Product Application
Washing machines have long been the most essential appliance in every household. Together with washers, clothes dryers are lifesavers for large family. To meet consumers’ expectations, modern washing machines offer a variety of soil level, spin speed, and tailored temperature options appropriate for different fabrics. Using the right temperature not only removes stain effectively when washing, but also protects clothes from overheat when drying. The temperature sensor in washing machines ensures accurate control of water temperature. In dryers, the sensor monitor the temperature of hot air in the drum or that of the exhausted air. THINKING offers a wide selection of standard and customizable NTC temperature sensors to help washers and dryers regulate the cycle.
The latest washers and dryers are designed with advanced features such as wireless connectivity and touch screens. The increased number of electronics makes associated circuit protection more complex and critical. In addition to temperature sensors mentioned above, THINKING offers a broad line of circuit protection components to protect the complex and sensitive circuits and recommends the following protection technologies for use in the applications.
NTC temperature sensors, also known as NTC temperature thermistors, are ideal for laundry temperature sensing and control. The recommended NTC temperature sensor, potted in a stainless steel case, is widely used in the extreme humid and corrosive environment. In addition, the NTC temperature sensor can withstand high voltage of 3750V AC, which assures the safety of long-term contact with water. The sensor usually comes with a RAST 2.5 or a 5.0 connector and is ready-to-use. For dryers, THINKING can also provide a flanged temperature sensor with wire that can be easily secured to the blower housing. Various electrical characteristics, structures, connectors, and cable lengths selections are available and customizable in accordance with customer’s needs. Specifications of temperature sensors for washing machines & dryers are as shown below:
• Typical operating temperature range: -10°C to +130°C
• Typical thermal time constant: 6 seconds or less
• Compliance with Glow Wire Testing and CTI (Comparative Tracking Index) according to IEC standards
• 0 PPM in electrical performance for more than 10 years
PTC Door Lock Mechanism: Modern washers or dryers usually equip with door lock to ensure user safety and to prevent the door from being opened while water is spraying. An innovative door interlock design incorporates PTC stone, also known as PTC heating element, to enable the interlocking mechanism. When the door is shut, the PTC stone in the door interlock assembly is electrified to heat up and bend the bimetallic strip, and which then activates other mechanical parts to keep the door locked.
THINKING’s Metal Oxide Varistors (MOV) protects power input from voltage surge and lightning events, and the NTC or PTC inrush current limiters effectively suppress inrush current. Components on the control board such as MOSFET and ICs are vulnerable, and they are also suggested to be guarded by MOV device. Some designers may choose TVS diodes to protect the circuits from the threat of voltage transients.
- Motors often risk from the damage of overload, stall, and overheating. Ceramic PTC thermistor is suggested to be installed to prevent the motors from the damage of overcurrent. An NTC temperature sensor is also recommended for monitoring the temperature to prevent the motor from overheat.
- Like the portable consumer devices, washing machines and tumble dryers equipped with touch screens and wireless connection systems are exposed to the threat from electrostatic discharge (ESD). A multilayer varistor or an ESD TVS diode is recommended to attenuate the energy.
The constant switching on and off actions of valve and pump may cause voltage transients and damage the vulnerable circuits. A transient voltage suppressor (TVS diode) can be employed to protect electronic components from induced voltage transients.
Clothes iron removes wrinkles and creases from clothes by heat. The heated surface of the iron presses the creased fabric and turns it into smooth, flat one. Modern clothes irons usually come with the function of releasing hot steam to relax the fiber in clothing and achieve better result. The innovation of ironing products focused on producing higher steam output to improve efficiency and convenience, for example, a steam generators iron with a detachable steam base that includes water tank and boiler. The water boiler produces pressurized steam that is sent through the steam hose to the soleplate fast and released under high pressure. The steam generator irons eliminate the hassle of adjusting temperature knobs and the wait for heat-up. The recommended NTC temperature sensor is potted in an aluminum cap and responds fast to thermal change (2.2 s). The sensing top is in direct contact with the soleplate and can withstand the heat up to 250°C.
