**Last Answer :** An ideal transformer will have maximum efficiency at a load such that copper loss equal to iron loss.

**Description :** For a transformer, operating at constant load current, maximum efficiency will occur at?

**Last Answer :** For a transformer, operating at constant load current, maximum efficiency will occur at unity power factor.

**Last Answer :** D.C. generators are normally designed for maximum efficiency around full-load.

**Last Answer :** The condition for maximum efficiency for a D.C. generator is variable losses equal to constant losses.

**Last Answer :** Generators for peak load plants are usually designed for maximum efficiency at 50 to 75 percent full load.

**Description :** A transformer operates 24 hours day at full -load. It's full -load efficiency is : (A) equal all day efficiency (B) more than all -day efficiency (C) less than all -day efficiency (D) equal to maximum efficiency

**Last Answer :** A transformer operates 24 hours day at full -load. It's full -load efficiency is : equal all day efficiency

**Last Answer :** The efficiency of transformer is Greater than electrical Machine because there is no rotational losses in transformer and there is no air gap losses in transformer so losses is less in transformer compare to electrical machine so efficiency is higher in case of transformer.

**Description :** If a transformer is continuously operated the maximum temperature rise will occur in?

**Last Answer :** If a transformer is continuously operated the maximum temperature rise will occur in windings.

**Description :** The maximum load that a power transformer can carry is limited by its?

**Last Answer :** The maximum load that a power transformer can carry is limited by its voltage ratio.

**Description :** State why a transformer always have an efficiency of more than 90%.

**Last Answer :** As transformer is static device with no moving parts, the losses due to friction & windage are completely absent. Hence transformer has efficiency of more than 90%.

**Last Answer :** The efficiency of a power transformer is of the order of 98 percent.

**Description :** The efficiency of a transformer, under heavy loads, is comparatively low because?

**Last Answer :** The efficiency of a transformer, under heavy loads, is comparatively low because copper loss becomes high in proportion to the output.

**Description :** Define : i) Maximum Value ii) RMS Value of ac supply

**Last Answer :** i) Maximum Value :- The maximum or peak value attained by an alternating quantity during positive or negative half cycle, is called maximum value or peak value. ii) RMS Value of ac ... as produced by the alternating current when flowing through the same resistance and for the same time.

**Description :** Define the following terms: 1) Virtual height 2) Actual height 3) Critical frequency. 4) Maximum usable frequency.

**Last Answer :** 1) Virtual height:- The incident and refracted rays follow paths that are exactly the same as they have been if reflection had taken place from a surface located at a greater height, called ... angle of incidence is other than the normal is known as maximum unstable frequency. MUF= fc secθ

**Description :** Maximum Power Transfer Theorem 1

**Last Answer :** Maximum Power Transfer Theorem 1

**Description :** State maximum power transfer theorem for DC circuit.

**Last Answer :** Maximum power transfer theorem for DC circuit: The maximum power transfer theorem states that the source or a network transfers maximum power to load only when the load resistance is equal ... removed (disconnected) ii) All internal independent sources are replaced by their internal resistances.

**Description :** An independent voltage source in series with an impedance ZS=R+jXS delivers a maximum average power to a load impedance ZL when A) ZL = R B) ZL = jXS C) ZL = R-jXS D) ZL = R+jXS

**Last Answer :** An independent voltage source in series with an impedance ZS=R+jXS delivers a maximum average power to a load impedance ZL when ZL = R-jXS

**Description :** method for improving string efficiency

**Last Answer :** The Methods of Improving String Efficiency:- 1) By reducing value of ‘m’ or (‘k’) by using longer cross arm. 2) By Making of ‘m’ or (‘k’) equal to zero 3) By grading Insulator. 4) By Using guard ring.

**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 :** A certain power MOSFET has a maximum junction temperature specification of 1500o C, a junction-to-case thermal resistance of 1.00 C/W, and a junction-to ambient thermal resistance of 600 C/W. If the ambient temperature is 300o C ... the device will be A) 1.52 W B) 1.72 W C) 1.92W D) 2.00 W

**Last Answer :** A certain power MOSFET has a maximum junction temperature specification of 1500o C, a junction-to-case thermal resistance of 1.00 C/W, and a junction-to ambient thermal resistance of ... 300o C, then the maximum allowable power dissipation in the device will be 2.00 W

**Description :** The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and quadrature-axis reactance, 0.5 pu, and input voltage, 1.0 pu is (A) 0.25 pu (B) 0.5 pu (C) 1.0 pu (D) 1.5 pu

**Last Answer :** The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and quadrature-axis reactance, 0.5 pu, and input voltage, 1.0 pu is 0.5 pu

**Description :** The maximum torque of d.c. motors is limited by?

**Last Answer :** The maximum torque of d.c. motors is limited by commutation.

**Description :** For maximum transfer of power, internal resistance of the source should be?

**Last Answer :** For maximum transfer of power, internal resistance of the source should be equal to load resistance.

**Description :** "Maximum power output is obtained from a network when the load resistance is equal to the output resistance of the network as seen from the terminals of the load". The above statement is associated with?

**Last Answer :** "Maximum power output is obtained from a network when the load resistance is equal to the output resistance of the network as seen from the terminals of the load". The above statement is associated with Maximum power transfer theorem.

**Last Answer :** Series motor has got maximum self relieving property.

**Last Answer :** (b) Clostridium butylicum Lipase Removal of oil stains

**Last Answer :** The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5.

**Last Answer :** In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be more than full-load current.

**Last Answer :** In repulsion motor, maximum torque is developed when brush axis is at 45° electrical to the field axis.

**Description :** The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as?

**Last Answer :** The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as pull-in torque.

**Last Answer :** In a power plant if the maximum demand on the plant is equal to the plant capacity, then plant reserve capacity will be zero.

**Last Answer :** Maximum demand on a power plant is the greatest of all "short time interval averaged" demand during a period.

**Last Answer :** More than 100%

**Description :** What is the maximum value of power factor?

**Last Answer :** 1 is the maximum value of power factor.

**Description :** In which fault the maximum short circuit current occurs?

**Last Answer :** In three phase bolted fault the maximum short circuit occurs.

**Description :** What is the maximum value of torque angle in synchronous motor?

**Last Answer :** The maximum value of torque angle in synchronous motor is 90 degrees electrical.

**Description :** The synchronous motor will develop maximum power when the load angle is?

**Last Answer :** The synchronous motor will develop maximum power when the load angle is 900.

**Description :** What is the maximum number of circuit breakers in a panel?

**Last Answer :** It depends on that which type of panel is this.

**Description :** At what power maximum efficiency of power transformer and distribution transformer is designed

**Last Answer :** Maximum efficiency of the transformer is attained at certain load factor (α) when core losses of transformer is equal to the copper losses. PCore loss = α ^2 X PCopper loss From the ... the day. Hence distribution transformers are designed to have maximum efficiency at 50% of the rated full load

**Description :** What is the condition for maximum efficiency of transformer?

**Last Answer :** When Iron losses is equal to copper losses.

**Description :** 42 The efficiency of a transformer will be maximum when A. copper losses = hysteresis losses B. Hysteresis losses = eddy current losses C. Eddy current losses = copper losses D. Copper losses = iron losses

**Last Answer :** D. Copper losses = iron losses

**Last Answer :** The maximum efficiency of a distribution transformer is at 50% full load.

**Description :** SEER: Seasonal Energy Efficiency Ratio (SEER)

**Last Answer :** SEER: Seasonal Energy Efficiency Ratio (SEER), is most commonly used to measure the efficiency of a central air conditioner. The higher the SEER, the more efficient the system OR It is the ... the ratio of total capacity to the total KW energy usage at specific humidity and temperature condition.

**Description :** Compare the salient features of LED and CFL based on: i] Lamp Efficiency ii] Life span

**Last Answer :** Parameter LED CFL Lamp Efficiency High (more than 70 lumen per watt) Comparatively less (50-60 lumen per watt) Life span (in working hours) 10000 3000

**Description :** Define PIV, TUF, ripple factor, efficiency of rectifier.

**Last Answer :** PIV: Peak Inverse Voltage (PIV) is defined as the maximum negative voltage which appears across non-conducting reverse biased diode. TUF : Transformer Utilization Factor (TUF) is defined as the ratio of DC output ... Efficiency of rectifier: η = DC output power/ AC input power = PLdc / Pac

**Description :** What is the efficiency of Class-B amplifier? A) 68.50% B) 78.50% C) 88.50% D) 98.50%

**Last Answer :** What is the efficiency of Class-B amplifier? A) 68.50% B) 78.50% C) 88.50% D) 98.50%

**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 :** The rankine cycle efficiency of steam power plant is (1) 60-80% (3) 30-45% (2) 45-80% (4) 20-30%

**Last Answer :** The rankine cycle efficiency of steam power plant is 30-45%

**Description :** Transmission efficiency of a transmission line increases with the

**Last Answer :** Transmission efficiency of a transmission line increases with the increase in power factor and voltage