * 1996-08-12 1999-12-22 Cooper Ind Inc PORTABLE ELECTRICAL DESOLDERING TOOL
WO1998019388A2 (en) * 1996-10-28 1998-05-07 Philips Electronics N.V. Speed control for the fan motor of a hot-air appliance
WO1998019388A3 (en) * 1996-10-28 1998-06-25 Philips Electronics Nv Speed control for the fan motor of a hot-air appliance
US6337523B1 (en) 2000-02-10 2002-01-08 Troy Video Recording Services, Inc. Automated operation of silicon controlled rectifier switches using sensors such as Schmitt devices
US7397225B2 (en) * 2002-08-14 2008-07-08 Gerhard Kurz Apparatus for controlling the power of an AC voltage supplying an electrical consumer by phase control and method for reducing harmonics
US20050189929A1 (en) * 2002-08-14 2005-09-01 Detlef Schulz Apparatus for controlling the power of an AC voltage supplying an electrical consumer by phase control and method for reducing harmonics
US7408320B2 (en) * 2003-12-11 2008-08-05 Gerhard Kurz Apparatus for power control by phase gating and a method for harmonic reduction
US20070120521A1 (en) * 2003-12-11 2007-05-31 Gerhard Kurz Apparatus for power control by phase gating and a method for harmonic reduction
US7330004B2 (en) 2005-06-06 2008-02-12 Lutron Electronics Co., Inc. Method and apparatus for quiet variable motor speed control
US20060273751A1 (en) * 2005-06-06 2006-12-07 Lutron Electronics Co., Ltd. Method and apparatus for quiet variable motor speed control
US7489094B2 (en) 2005-11-18 2009-02-10 Lutron Electronics Co., Inc. Method and apparatus for quiet fan speed control
US20100109597A1 (en) * 2005-11-18 2010-05-06 Lutron Electronics Co., Inc. Method and apparatus for quiet fan speed control
US8193744B2 (en) 2005-11-18 2012-06-05 Lutron Electronics Co., Inc. Method and apparatus for quiet fan speed control
US20090062083A1 (en) * 2007-08-31 2009-03-05 Matsushita Electric Works, Ltd. Rocking type exercising apparatus
WO2011076827A3 (de) * 2009-12-23 2012-08-16 Robert Bosch Gmbh Bremseinrichtung für einen universalmotor
CN102742146A (zh) * 2009-12-23 2012-10-17 罗伯特·博世有限公司 用于通用马达的制动设备
US20120319627A1 (en) * 2009-12-23 2012-12-20 Robert Bosch Gmbh Braking Device for a Universal Motor
CN102742146B (zh) * 2009-12-23 2015-12-09 罗伯特·博世有限公司 用于通用马达的制动设备
US9590538B2 (en) * 2009-12-23 2017-03-07 Robert Bosch Gmbh Braking device for a universal motor

Also Published As

Publication number Publication date
CA954615A (en) 1974-09-10
GB1358494A (en) 1974-07-03
ES404450A1 (es) 1975-06-16
NL7109226A (it) 1973-01-05
FR2144747A1 (it) 1973-02-16
IT958656B (it) 1973-10-30
DE2232041A1 (de) 1973-01-18

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