आधारभूत विद्युत् (Basic Electrical) – Basic Electrical Engineering MCQ

आधारभूत विद्युत् (Basic Electrical): प्रश्न र उत्तर

सही लागेको विकल्पमा थिच्नुहोस्। सही भए हरियो, गलत भए रातो देखिन्छ; ३ सेकेन्डपछि सही उत्तर र व्याख्या देखिन्छ।

सही: ० / ०

531. The cooling designation ONAN on a transformer nameplate means:

     कoil natural, air natural खoil normal, air normal गoil forced, air natural घoil natural, air forced
     💬 टिप्पणी / गल्ती रिपोर्ट (०)

     छलफल / प्रश्न उत्तरमा गल्ती छ

     पठाउनुहोस्

     टिप्पणी जाँचपछि मात्र देखिन्छ।

532. In the approximate equivalent circuit of a transformer, the shunt (parallel) branch represents:

     कthe copper losses of both windings खthe core (iron) loss and the magnetising current गthe leakage reactance of the windings घthe load impedance
     💬 टिप्पणी / गल्ती रिपोर्ट (०)

     छलफल / प्रश्न उत्तरमा गल्ती छ

     पठाउनुहोस्

     टिप्पणी जाँचपछि मात्र देखिन्छ।

533. On-load tap changers of power transformers are usually fitted on the high-voltage winding because:

     कit has fewer turns खthe low-voltage winding has no taps possible गit carries a smaller current, making switching easier घthe HV winding is always outermost and cannot be insulated
     💬 टिप्पणी / गल्ती रिपोर्ट (०)

     छलफल / प्रश्न उत्तरमा गल्ती छ

     पठाउनुहोस्

     टिप्पणी जाँचपछि मात्र देखिन्छ।

534. A three-phase transformer is connected star (primary) to delta (secondary) with a per-phase turns ratio of 10 : 1. With 11 kV line voltage on the primary, the secondary line voltage is about:

     क1100 V ख1905 V ग367 V घ635 V
     💬 टिप्पणी / गल्ती रिपोर्ट (०)

     छलफल / प्रश्न उत्तरमा गल्ती छ

     पठाउनुहोस्

     टिप्पणी जाँचपछि मात्र देखिन्छ।

535. In the transformer vector group Dyn11, the low-voltage side:

     कis delta-connected and lags the HV side by 30° खis star-connected and is in phase with the HV side गis star-connected with neutral brought out and leads the high-voltage side by 30° घis delta-connected and leads the HV side by 330°
     💬 टिप्पणी / गल्ती रिपोर्ट (०)

     छलफल / प्रश्न उत्तरमा गल्ती छ

     पठाउनुहोस्

     टिप्पणी जाँचपछि मात्र देखिन्छ।

536. The all-day efficiency of a distribution transformer is the ratio of:

     कoutput power to input power at full load खcopper loss to iron loss गrated kVA to average load घoutput energy (kWh) to input energy (kWh) over 24 hours
     💬 टिप्पणी / गल्ती रिपोर्ट (०)

     छलफल / प्रश्न उत्तरमा गल्ती छ

     पठाउनुहोस्

     टिप्पणी जाँचपछि मात्र देखिन्छ।

537. Regenerative braking of a three-phase induction motor occurs when:

     कtwo supply leads are interchanged while running खthe rotor is driven above synchronous speed, so the machine returns power to the supply गDC is injected into the stator घthe motor is disconnected and shorted through resistors
     💬 टिप्पणी / गल्ती रिपोर्ट (०)

     छलफल / प्रश्न उत्तरमा गल्ती छ

     पठाउनुहोस्

     टिप्पणी जाँचपछि मात्र देखिन्छ।

538. Rotor-resistance starters can be used only with slip-ring induction motors and, besides reducing starting current, they:

     कreduce the starting torque to zero खchange the synchronous speed गincrease the starting torque घimprove the full-load efficiency
     💬 टिप्पणी / गल्ती रिपोर्ट (०)

     छलफल / प्रश्न उत्तरमा गल्ती छ

     पठाउनुहोस्

     टिप्पणी जाँचपछि मात्र देखिन्छ।

539. The rotating magnetic field produced by a balanced three-phase stator winding has a constant magnitude equal to:

     कthe maximum flux of one phase ख1.5 times the maximum flux of one phase ग3 times the maximum flux of one phase घ√3 times the maximum flux of one phase
     💬 टिप्पणी / गल्ती रिपोर्ट (०)

     छलफल / प्रश्न उत्तरमा गल्ती छ

     पठाउनुहोस्

     टिप्पणी जाँचपछि मात्र देखिन्छ।

540. The synchronous speed of a 6-pole machine on a 60 Hz supply is:

     क1000 rpm ख1800 rpm ग1200 rpm घ3600 rpm
     💬 टिप्पणी / गल्ती रिपोर्ट (०)

     छलफल / प्रश्न उत्तरमा गल्ती छ

     पठाउनुहोस्

     टिप्पणी जाँचपछि मात्र देखिन्छ।