Recent questions tagged thermal

Description : Explain the thermal triggering method of SCR. Enlist different triggering methods of SCR.

Last Answer : Types of Triggering: 1) Forward voltage triggering 2) Thermal triggering (Temperature triggering) 3) Radiation triggering (Light triggering) 4) dv/dt triggering 5) Gate triggering ... generated leakage current increases. This current gets multiplied internally and thyristor is turned on. 

Description : Define thermal runaway.

Last Answer : Thermal runaway  The problem with increasing temperature causing increasing collector current is that more current increase the power dissipated by the transistor which, in turn, increases its temperature ... self-reinforcing cycle is known as thermal runaway, which may destroy the transistor. 

Description : Classify condensers used in thermal power station. Explain each type in brief. 

Last Answer : Types of condenser: Classification: 1. Jet Condenser (Mixing Type) 2. Surface condenser (non Mixing type)  Explanation:-   1. Jet Condenser (Mixing Type) In Jet condenser the steam ... there in no direct contact between the steam and cooling water. This condensate is reused in boiler. 

Description : "Efficiency of thermal power station is low". — Justify. 

Last Answer : Justification: Efficiency of thermal power station is low":- Overall efficiency of T.P.P depends upon efficiency of boiler, turbine and alternator. The heat produced due to combustion of coal ... losses in thermal power plant is 71%, So efficiency of thermal power plant is less about 29% 

Description : State advantages of Pulverized coal w.r.t. thermal power plant. 

Last Answer : Advantages of Pulverized coal w.r.t. thermal power plant.  1. Due to pulvarization amount of fuel required to produce same amount of heat reduces. 2. Time required for combution reduces ... of air and thorough mixing of air and fuel, very high-combustion temperatures can be attained.

Description : State the function of super heater of a thermal power plant. 

Last Answer : Function of Super heater: -  Its function is to increase the temperature of steam by absorbing heat from exhausted hot flue gases.

Description : Describe thermal runaway of transistor and explain how it can be avoided.

Last Answer : Concept of thermal runaway:  1.We know that  IC = β IB + (1+ β) ICO  Where ICO is the leakage current and ICO is strongly dependent on temperature. 2. Leakage current approximately doubles for ...   Thermal runaway can be avoided by : 1) Using stabilization circuitry 2) Heat sink 

Description : State the function of cooling tower and condenser in thermal power station.

Last Answer : 1. Condenser:   Function of condenser is to convert exhaust steam again into water by reducing its temperature with the help of cold water. Also it reduces back pressure of steam turbine 2 ... tower : The function of cooling tower is to reduce the temperature of water coming from condenser.

Description : Write any four advantages and four disadvantages of thermal power plant.

Last Answer : .embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

Description : Explain ash disposal and dust collection in a thermal power plant.

Last Answer : Ash disposal:-  Various methods of disposal of ash are:  Mechanical handling system.  Pneumatic system. Hydraulic system  Steam jet system  Commonly used ash handling ... be done either manually or automatically.  This removed fly ash is collected in separate container

Description : State any four factors governing Selection of site for thermal power station. 

Last Answer : Following Factors are to be considered:- 1. It should locate near coal mine. 2. Sufficient quantity of water should be available. 3. Sufficient large space should be available. 4. It should be located ... laws of the land and the town planning. 14. The interests of national defense must be served.

Description : The overall efficiency of Thermal Power Plant is equal to _______________ .  (A) Regenerative Cycle Efficiency (B) Renkine Cycle Efficiency (C) Carnot cycle efficiency (D) None of the above

Last Answer : The overall efficiency of Thermal Power Plant is equal to Regenerative Cycle Efficiency. 

Description : In a thermal power plant, ash is collected in

Last Answer : In a thermal power plant, ash is collected in hoppers or bunkers

Description : The unit heat rate characteristic of a thermal power unit shows :  (A) Heat input per kWh of output versus the megawatt output of unit  (B) Heat input per kW of output versus the megawatt output ... hour output of unit  (D) Heat input per kW of output versus the megawatt hour output of unit

Last Answer : The unit heat rate characteristic of a thermal power unit shows : Heat input per kWh of output versus the megawatt output of unit 

Last Answer : Thermal overload relays are used to protect the motor against overcurrent due to heavy loads.

Last Answer : Thermal circuit breaker has delayed trip action.

Last Answer : A thermal protection switch can protect against overload.