WO1998019388A2 - Speed control for the fan motor of a hot-air appliance - Google Patents

Speed control for the fan motor of a hot-air appliance Download PDF

Info

Publication number
WO1998019388A2
WO1998019388A2 PCT/IB1997/001172 IB9701172W WO9819388A2 WO 1998019388 A2 WO1998019388 A2 WO 1998019388A2 IB 9701172 W IB9701172 W IB 9701172W WO 9819388 A2 WO9819388 A2 WO 9819388A2
Authority
WO
WIPO (PCT)
Prior art keywords
motor
hot
heating element
air appliance
mains voltage
Prior art date
Application number
PCT/IB1997/001172
Other languages
French (fr)
Other versions
WO1998019388A3 (en
Inventor
Wilhelmus Gerardus Maria Ettes
Original Assignee
Philips Electronics N.V.
Philips Norden Ab
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 Philips Electronics N.V., Philips Norden Ab filed Critical Philips Electronics N.V.
Publication of WO1998019388A2 publication Critical patent/WO1998019388A2/en
Publication of WO1998019388A3 publication Critical patent/WO1998019388A3/en

Links

Classifications

    • 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
    • A—HUMAN NECESSITIES
    • A45—HAND OR TRAVELLING ARTICLES
    • A45D—HAIRDRESSING OR SHAVING EQUIPMENT; EQUIPMENT FOR COSMETICS OR COSMETIC TREATMENTS, e.g. FOR MANICURING OR PEDICURING
    • A45D20/00—Hair drying devices; Accessories therefor
    • A45D20/22—Helmets with hot air supply or ventilating means, e.g. electrically heated air current
    • A45D20/30—Electric circuitry specially adapted for hair drying devices
    • 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
    • H02P25/14—Universal motors

Definitions

  • the invention relates to a hot-air appliance comprising: a heating element and a motor connected in series to receive a.c. mains voltage.
  • Such a hot-air appliance is known, inter alia from United States Patent US 4,323,761.
  • Such hot-air appliances are used as hair dryers, hot-air brushes or combs, and hair-drying hoods for personal care and in fan heaters for space heating.
  • the motor of the fan producing the stream of hot air is arranged in series with one of the heating elements.
  • the motor can be connected to a tapping of the heating element, as in the case of said United States Patent.
  • the motor can be an a.c. motor but frequently a d.c. motor is used. In the last-mentioned case the motor is connected to the heating element via a diode or a rectifier bridge.
  • the hot-air appliance of the type defined in the opening paragraph is characterized in that the hot-air appliance further comprises means for periodically short-circuiting the motor.
  • the motor is short-circuited in accordance with a given pattern in order to control the speed, instead of the entire series arrangement of the motor and heating element being turned on and turned off in order to control the speed.
  • the variation of the current through the series arrangement of the heating element and the motor is much smaller. This is because there is always a current through the heating element.
  • speed control is achieved with a comparatively low level of interference on the a.c. mains voltage.
  • Periodically short-circuiting the motor can be effected by means of an electronic switch, for example a triac.
  • the interference level can be reduced even further by means of a resistor in series with the electronic switch. This is because the current variation during short-circuiting of the motor is then even smaller.
  • Said resistor can take the form of a heating element, as a result of which the heat generated in this resistor assists in heating the air stream.
  • Figure 1 shows a circuit diagram of an embodiment of a hot-air appliance in accordance with the invention.
  • Figure 2 is an elevation showing a hair dryer in accordance with the invention.
  • FIG. 1 shows a circuit diagram of an embodiment of a hot-air appliance in accordance with the invention.
  • the appliance receives an a.c. mains voltage of 230 V on the mains voltage terminals L and N and is switched on by means of a power switch S in series with the mains voltage terminal L.
  • the mains voltage terminal N is the ground terminal.
  • the hot air is produced by a first heating element HI having a power of, for example, 440 W and connected in series with a fan motor M to the mains voltage terminals L and N.
  • the motor M is, by way of example, a 30 V d.c. motor connected via a rectifier bridge.
  • a d.c. motor with a rectifier bridge it is also possible to use an a.c.
  • the hot-air appliance further comprises a second heating element H2 having a power of, for example, 1200 W and connected in series with a triac T2 across the mains voltage terminals L and N.
  • the first heating element HI produces the primary heat and the second heating element H2 produces additional heat controllable by means of the triac T2.
  • An electronic switch in the present example a triac TI, is arranged in parallel with the combination of the rectifier bridge B and the d.c. motor M.
  • a control unit CU supplies trigger pulses to the gate of the triac TI and the gate of the triac T2. By periodically short-circuiting the motor M by means of the triac TI a speed control for the motor M is obtained.
  • Short-circuiting the motor M produces a comparatively small variation of the current through the first heating element HI, because the motor voltage is low with respect to the a.c. mains voltage. As a result of this, the interference on the a.c. mains voltage is small.
  • a series resistor Rl can be included in series with the triac TI in order to achieve a further reduction of the interference on the a.c. mains voltage. If desired, this series resistor can be a heating element, as a result of which the heat generated in this series resistor assists in heating the air.
  • the control unit CU is powered by a series arrangement of a capacitor Cl, a rectifier diode D and a smoothing capacitor C2 between the mains voltage terminals L and N, and a zener diode Z connected between the mains voltage terminal N and the node between the capacitor Cl and the rectifier diode D.
  • the control unit CU comprises a zero crossing detector ZC connected to the mains voltage terminal L by a resistor R2.
  • the output signal of the zero crossing detector ZC is applied to a temperature control unit Ul which drives the triac T2 on the basis of, for example, period control or multi-cycle control.
  • the temperature is controlled by means of a control signal on an input TC, which control signal is generated by a temperature controller RT.
  • the output signal of the zero crossing detector ZC is further applied to a speed control unit U2, which controls the triac TI for example through phase-angle control.
  • the speed of the motor M is controlled by a control signal SC, which control signal is generated by a speed controller RS.
  • the control unit can be implemented by means of a microcontroller or by means of commercially available integrated circuits such as the TDA 1023 (period control) and the TDA 1024 (phase-angle control). Zero crossing detectors are also available as integrated circuits.
  • the temperature can also be controlled by other means, for example by means of a heating element H2 which has been divided into sections which are supplied with mains voltage by means of mechanical switches or by means of relays.
  • FIG. 2 diagrammatically shows a hair dryer including the heating elements HI and H2, a fan F, a power switch S, the controls RS and RS arranged on the handle, and the control unit CU accommodated in the handle.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Cleaning And Drying Hair (AREA)
  • Direct Air Heating By Heater Or Combustion Gas (AREA)

Abstract

A hot-air appliance comprises a fan motor (M) connected in series with a heating element (H1) to receive a.c. mains voltage (L, N). The speed of the motor (M) is controlled by periodically short-circuiting the motor (M) by means of an electronic switch (T1).

Description

Speed control for the fan motor of a hot-air appliance
The invention relates to a hot-air appliance comprising: a heating element and a motor connected in series to receive a.c. mains voltage.
Such a hot-air appliance is known, inter alia from United States Patent US 4,323,761. Such hot-air appliances are used as hair dryers, hot-air brushes or combs, and hair-drying hoods for personal care and in fan heaters for space heating. The motor of the fan producing the stream of hot air is arranged in series with one of the heating elements. Alternatively, the motor can be connected to a tapping of the heating element, as in the case of said United States Patent. The motor can be an a.c. motor but frequently a d.c. motor is used. In the last-mentioned case the motor is connected to the heating element via a diode or a rectifier bridge.
In hair dryers, fan heaters etc. it is desirable to control the speed of the fan motor in order to enable the stream of heated air to be varied. For this purpose several techniques are available, such as multi-cycle control, pulse-width modulation and phase-angle control, the effective voltage across the motor being influenced by means of an electronic switch arranged in series with the heating element and the motor. A drawback of said techniques is that, depending on the type of control, they lead to a speed control which proceeds too abruptly, undesired motor vibrations, or too much interference on the applied a.c. mains voltage.
It is an object of the invention to provide a speed control for a hot-air appliance in which the fan motor is arranged in series with a heating element, which does not have said drawbacks or which mitigates said drawbacks. To this end the hot-air appliance of the type defined in the opening paragraph is characterized in that the hot-air appliance further comprises means for periodically short-circuiting the motor.
According to the invention only the motor is short-circuited in accordance with a given pattern in order to control the speed, instead of the entire series arrangement of the motor and heating element being turned on and turned off in order to control the speed. In this way, the variation of the current through the series arrangement of the heating element and the motor is much smaller. This is because there is always a current through the heating element. Thus, speed control is achieved with a comparatively low level of interference on the a.c. mains voltage.
Periodically short-circuiting the motor can be effected by means of an electronic switch, for example a triac. The interference level can be reduced even further by means of a resistor in series with the electronic switch. This is because the current variation during short-circuiting of the motor is then even smaller. Said resistor can take the form of a heating element, as a result of which the heat generated in this resistor assists in heating the air stream.
These and other aspects of the invention will be described and elucidated with reference to the accompanying drawings, in which:
Figure 1 shows a circuit diagram of an embodiment of a hot-air appliance in accordance with the invention; and
Figure 2 is an elevation showing a hair dryer in accordance with the invention.
In these Figures parts having like functions or purposes bear the same reference symbols.
Figure 1 shows a circuit diagram of an embodiment of a hot-air appliance in accordance with the invention. The appliance receives an a.c. mains voltage of 230 V on the mains voltage terminals L and N and is switched on by means of a power switch S in series with the mains voltage terminal L. The mains voltage terminal N is the ground terminal. The hot air is produced by a first heating element HI having a power of, for example, 440 W and connected in series with a fan motor M to the mains voltage terminals L and N. In the present case the motor M is, by way of example, a 30 V d.c. motor connected via a rectifier bridge. However, instead of a d.c. motor with a rectifier bridge it is also possible to use an a.c. motor. The hot-air appliance further comprises a second heating element H2 having a power of, for example, 1200 W and connected in series with a triac T2 across the mains voltage terminals L and N. The first heating element HI produces the primary heat and the second heating element H2 produces additional heat controllable by means of the triac T2. An electronic switch, in the present example a triac TI, is arranged in parallel with the combination of the rectifier bridge B and the d.c. motor M. A control unit CU supplies trigger pulses to the gate of the triac TI and the gate of the triac T2. By periodically short-circuiting the motor M by means of the triac TI a speed control for the motor M is obtained. Short-circuiting the motor M produces a comparatively small variation of the current through the first heating element HI, because the motor voltage is low with respect to the a.c. mains voltage. As a result of this, the interference on the a.c. mains voltage is small. At option, a series resistor Rl can be included in series with the triac TI in order to achieve a further reduction of the interference on the a.c. mains voltage. If desired, this series resistor can be a heating element, as a result of which the heat generated in this series resistor assists in heating the air.
The control unit CU is powered by a series arrangement of a capacitor Cl, a rectifier diode D and a smoothing capacitor C2 between the mains voltage terminals L and N, and a zener diode Z connected between the mains voltage terminal N and the node between the capacitor Cl and the rectifier diode D. The control unit CU comprises a zero crossing detector ZC connected to the mains voltage terminal L by a resistor R2. The output signal of the zero crossing detector ZC is applied to a temperature control unit Ul which drives the triac T2 on the basis of, for example, period control or multi-cycle control. The temperature is controlled by means of a control signal on an input TC, which control signal is generated by a temperature controller RT. The output signal of the zero crossing detector ZC is further applied to a speed control unit U2, which controls the triac TI for example through phase-angle control. The speed of the motor M is controlled by a control signal SC, which control signal is generated by a speed controller RS.
The control unit can be implemented by means of a microcontroller or by means of commercially available integrated circuits such as the TDA 1023 (period control) and the TDA 1024 (phase-angle control). Zero crossing detectors are also available as integrated circuits. The temperature can also be controlled by other means, for example by means of a heating element H2 which has been divided into sections which are supplied with mains voltage by means of mechanical switches or by means of relays.
Figure 2 diagrammatically shows a hair dryer including the heating elements HI and H2, a fan F, a power switch S, the controls RS and RS arranged on the handle, and the control unit CU accommodated in the handle.

Claims

CLAIMS:
1. A hot-air appliance comprising: a heating element (HI) and a motor (M) connected in series to receive a.c. mains voltage (L, N), characterized in that the hot-air appliance further comprises means (TI, CU) for periodically short-circuiting the motor (M).
2. A hot-air appliance as claimed in Claim 1, characterized in that the means comprise: an electronic switch (TI) arranged in parallel with the motor (M) and a circuit
(CU) for supplying a control signal to the electronic switch (TI) to turn on and turn off the electronic switch (TI).
3. A hot-air appliance as claimed in Claim 2, characterized in that a resistor (Rl) has been arranged in series with the electronic switch (TI).
4. A hot-air appliance as claimed in Claim 3, characterized in that the resistor (Rl) is a heating element.
5. A hot-air appliance as claimed in Claim 3, characterized in that the hot-air appliance further comprises: a further heating element (H2) connected in series with a further electronic switch (T2) to receive the a.c. mains voltage, said heating element (HI) and the further heating element (H2) being connected to a first mains voltage terminal (L), and the motor (M), the first-mentioned electronic switch (TI), the further electronic switch (T2) and the circuit (CU) for supplying the control signal being connected to a second mains voltage terminal (N).
6. A hot-air appliance as claimed in Claim 1, 2, 3, 4 or 5, characterized in that the motor (M) is a d.c. motor connected via a rectifier bridge (B).
PCT/IB1997/001172 1996-10-28 1997-09-26 Speed control for the fan motor of a hot-air appliance WO1998019388A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP96202994.8 1996-10-28
EP96202994 1996-10-28

Publications (2)

Publication Number Publication Date
WO1998019388A2 true WO1998019388A2 (en) 1998-05-07
WO1998019388A3 WO1998019388A3 (en) 1998-06-25

Family

ID=8224525

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB1997/001172 WO1998019388A2 (en) 1996-10-28 1997-09-26 Speed control for the fan motor of a hot-air appliance

Country Status (1)

Country Link
WO (1) WO1998019388A2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006107503A1 (en) * 2005-03-31 2006-10-12 Wayne-Dalton Corp. Electric motor control circuit having reduced electromagnetic interference emissions
CN109617470A (en) * 2018-11-07 2019-04-12 舒可士（深圳）科技有限公司 The control system of hair dryer

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3764822A (en) * 1971-07-03 1973-10-09 Philips Corp Arrangement for driving the drum of a washing machine
EP0028386A2 (en) * 1979-11-02 1981-05-13 Robert Bosch Gmbh Control arrangement for a wiper system of motor vehicle wind-shields
US4327278A (en) * 1979-09-10 1982-04-27 Conair Corporation Simplified multiple speed hair dryer
DE3139199A1 (en) * 1981-10-02 1983-04-21 Braun Ag, 6000 Frankfurt Method and arrangement for controlling and regulating the heating power of an electrical heating and/or drying apparatus
US4719395A (en) * 1986-12-22 1988-01-12 Omron Tateisi Electronics Co. Variable speed control switch for an electric tool including a DC motor
US5571062A (en) * 1995-11-02 1996-11-05 Kb Electronics, Inc. Treadmill safety module

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3764822A (en) * 1971-07-03 1973-10-09 Philips Corp Arrangement for driving the drum of a washing machine
US4327278A (en) * 1979-09-10 1982-04-27 Conair Corporation Simplified multiple speed hair dryer
EP0028386A2 (en) * 1979-11-02 1981-05-13 Robert Bosch Gmbh Control arrangement for a wiper system of motor vehicle wind-shields
DE3139199A1 (en) * 1981-10-02 1983-04-21 Braun Ag, 6000 Frankfurt Method and arrangement for controlling and regulating the heating power of an electrical heating and/or drying apparatus
US4719395A (en) * 1986-12-22 1988-01-12 Omron Tateisi Electronics Co. Variable speed control switch for an electric tool including a DC motor
US5571062A (en) * 1995-11-02 1996-11-05 Kb Electronics, Inc. Treadmill safety module

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006107503A1 (en) * 2005-03-31 2006-10-12 Wayne-Dalton Corp. Electric motor control circuit having reduced electromagnetic interference emissions
CN109617470A (en) * 2018-11-07 2019-04-12 舒可士（深圳）科技有限公司 The control system of hair dryer

Also Published As

Publication number Publication date
WO1998019388A3 (en) 1998-06-25

Similar Documents

Publication Publication Date Title
KR100548730B1 (en) Appliance power supply
US5662025A (en) Control circuit for an electric cooker
WO1998019388A2 (en) Speed control for the fan motor of a hot-air appliance
IE47893B1 (en) Electric hairdrier
US5943470A (en) Low-voltage generation in mains-powered hot-air appliances having a fan motor
KR0164516B1 (en) Heater control circuit
TWI609569B (en) Hairdryers and fan rotation speed control modules thereof
JPH0418483Y2 (en)
WO2004019726A1 (en) Hair dryer with improved heating power control and circuits therefor
JP2640060B2 (en) Hair dryer
JP3151560B2 (en) Dryer
EP1700373B1 (en) Rotation speed control circuit
JPS60148505A (en) Hair dryer
KR970000991Y1 (en) Hair dryer
KR100210075B1 (en) Heater control apparatus for microwave oven
KR100337914B1 (en) Driving control circuit of a hood DC motor for a microwave oven over range
KR940003317Y1 (en) Air blowers
JP2732834B2 (en) Automatic voltage switching circuit
DE59102722D1 (en) Mains powered hot air device.
KR200343817Y1 (en) Thermostste-stable control circuit
KR19980077628A (en) Power control device of automatic hot water cleaning toilet
KR910000411Y1 (en) A controlling circuit of drying in dishes cleaner
KR0164751B1 (en) Circuit for stabilizing effective voltage in electric apparatus
JPH0313600Y2 (en)
JPS63270004A (en) Hair dryer

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): CN JP

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE

AK Designated states

Kind code of ref document: A3

Designated state(s): CN JP

AL Designated countries for regional patents

Kind code of ref document: A3

Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase in:

Ref country code: JP

Ref document number: 1998520224

Format of ref document f/p: F

122 Ep: pct application non-entry in european phase