US20110052420A1 - Liquid-conducting pump with dc motor and power supply with closed-loop control - Google Patents

Liquid-conducting pump with dc motor and power supply with closed-loop control Download PDF

Info

Publication number
US20110052420A1
US20110052420A1 US12/871,290 US87129010A US2011052420A1 US 20110052420 A1 US20110052420 A1 US 20110052420A1 US 87129010 A US87129010 A US 87129010A US 2011052420 A1 US2011052420 A1 US 2011052420A1
Authority
US
United States
Prior art keywords
pump
power supply
supply unit
pump according
motor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/871,290
Other languages
English (en)
Inventor
Hans-Georg Hagleitner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of US20110052420A1 publication Critical patent/US20110052420A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D15/00—Control, e.g. regulation, of pumps, pumping installations or systems
    • F04D15/0066—Control, e.g. regulation, of pumps, pumping installations or systems by changing the speed, e.g. of the driving engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
    • F04B17/03—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by electric motors

Definitions

  • the invention relates to a pump for conveying liquids, in particular water, having a direct-current motor and a power supply unit for rectifying and/or converting the AC voltage or DC voltage which is applied to the power supply unit.
  • direct-current motors are frequently used in particular for relatively small pumps which have to have only a low feed power.
  • the pumps which are used in the prior art with a direct-current motor have an external power supply unit, which rectifies the AC voltage applied to the power supply unit and, depending on the design of the power supply unit, transforms the voltage down, that is to say it steps it down.
  • the output voltage of the power supply unit is constant, and therefore it is not possible to react, or is possible to react only in a complicated and cumbersome manner, to any change in the rotation speed of the pump motor, for example caused by a change in the viscosity of the liquid to be pumped, by wear to the pump, or other load-dependent factors.
  • the invention is based on the object of specifying a pump having a direct-current motor, which avoids the above disadvantages and makes it possible in an easy way to keep the rotation speed of the pump motor and/or the pump feed power substantially constant in the event of any load changes, or to allow the feed power to follow a predetermined profile.
  • the power supply unit has a closed control loop for controlling a controlled variable of the pump.
  • This control system makes it possible to change the controlled variable to a value which is predetermined by a reference variable, wherein the reference variable is in this case given, for example, by the pump feed power, and to maintain the controlled variable at this value, even in the event of disturbance influences. It is likewise possible to design the control system such that the controlled variable follows a predetermined profile.
  • the closed control loop reacts to changes in the controlled variables, such as those caused by the so-called disturbance variables, by varying the manipulated variables, and in this case controls the controlled variable such that the corresponding desired profile of the controlled variable is achieved.
  • the reference variable can in this case itself be generated by an external appliance, or else can be set directly, for example at the pump.
  • Pumps such as these with a power supply unit and a closed control unit can be used particularly preferably in metering technology, wherein the closed control loop makes it possible to keep the controlled variable at a value which is predetermined by the reference variable, that is to say for example by the feed power.
  • Specific application options for pumps according to the invention in this case arise, for example, in the domestic field, where washing machines or kitchen appliances such as dishwashers, fan ovens or tape machines can be provided with pumps such as these. Pumps according to the invention can also usefully be used in health facilities such as swimming baths or saunas, as well as for water processing installations.
  • the electronic components for rectification and step-down conversion of the AC voltage which is applied to the power supply unit that is to say for transformation of the AC voltage applied to the power supply unit to a lower value are already known per se in the prior art, for example in the form of a switch-mode power supply, which is also referred to as a switching mode power supply (SMPS).
  • SMPS switching mode power supply
  • step-down conversion of the AC voltage which is applied to the power supply unit it is also possible in conjunction with high-voltage direct-current motors to provide the power supply unit with electronic components which carry out step-up conversion of the AC voltage which is applied to the power supply unit, that is to say transformation of the AC voltage applied to the power supply unit to a higher value.
  • a combination of step-down and step-up converters can also be used.
  • converters such as these are already known in the prior art, in the form of so-called Buch boost converters.
  • the power supply unit not to rectify AC voltage, but to carry out only the step-down and/or step-up conversion of the DC voltage applied to the power supply unit.
  • a reference variable produces a nominal value of a variable to be controlled, the so-called controlled variable.
  • the controlled variable should then follow the predetermined profile of the reference variable.
  • the reference variable is only a simple (constant) value at which the controlled variable should be kept, even under the influence of disturbance factors.
  • brushless-direct current motors In addition to direct-current motors with mechanical commutators, as has been known for a long time, and in which brushes composed of carbon or graphite can slide on the circumference of the commutator in order to supply the current, brushless-direct current motors (brushless DC motors) have also recently become known. These motors have been found to have the disadvantage that the commutation is carried out electronically, and that the rotation speed of a brushless motor such as this can thus be controlled in a similar manner to the rotation speed of an alternating-current motor via the frequency, where a frequency converter must be used for this purpose. However, such control is many times more complex than that for a direct-current motor with a mechanical commutator, where the rotation speed of the motor is directly proportional to the DC voltage applied to the armature of the motor.
  • a direct-current motor which has a mechanical commutator can be used in the pump. Since, in this case, the rotation speed of the motor is directly proportional to the DC voltage applied to the armature of the motor, the control system can be implemented particularly easily, in particular for characteristic variables which are dependent on the rotation speed, and there is no need for complicated electronic switching fittings, which are always also subject to defects.
  • the pump feed power in this case represents the controlled variable.
  • the aim of the closed control loop is then to keep the feed power substantially constant.
  • the pump feed power can be measured by a flow sensor.
  • the controlled variable is given by the rotation speed of the motor which, for example, can be measured directly on the motor shaft by means of a tachogenerator or an encoder.
  • Further possible controlled variables are the electromotive force induced in the motor, the back-emf (back-induction voltage) or else the current drawn by the motor, which can be measured by means of a so-called shunt resistor in the motor circuit.
  • a combination of a plurality of these measurement variables as controlled variable is also feasible.
  • the controlled variable itself is in this case preferably measured continuously and is compared with the reference variable in a regulator. Feeding back the actual value of the controlled variable induces negative feedback, which influences the behavior of the control loop.
  • an actuating element varies a manipulated variable in the control loop such that the controlled variable returns to the value of the reference variable.
  • This type of closed-loop control is achieved by negative feedback, thus stabilizing the control loop.
  • the analogue voltage on the output side of the power supply unit may be used as a manipulated variable, since the rotation speed of the direct-current motor with a mechanical commutator is directly proportioned to this voltage, if this is applied as the input voltage to the motor and is transmitted to the commutator by the brushes.
  • a DC voltage of 0 volts to 5 volts may correspond to a pump feed power of 0 liters per hour to 8 liters per hour.
  • the manipulated variable may be implemented by means of a pulse-width-modulated signal, a resistance value or a digital signal.
  • the pulse-width-modulated signal can change between a DC voltage of 0 volts and 5 volts and in the process may have a variable duty ratio of 0% to 100%, which itself may in turn correspond to a pump feed power of 0 liters per hour to 8 liters per hour.
  • a combination of a plurality of the abovementioned manipulated variables is also possible as the manipulated variable for the control loop according to the invention.
  • the essential feature is that a change in the manipulated variable results in a change in the controlled variable in the controlled system, that is to say for example the rotation speed of the motor or the pump feed power.
  • the relationship between the manipulated variable and the controlled variable which results from the design and configuration of the controlled system, that is to say of the corresponding components of the pump, in other words the influence of the manipulated variable on the controlled variable and/or the effect of the negative feedback may be known or can be modeled.
  • the system identification it is also possible for the system identification to be carried out partially or exclusively using measured values of the input and output behavior of the pump.
  • the disturbance variable of the closed control loop is given by a load-dependent rotation-speed change. Load-dependent rotation-speed changes such as these may have various causes which can result, for example, from the viscosity of the liquid to be pumped, the pump wear or further phenomena which influence the feed pressure.
  • Motors which use permanent magnets instead of electromagnets are in this case included in the motors with external excitation.
  • Special forms of direct-current motors with mechanical commutators, such as a disk-rotor motor, are likewise possible.
  • the power supply unit for the pump has the purpose on the one hand of rectifying the AC voltage supplied from the public mains system and on the other hand of transforming it to a lower or a higher value, that is to say to step it down or to step it up. During operation with direct current, there is no need for rectification.
  • this power supply unit comprises an inductor which is in the form of a transformer and is also referred to as a constant-current transformer (energy-storage inductor).
  • the inductor has a coil, which may be in the form of an air-cored coil or a coil with a ferrite or iron core.
  • the ratio of the input voltage and output voltage is governed primarily by the circuit and the drive (pulsing) of the inductor.
  • the power supply unit of the pump comprises an RF transformer, wherein this RF transformer has an induction coil with primary and secondary windings which are coupled via a ferrite core or an iron core, wherein the ferrite core or iron core can be completely closed or may have an air gap.
  • the ratio of the inductances, which are governed by the core material and the respective number of turns, is a major factor governing the ratio of the input voltage and output voltage of the transformer, and in addition the output voltage can also be adapted by pulsing of the primary coil.
  • Transformers such as these are known per se for operation of low-power electronic circuits, for example in the case of switch-mode power supplies (SMPS). In this case, it may be particularly advantageous to reduce the voltage by means of a so-called step-down converter (Buck converter). Electronic components such as these for power supply units and step-down converters without transformers are already known per se. Step-up converters can be used to increase the voltage, in which case it is possible to use converters which represent a combination of step-down and step-up converters, and which are known commercially via the expressions converter or, specifically Buck boost converter.
  • SMPS switch-mode power supplies
  • the power supply unit in one preferred embodiment of the invention includes the closed-loop control unit and, additionally or alternatively, the open-loop control unit which in the end controls the pump motor.
  • the closed-loop control unit comprises a regulator for comparing the reference variable and the controlled variable, as well as an actuating element for preferably automatically setting the manipulated variable.
  • the open-loop control unit prefferably arranged in the regulator or in the closed-loop control unit.
  • a power supply unit as mentioned above which comprises the closed-loop control unit and/or the open-loop control unit, has been found to be particularly advantageous for a pump according to the invention, because the power supply unit, and therefore also the pump, can be designed in a space-saving manner. It is particularly preferable for a power supply unit such as this to be accommodated in the pump housing, which means that there is no longer any need for external appliances, except for the electrical power supply. In this case, it is possible for this power supply unit to be integrated directly in the pump head.
  • the type of pump is itself irrelevant in this case.
  • the invention relates to all types of pumps, for example peristalstic pumps, membrane pumps, eccentric pumps, etc.
  • the pump feed power is predetermined as an internal or external signal as a reference variable, which is intended to be kept at a constant value.
  • the closed control loop according to the invention allows this maintenance of the feed power since the closed-loop control makes it possible to compensate for any change in the feed pressure and the viscosity.
  • the pump has an apparatus for setting a desired feed power.
  • the pump it is also possible for the pump to have an interface by means of which a desired feed power can be transmitted from a separate apparatus. For example, it is possible to connect a computer or a processor unit to this interface, in which case this computer or this processor unit transmits data via the interface to the open-loop or closed-loop control unit.
  • the invention furthermore relates to a pump installation which has a plurality of pumps, wherein, as stated above, these pumps have a direct-current motor with mechanical commutators, as well as a power supply unit for rectification and/or transformation of the AC voltage or DC voltage applied to the power supply unit, and have a closed control loop for controlling a controlled variable of the pump.
  • a pump installation such as this which, for example, can be used as a metering installation in metering technology, has the advantage that each pump has its own power supply unit, as a result of which the pumps cannot influence one another.
  • the invention furthermore relates to a method for operating a pump, as described above, wherein a desired pump feed power is selected and the pump is controlled such that the desired feed power is substantially maintained by variation of the manipulated variable for the control loop of the pump.
  • FIG. 1 shows an exploded illustration of a pump with a power supply unit, which comprises a closed-loop control unit, integrated in the pump head,
  • FIG. 2 shows a schematic layout of a power supply unit according to the invention with a closed-loop control unit and open-loop control unit, as well as a connected pump motor and measurement apparatuses, and
  • FIG. 3 shows a diagram of the closed control loop according to the invention.
  • FIG. 1 shows an exploded illustration of the major components of a pump 1 according to the invention.
  • the pump motor 6 is arranged in the pump head 14 .
  • a board 16 is likewise integrated in the pump head 14 , on which board 16 the major electronic components are arranged, that is to say the power supply unit 2 with the closed-loop control unit 4 and the open-loop control unit 5 .
  • the pump is closed by the pump housing 15 .
  • further components and details of the pump 1 which are less relevant for the invention, are not shown here.
  • FIG. 2 shows a schematic illustration of the power supply unit 2 , which has a power area 3 in which the AC voltage VAC provided by the public mains system or a DC voltage provided by an external voltage source is applied to the input side of the power supply unit 2 , and is possibly rectified and stepped down, that is to say converted downward.
  • an electronic component without a transformer which is known per se, is used with a step-down converter 3 .
  • a closed-loop control unit 4 which has a regulator 12 and an actuating element.
  • the closed-loop control unit 4 determines a manipulated variable u which in this case is given by the output voltage of the power supply unit 2 , and is emitted via an open-loop control unit 5 to the motor 6 of the pump 1 . It is also possible for the open-loop control unit 5 to be part of the closed-loop control unit 4 .
  • the output voltage produced by the closed-loop control unit 4 is produced between the supply lines 10 and 10 ′ on the output side of the power supply unit 2 and may, for example, be between 0 V and 24 V (DC voltage).
  • the pump 1 itself can be disturbed by widely differing factors, such as a load-dependent rotation-speed change, wherein these variables are included as disturbance variables d in the control loop 11 .
  • the rotation speed of the motor 6 is used as the controlled variable y, and is monitored continuously by a tachogenerator 7 or an encoder, with the values of the rotation speed being transmitted by the supply line 8 to the closed-loop control unit 4 .
  • a further possible controlled variable y would be the current drawn by the motor 6 , which is measured via a shunt resistor 9 in the circuit of the motor 6 and is likewise transmitted via the supply lines 8 ′ and 8 to the closed-loop control unit 4 .
  • the controlled variable y that is to say by way of example the rotation speed of or the current drawn by the motor 6
  • the controlled system 13 which includes an actuating element, by varying the manipulated variable u, that is to say in this case by regulating the output voltage of the power supply unit 2 .
  • Such closed-loop control allows the rotation speed of the motor 6 to be kept at a constant value, as a result of which the feed power of the pump 1 is likewise essentially constant and independent of external influences, because changes, for example in the feed pressure and the viscosity for the liquid or liquids to be pumped, can be compensated for.
  • FIG. 3 shows a diagram of the closed control loop 11 of the pump 1 according to the invention.
  • the reference variable w is supplied to the open-loop control unit 5 , for example by generating it by means of an external appliance such as a metering appliance. A manual input is also feasible, and is then transmitted to the open-loop control unit 5 .
  • the reference variable w may be the analogue voltage value of the output voltage of the power supply unit 2 or of an external appliance, which corresponds to a certain rotation speed of the motor 6 of the pump 1 , and therefore to a certain feed power.
  • the reference variable w itself to be a predetermined feed power, and for the reference variable w or the controlled variable y to be converted in the regulator 12 , thus allowing these variables to be compared.
  • a pulse-width-modulated value or a digital signal can also be used as the reference variable.
  • the open-loop control system which in this exemplary embodiment is arranged in the regulator 12 , calculates a control difference (control error, control discrepancy) e by comparison of the reference variable w with the manipulated variable y.
  • the negative feedback z is also included in this, that is to say the actual value of the controlled variable y, which is transmitted via a return line in the closed control loop 11 to the closed-loop control unit 4 .
  • the regulator 12 processes the control difference e and passes a manipulated variable u which has been modified on the basis of this result on via the controlled system 13 , in which the controlled variable y is regulated.
  • the disturbance variables d are also included in the closed control loop 11 .

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Positive-Displacement Pumps (AREA)
  • Control Of Non-Positive-Displacement Pumps (AREA)
  • Control Of Direct Current Motors (AREA)
US12/871,290 2009-09-01 2010-08-30 Liquid-conducting pump with dc motor and power supply with closed-loop control Abandoned US20110052420A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ATA1368/2009 2009-09-01
AT0136809A AT509300A1 (de) 2009-09-01 2009-09-01 Pumpe mit netzgeräteregler

Publications (1)

Publication Number Publication Date
US20110052420A1 true US20110052420A1 (en) 2011-03-03

Family

ID=43216150

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/871,290 Abandoned US20110052420A1 (en) 2009-09-01 2010-08-30 Liquid-conducting pump with dc motor and power supply with closed-loop control

Country Status (3)

Country Link
US (1) US20110052420A1 (de)
EP (1) EP2290240A3 (de)
AT (1) AT509300A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160040686A1 (en) * 2014-08-07 2016-02-11 Johnson Electric S.A. Heating Pump
CN107548436A (zh) * 2015-05-11 2018-01-05 大陆汽车有限责任公司 用于运行流体输送系统的方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE202013011190U1 (de) * 2013-12-17 2014-03-19 Wisy Ag Haustechniksysteme, Filtertechnik Schaltautomat für eine Pumpensteuerung

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4299541A (en) * 1977-11-29 1981-11-10 Nikkiso Co., Ltd. Infusion solution injecting pump
US5548854A (en) * 1993-08-16 1996-08-27 Kohler Co. Hydro-massage tub control system
US6174136B1 (en) * 1998-10-13 2001-01-16 Liquid Metronics Incorporated Pump control and method of operating same
US6264431B1 (en) * 1999-05-17 2001-07-24 Franklin Electric Co., Inc. Variable-speed motor drive controller for a pump-motor assembly
US6414455B1 (en) * 2000-04-03 2002-07-02 Alvin J. Watson System and method for variable drive pump control
US6534940B2 (en) * 2001-06-18 2003-03-18 Smart Marine Systems, Llc Marine macerator pump control module
US6541947B1 (en) * 1998-09-10 2003-04-01 Robert Bosch Gmbh Step-down constant-current transformer
US6604909B2 (en) * 2001-03-27 2003-08-12 Aquatec Water Systems, Inc. Diaphragm pump motor driven by a pulse width modulator circuit and activated by a pressure switch
US6623245B2 (en) * 2001-11-26 2003-09-23 Shurflo Pump Manufacturing Company, Inc. Pump and pump control circuit apparatus and method
US20060073036A1 (en) * 2004-09-29 2006-04-06 Pascual Joseph A Pump assembly and fluid metering unit
US20070077153A1 (en) * 2005-09-30 2007-04-05 Austen Timothy F Rechargeable AC/DC pump
US20070154319A1 (en) * 2004-08-26 2007-07-05 Stiles Robert W Jr Pumping system with power optimization
US7290993B2 (en) * 2004-04-02 2007-11-06 Adaptivenergy Llc Piezoelectric devices and methods and circuits for driving same

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0619432B1 (de) * 1993-04-08 1996-10-09 Pumpenfabrik Ernst Vogel Gesellschaft m.b.H. Anlage mit mindestens einer Flüssigkeitspumpe

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4299541A (en) * 1977-11-29 1981-11-10 Nikkiso Co., Ltd. Infusion solution injecting pump
US5548854A (en) * 1993-08-16 1996-08-27 Kohler Co. Hydro-massage tub control system
US6541947B1 (en) * 1998-09-10 2003-04-01 Robert Bosch Gmbh Step-down constant-current transformer
US6174136B1 (en) * 1998-10-13 2001-01-16 Liquid Metronics Incorporated Pump control and method of operating same
US6264431B1 (en) * 1999-05-17 2001-07-24 Franklin Electric Co., Inc. Variable-speed motor drive controller for a pump-motor assembly
US6414455B1 (en) * 2000-04-03 2002-07-02 Alvin J. Watson System and method for variable drive pump control
US6604909B2 (en) * 2001-03-27 2003-08-12 Aquatec Water Systems, Inc. Diaphragm pump motor driven by a pulse width modulator circuit and activated by a pressure switch
US6534940B2 (en) * 2001-06-18 2003-03-18 Smart Marine Systems, Llc Marine macerator pump control module
US6623245B2 (en) * 2001-11-26 2003-09-23 Shurflo Pump Manufacturing Company, Inc. Pump and pump control circuit apparatus and method
US7290993B2 (en) * 2004-04-02 2007-11-06 Adaptivenergy Llc Piezoelectric devices and methods and circuits for driving same
US20070154319A1 (en) * 2004-08-26 2007-07-05 Stiles Robert W Jr Pumping system with power optimization
US20060073036A1 (en) * 2004-09-29 2006-04-06 Pascual Joseph A Pump assembly and fluid metering unit
US20070077153A1 (en) * 2005-09-30 2007-04-05 Austen Timothy F Rechargeable AC/DC pump

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160040686A1 (en) * 2014-08-07 2016-02-11 Johnson Electric S.A. Heating Pump
CN105465050A (zh) * 2014-08-07 2016-04-06 德昌电机(深圳)有限公司 加热泵
US10302098B2 (en) * 2014-08-07 2019-05-28 Johnson Electric International AG Heating pump
CN107548436A (zh) * 2015-05-11 2018-01-05 大陆汽车有限责任公司 用于运行流体输送系统的方法

Also Published As

Publication number Publication date
AT509300A1 (de) 2011-07-15
EP2290240A2 (de) 2011-03-02
EP2290240A3 (de) 2014-08-13

Similar Documents

Publication Publication Date Title
US10563332B2 (en) Closed-loop control device of a mechanical sewing machine and method for controlling the same
KR100692567B1 (ko) 스위칭모드 전원공급장치 및 절전모드 구현방법
JP5154588B2 (ja) スイッチング電源装置
US20040141339A1 (en) Switching power supply device
US20110052420A1 (en) Liquid-conducting pump with dc motor and power supply with closed-loop control
US9537350B2 (en) Switch-mode power supply with a dual primary transformer
US10199865B2 (en) High efficiency wireless power system
CN211142543U (zh) 一种洗衣机电路及洗衣机
CN102460953B (zh) 住宅自动化执行机构及对这种机构进行供电和控制的方法
EP3879694A1 (de) Steuergerät für einen generator
CN110401347B (zh) 直流电源装置
CN102761259B (zh) 定频式导通时间控制系统、方法以及电压调节器
US7091632B2 (en) Stabilization circuit for compensating fluctuations in a voltage at a user
US20220376614A1 (en) Power supply circuit and power supply device
JP2010200437A (ja) 電源装置
US20020080628A1 (en) Method and apparatus for reducing audible noise in a power supply transformer
AU2013204735B2 (en) Methods and systems for programming an electric motor
KR101341086B1 (ko) 출력전압 조절이 가능한 전압 자동 조정기
JP6287937B2 (ja) 電源システム
WO2024056703A1 (en) Led driver for controlling a led fixture and a method of controlling a led fixture
RU2487459C1 (ru) Устройство для стабилизации частоты вращения однофазного коллекторного электродвигателя
AU2015201770B2 (en) Self exciting alternator circuit
KR100629518B1 (ko) 다출력 스위칭 전원장치
KR910007201B1 (ko) 스위칭 모드 전원회로의 병렬접속방식
RU2491706C1 (ru) Устройство для стабилизации частоты вращения однофазного коллекторного электродвигателя

Legal Events

Date Code Title Description
STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION