Engineering Q&A
Temperature controller using SCR
in Power Electronics by

1 Answer

0 like 0 dislike

Temperature controller using SCR

image

The temperature control circuit is used to regulate the temperature. Figure shows the temperature control circuit using thermostat as temperature detector and SCR as a switching device. The mercury in glass thermostat is extremely sensitive temperature measuring instrument which is capable of sensing changes in temperature of the order of 0.1°C.

Working: 

Mode I: When the temperature is less than the desired value, the mercury in the glass thermostat is not able to short the electrodes A & B. Therefore the SCR receives the gate signal in both the half cycles & it will be triggered. Hence the heater will be connected to AC source in respective half-cycles. Thus heating is continued and temperature increases to desired level.

Mode II: As the temperature increases, the mercury level increases and when it reaches the desired value, the electrode A and B are short circuited through mercury. This will short circuit the gate to cathode, hence no trigger pulse can be received by SCR. Hence it is not turned-on in the next half-cycle & maintained off. Thus the heater gets disconnected and will remain disconnected from the circuit. The heating then stops and temperature is not allowed to rise beyond desired level. After some time when temperature falls to certain level and mercury switch gets opened, i.e the gate-cathode short-circuit is opened, the pulse is provided to SCR in each half-cycle and heater gets connected to source to produce heat and raise the temperature.

by

Related questions

1 answer
asked Oct 13, 2019 in Power Electronics by anonymous1 | 35 views
1 answer
1 answer
1 answer
asked Dec 9, 2017 in Power Electronics by Quiz | 54 views
2 answers
0 answers
asked Mar 19, 2018 in Thyristor by Quiz | 41 views
1 answer
asked Mar 19, 2018 in Thyristor by Quiz | 93 views
0 answers
asked Mar 15, 2018 in Electronics Engineering by Quiz | 22 views
Welcome to electronics2electrical.com, where students and teachers can ask and answer any question. Get help and answers to any engineering problem including Electrical, electronics, mechanical, telecommunication, instrumentation, computer, mathematics, physics etc. Get answers to questions. Help is always 100% free!

Most popular tags

power motor dc circuit transformer voltage current system used phase resistance factor ac load synchronous induction energy electric generator electrical series frequency capacitor between plant line speed transmission use meter type advantages difference single mosfet control function instrument magnetic amplifier problem high diode bjt machine unit source motors and diagram winding shunt field parallel define electricity torque value maximum relay arduino supply time digital armature types applications thyristor working transformers wave on flow operation three coil material instruments state ratio signal emf effect formula efficiency theorem method disadvantages starting microprocessor test operating direction controlled different logic transistor single-phase network scr loss temperature connected rc law force inductance compare measure station wire low conductor principle wattmeter full characteristics measuring constant measurement breaker losses device converter bridge linear materials nuclear matrix flux drive resistivity of machines angle switch free rectifier protection core battery solar gain thermal loop generators open circuits negative analog number lines friction reactance short gate pole inverter the conservation diesel iron resistors capacitance engineering basic direct main electronic electronics a steam induced relays hysteresis universal transducer computer feedback using range distribution work secondary igbt algebra pmmc plants factors capacitors dielectric controller regulation systems design air fault components rotor cable starter oscillator eddy alternator application semiconductor ammeter rl average forces damping rlc connection zener electromagnetic biasing minimum insulation pressure balanced permanent moving errors running copper self impedance stability quality start ideal curve over commutation 3-phase arc permeability peak bias error fuzzy commutator conductors superposition density mechanical rotation construction measured electrons charge memory inductive transfer explain fuse methods off back is three-phase tariff locomotive installation welding heating rms surge rating generation potentiometer coupled shaded rate capacity storage adc excitation active two pure harmonics reluctance microcontroller voltmeter inductor internal 8085 cro reaction insulating overhead hydro resonance traction definition breakers earth neutral designed

9,174 questions

7,920 answers

152 comments

3,290 users

9,174 questions
7,920 answers
152 comments
3,290 users