EP1899525B1

EP1899525B1 - A washer/dryer and a control method

Info

Publication number: EP1899525B1
Application number: EP06780021.9A
Authority: EP
Inventors: Hakan Ozkahraman
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2005-07-05
Filing date: 2006-07-05
Publication date: 2015-03-04
Anticipated expiration: 2026-07-05
Also published as: WO2007004198A1; EP1899525A1; WO2007004198A8

Description

The present invention relates to a washer/dryer wherein possible failures due to reasons such as voltage drops or overloading are prevented and a control method thereof.
In washer/dryers, the laundry to be dried is placed inside a drum actuated by an electric motor and the air heated by a heater is blown over for drying. When the drum is loaded with more laundry than is allowed, the electric motor rotating the drum tries to overcome this extra torque and starts heating. The motor temperature is detected by a thermal unit (thermal protector) situated on the windings and when a certain temperature value is exceeded, the thermal element cuts off the current to the motor, stopping the motor. In washer/dryers, the electric motor activating the drum generally also activates the fan that provides blowing hot air over the laundry. The temperature of the heater is controlled by continuously blowing air over it during the drying process. When the electric motor activating the drum stops due to overheating, the fan blowing air over the heater also stops and since the current continues to flow to the heater, it continues to be heated. When the temperature of the heater exceeds a certain value, the thermostats controlling the temperature of heater are energized and cut off the current delivered to the heater for providing safety. In state-of-the-art, various safety systems are utilized that are energized in case the motor and the heater are overheated. When the electric motor is overheated, the thermal unit cuts off the current, stopping the electric motor, however even if the electric motor is safeguarded by the thermal unit against overheating, it nevertheless operates in overload conditions for a long time and the motor windings are impaired. When this condition is repeated frequently, it reduces the life of the electric motor. Sometimes the washer/dryers have to operate with low voltage. In order to operate the electric motor driving the drum with low voltage, modifications are made in the electronic card that controls the operation of the motor and the motor is enabled to operate with low voltage. However in this case the electric motor can be strained while rotating the drum even if the amount of laundry loaded in the drum stays within the normal limits and continues to be heated until the thermal element cuts off the current.
In the Great Britain Patent Application no. GB2183809 , in a washing machine, a motor safety device switches off the drive motor of the washing machine drum in the event of a failure affecting the motor. In order to protect the laundry in the drum against overheating, after the motor and thus the drum stop operating, an electrical switching element controls a protective switch arranged in the current circuit of the drying heater which switches off the current of the heater.
In the European Patent no. EP 0312072 , a safety device for a laundry drier is adapted to cut the electric power supply to the machine in case of insufficient or totally absent drying air circulation due to clogging of the filter and/or stoppage of the electric motor of the blower and the drum caused by failure or functional defects of the motor.
The aim of the present invention is the realization of a washer/dryer, wherein the electric motor actuating the drum is prevented from malfunction resulting from low network voltage and/or overloading of the drum and a control method thereof.
The washer/dryer realized in order to attain the aim of the present invention is explicated in the first claim and the other features are explicated in the respective claims.
In the washer/dryer and the control method, the washer/dryer is operated after the laundry is loaded into the drum and as the drum spins the laundry inside making a rotating movement, a fan driven by an electric motor blows air over the heater and the heated air is blown over the laundry.
When the electric motor driving the fan is strained in rotating or not rotating at all, the rotation of the fan driven by the motor also slows down or it does not rotate at all, and the temperature in the vicinity of the heater rises quickly since inadequate or no air passes over the heater.
A heat sensor detects the rise in the temperature of the heater and sends a signal to the control card that controls the operation of the motor and the control card immediately cuts off the current to the electric motor. Although the thermal protector provides safeguarding against overheating, the thermal protector is not awaited to cut off the current and consequently the overheating of the motor windings leading to a reduction of the motor life is prevented.
In this embodiment, after the electric motor is stopped, the voltage from the network should be checked whether it is low or not. If the voltage is low, then it is determined that the reason for the motor strain is due to low voltage, if not then the electric motor is strained from another cause. In this case there is a stand by period until the voltage rises and the user is warned by a low voltage warning unit.
In another embodiment of the present invention, the electric motor driving the fan is also utilized in rotating the drum.
In this embodiment, when the electric motor is stopped, if the network voltage is detected not to be low, then it is determined that the drum of the washer/dryer is overloaded since the electric motor that rotates the fan also rotates the drum and a loading warning unit warns the user in an audio and/or visual manner to reduce the laundry load. The user can restart the stopped washer/dryer after reducing the laundry load by pushing the start button.
In regions where there is frequent irregularities in the network voltage, even though the amount of laundry loaded in the drum of the washer/dryer is not much, the vicinity of the heater is heated since the electric motor is strained in rotating the fan and the control card stops the electric motor before the thermal protector cuts off the current, warning the user to reduce the load. Thus, the user uses the washer/dryer safely by loading with a lower than normal load, e.g. if the need arises, to use it in low network voltage.
The washer/dryer realized in order to attain the aim of the present invention is illustrated in the attached figures, where:

Figure 1 - is the schematic view of a washer/dryer.
Figure 2 - is the flow chart of a washer/dryer control method Elements shown in the figures are numbered as follows:

1.

Washer/dryer

2.

Drum

3.

Electric motor

4.

Fan

5.

Heater

6.

Heat sensor

7.

Thermal protector

8.

Start button

9.

Control card

10.

Low voltage warning unit

11.

Load warning unit

The washer/dryer (1) comprises a drum (2) wherein laundry (L) is loaded, a fan (4) for blowing air on the laundry to be dried, an electric motor (3) driving the fan (4), a heater (5) providing heating of the drying air blown over the laundry (L), a heat sensor (6) positioned near the heater (5) for detecting the temperature in the vicinity of the heater (5), a thermal protector (7) that cuts off the current (I) to the electric motor (3) in the event that the electric motor (3) is overheated due to over straining, a start button (8) providing the user to start the drying process and a control card (9) that controls the operation.
If the temperature (T) detected by the heat sensor (6) in the vicinity of the heater (5) exceeds (T > Tmax) a predetermined limit temperature (Tmax), the control card (9) determines that the fan (4) driven by the electric motor (3) is not rotated at the required speed and the temperature (T) in the vicinity of the heater (5) has increased due to insufficient amount of air blown over the heater (5) and the current (I) delivered to the electric motor (3) is cut off.
In the embodiment of the present invention, the current (I) delivered to the electric motor (3) strained in rotating the fan (4) and thus starting to be heated, is cut off by the control card (9) before the thermal protector (7), without waiting for the thermal protector (7) to stop it.
In this embodiment, after the current (I) delivered to the electric motor (3) is cut off by the control card (9), the reason for the electric motor (3) strain is investigated and first of all the network voltage (V) is controlled for whether or not it is lower (V < Vd ?) than a limit low voltage value (Vd) where the electric motor (3) can operate without a problem.
If the control card (9) detects that the network voltage is low (V < Vd), then it is determined that this factor is the reason for the electric motor (3) strain and the electric motor (3) is operated after the voltage (V) rises. If the network voltage is not low (V > Vd), then it is inferred that the strain of the electric motor (3) is due to another factor.
The washer/dryer (1) comprises a low voltage warning unit (10) that warns the user in case of low voltage values (V < Vd). If the electric motor (3) is strained or stopped due to low voltage (V < Vd), the user is warned by means of the low voltage warning unit (10) while awaiting for the voltage (V) to rise.
In another embodiment of the present invention, the electric motor (3) is utilized for actuating both the fan (4) and the drum (2).
In this embodiment, since the electric motor (3) actuates both the fan (4) and the drum (2), if the control card (9) detects that the network voltage is not low (V > Vd), t hen it is determined that the amount of laundry (L) loaded in the drum (2) is more than the operating conditions of the electric motor (3).
The washer/dryer (1) comprises a load warning unit (11) that warns the user to reduce the load (L) in an audio and/or visual manner when the load (L) is detected to be excessive. The user is warned by the load warning unit (11) in an audio and/or visual manner to reduce the load (L) and after the user reduces the load (L), the washer/dryer (1) can be restarted by pushing the start button (8).
In the embodiment wherein the fan (4) and the drum (2) are driven by the same electric motor (3), the washer/dryer (1) control method comprises the following steps:

The heater (5) and the electric motor (3) are operated according to the drying algorithm (100).
The temperature (T) in the vicinity of the heater (5) is measured by the heat sensor (6) (101).
Controlling whether or not the temperature (T) in the vicinity of the heater (5) has exceeded the limit temperature (Tmax) (102).
If T < Tmax, then the washer/dryer (1) continues its normal cycle.
If T > Tmax, the control card cuts off the current (I) delivered to the electric motor (3) from the network without waiting for the thermal protector (7) to cut off the current (I) (103).
Controlling whether or not the network voltage (V) is low (V < Vd ?) (104)
If the voltage (V) is not low (V > Vd), then it is determined that drum (2) load (L) is greater that operating conditions (105).
Giving audio and/or visual warning for reducing the load (L) by the load warning unit (11) (106).
Going back to the step (100) where the heater (5) and the electric motor (3) are operated after the load (L) is reduced.
If the voltage (V) is low (V < Vd), then it is determined that this factor is the reason for the electric motor (3) strain and warning is given by the low voltage warning unit (10) (107).
Waiting until the voltage (V) rises (108).
Going back to the step (100) where the heater (5) and the electric motor (3) are operated.

In the embodiment of the present invention, in cases where the network voltage (V) is irregular, e.g. when the network voltage (V) frequently drops to values nearing (V ≈ Vd) that are above (V > Vd) the limit voltage (Vd), the electric motor (3) is strained in rotating the fan (4) and if the temperature (T) in the vicinity of the heater (5) exceeds the value Tmax, then the electric motor (3) is stopped. In this case when the voltage (V) is greater (V> Vd) than the limit value (Vd), the control card (9) determines that the load (L) is greater than the operational conditions because of the algorithm requirement even though the load (L) is normal and the load warning unit (11) is energized to warn the user for reducing the load (L). Consequently in regions where the voltage (V) is always low, the user is provided with the opportunity to operate the washer/dryer (1) without problems with a little less than normal load (L).
The user is informed about the reason for the electric motor (3) strain by way of the load warning unit (11) and/or the low voltage warning unit (10) and thus the washer/ dryer (1) can be utilized safely.

Claims

A washer/dryer (1) comprising a drum (2) into which the laundry (L) is loaded, a fan (4) for blowing air onto the laundry to be dried, an electric motor (3) driving the fan (4), and a heater (5) providing heating of the drying air blown over the laundry, and a control card (9) that provides the current (I) delivered to the electric motor (3) to be cut off if a heat sensor (6) positioned near the heater (5) detects that the temperature (T) in the vicinity of the heater (5) exceeds a limit temperature (T > Tmax) and characterized in that the control card (9) is configured to control whether or not the network voltage (V) is lower (V < Vd) than a limit low voltage value (Vd) after the current (I) delivered to the electric motor (3) has been cut off by the control card (9).
A washer/dryer (1) as in Claim 1, characterized by an electric motor (3) that actuates both the fan (4) and the drum (2).
A washer/dryer (1) as in Claim 1 or 2, characterized by a low voltage warning unit (10) that warns the user if the network voltage (V) is detected to be low (V < Vd) after the current (I) delivered to the electric motor (3) is cut off by the control card (9).
A washer/dryer (1) as in Claim 2, characterized by a load warning unit (11) that warns the user to reduce the load (L) if the network voltage (V) is detected not to be low (V > Vd) after the current (I) delivered to the electric motor (3) is cut off by the control card (9).
For a washer/dryer (1) as in any one of the above claims, a control method comprising the following steps : Operating the heater (5) and the electric motor (3) according to the drying algorithm (100) ; measuring the temperature (T) in the vicinity of the heater (5) by the heat sensor (6) (101); controlling whether or not the temperature (T) in the vicinity of the heater (5) exceeds the limit temperature (Tmax) (102); if T < Tmax, then the washer/dryer (1) continues its normal cycle; if T > Tmax, then cutting off the current (I) delivered to the electric motor (3) from the network by the control card (9) (103).
For a washer/dryer (1) as in Claim 4, a control method comprising the following steps : operating the heater (5) and the electric motor (3) according to the drying algorithm (100); measuring the temperature (T) of the heater (5) by the heat sensor (6) (101); controlling whether or not the temperature (T) of the heater (5) has exceeded the limit temperature (Tmax) (102); if T < Tmax, then the washer/ dryer (1) continues its normal cycle; if T > Tmax, then cutting off the current (I) delivered to the electric motor (3) from the network by the control card (9) (103); controlling whether or not the network voltage (V) is low (V < Vd ?) (104); if the voltage (V) is not low (V > Vd), then it is determined that the drum (2) load (L) is greater than operating conditions (105); giving audio and/or visual warning for reducing the load (L) (106).
For a washer/dryer (1) as in Claim 3, a control method comprising the following steps : operating the heater (5) and the electric motor (3) according to the drying algorithm (100); measuring the temperature (T) of the heater (5) by the heat sensor (101); controlling whether or not the temperature (T) of the heater (5) has exceeded the limit temperature (Tmax) (102); if T < Tmax, then the washer/dryer (1) continues its normal cycle; if T > Tmax, then cutting off the current (I) delivered to the electric motor (3) from the network by the control card (9) (103); controlling whether or not the network voltage (V) is low (V < Vd ?) (104); if the voltage (V) is low (V < Vd), then it is determined that this factor is the reason for the electric motor (3) strain and warning is given by the low voltage warning unit (10) (107); waiting until the voltage (V) rises (108).