Thermocouples can be connected in series/parallel to obtain greater sensitivity called as

A thermopile is an electronic device that converts thermal energy into electrical energy.
It is composed of several thermocouples connected usually in series or less commonly, in parallel.
Thermopiles are used for contactless temperature sensing.
The function of a thermopile is to transfer the heat radiation emitted from the object to a voltage output.
The output is in the range of tens or hundreds of millivolts.

The miniature circuit breaker (MCB) with Class D trip characteristics trips instantaneously when the current flowing through it reaches ____ the rated current.

Class B trip curve :
The MCB with class B trip characteristics trips instantaneously when the current flowing through it reaches between 3 to 5 times rated current. These MCBs are suitable for cable protection.

Class C trip curve:
MCB with class C trip characteristics trips instantaneously when the current flowing through it reaches between 5 to 10 times the rated current. Suitable Domestic and residential applications and electromagnetic starting loads with medium starting currents.

Class D trip curve:
MCB with class D trip characteristics trips instantaneously when the current flowing through it reaches between Above 10 (excluding 10) to 20 times the rated current. Suitable for inductive and motor loads with high starting currents.

Class K trip curve:
MCB with class K trip characteristics trips instantaneously when the current flowing through it reaches between 8 to 12 times the rated current. Suitable for inductive and motor loads with high inrush currents.

The expression for voltage regulation of a short transmission line for leading power factor is given by: ____, where, 'I' is the line current, 'V_r' is the receiving end voltage, 'R' is the line resitance and 'X' is the line reactance.

For lagging power factor = (IR*cosφ + IXsinφ)/V_r
For leading power factor = (IR*cosφ - IXsinφ)/V_r
Zero voltage regulation occurs on leading power factor only.

A three-phase 400 V, 6-pole, 50 Hz squirrel-cage induction motor is running at a slip of 5%. The speed of rotor with respect to stator magnetic field and speed of the stator magnetic field with respect to rotor magnetic field are

Slip, s = (Ns - Nr)/Ns
Ns = 120f/P
0.05 = (1000 - Nr)/1000
Nr = 950 rpm
Speed of rotor with respect to stator magnetic field = 950 - 1000 = -50 rpm

Speed of the stator magnetic field with respect to stator core = 0
Speed of the rotor magnetic field with respect to rotor = sNs
Speed of the stator magnetic field with respect to rotor magnetic field = 0
Speed of the rotor magnetic field with respect to stator core = Ns

સોહેલ ખાન : મલાયકા અરોર :: સૈફ અલી ખાન : ??

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