Monday, January 3, 2011

Weak current College】 【】 thermostat knowledge.

<br> Thermostat knowledge <br> Temperature controller is on the air conditioning room temperature control of electrical switchgear. Temperature controller for the control of air conditioning in room temperature range generally 18 ℃ -28 ℃. Window type air conditioner temperature controller is used to .pressure principle to promote contacts and broken. Its structure consists of corrugated pipes, sensor (test tube), eccentric, micro switch, etc. form a sealed sensor system and a dynamic system to transmit signals. <br> Control method is generally divided into .two types; one is borne by the temperature change of cooling object to control the use of vapour pressure temperature controller, another by the temperature difference of cooling object changes to the control, the use of electronic temperature controller. Thermostat is divided into: <br .> Vapour pressure: mechanical thermostats, liquid expansion of the thermostat, gas adsorption temperature controller, metal expansion of the thermostat. <br> Where vapour pressure type thermostat is divided into: inflatable type, liquid-gas hybrid and filled with fluid. Household air .conditioning mechanic in this type of thermostat. <br> Electronic: resistance thermostat and Thermocouple type thermostat. <br> Circuit system roles: <br> Air conditioning circuit system's role is to control the air conditioning running normal and multifunctional, protect the compressor and .the fan motor running. Circuit system components include: temperature controller, thermal protectors, master switch, running capacitor, the fan motor running capacitors, etc. to be fixed in the control box. Temperature controller role just control the starting and stopping the compressor. .<br> Working principle <br> Vapor pressure <br> Bellows movements on the elastic spring, spring is determined by the control knob on the control of the capillary on air conditioners indoor inhalation of air diffusers, on indoor cycle return air temperature reacts. .When the temperature rose to a set temperature, capillary and bellows in thermal expansion of gas, the corrugated pipe elongation and to overcome the spring stretch through the switch contact, refrigerant compressor operation system, until the temperature has dropped to a set temperature, the temperature .sensor gas shrinkage, together with the spring bellows shrinkage, will switch on the fracture location so that the compressor motor circuit cut off. This repeated actions, so as to achieve the purpose of controlling the room temperature. <br> Electronic temperature controller <br .> Electronic temperature controller (resistive) is a method of resistance temperature sensor to measure, generally use Platinum wire, copper wire, wire and semiconductor (thermistor) is a thermometric resistance, the resistors have excellent indeed. Most of the sensor conditioner with thermistor- .type. <br> Thermistor-type temperature controller is based on the principle of the Wheatstone bridge. In BD ends plugged E, under Kirchhoff, when bridge resistance R1 × R4 = R2 × R3, two points A and C are equal, the potential .output of the A and C there is no current flowing between, thermistor resistance R1 sizes with ambient temperature rise or drop of the alter, and destruction of the balance between the output current AC. Therefore, the thermostat, you can very easily by selecting the .appropriate thermistor to change temperature adjustment range and working temperature. <br>.

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