Test: Power Electronics - 2
25 Questions MCQ Test Power Electronics | Test: Power Electronics - 2
| 1 Crore+ students have signed up on EduRev. Have you? |
Natural commutation is possible only in ac circuits.
In a single phase full wave regulator feeding R-L load, the minimum firing angle can be zero.
Range of control of a is 0 ≤ a ≤ p.
An RC snubber circuit is used to protect a thyristor against :
Especially high 
during switching.
They are designated as T1 and T2 because diac can conduct in both directions.
A single phase semiconverter has a freewheeling diode. If the firing angle is a and the load is purely resistive, the periods of conduction and freewheeling respectively are
Freewheeling diode conducts only when load is inductive. If load is purely resistive free wheeling diode does not come into operation.
A dc separately excited motor has a constant field current. The armature is fed from a single phase supply through a semi-converter. When a = 0, speed is 600 rpm. If a = 90º, the speed is likely to be
Average output voltage is reduced to 50% if a = 90º. Hence speed is also reduced to 50%.
It can be turned on by positive gate pulse and turned off by negative gate pulse. It is minority carrier device. It can be manufactured in high current and high voltage ratings and its on state voltage drops is low.
A single phase step up cycloconverter changes 50 Hz to 100 Hz. Then one half wave of input will give rise to
Since output frequency is 2f, one half wave of input must equal one full wave of output.
Which of these triggering methods for series connected SCRs use LASCR in the gate circuit?
Optical triggering uses LASCR.
Two thyristors for each phase.
The average load current supplied by a thyristor depends on
The firing angle controls the period of conduction and hence average load current.
A dc chopper is feeding an RLE load. The maximum steady state ripple is
(Imax - Imin)max = 
.
In a 3 phase full wave regulator feeding a star connected resistance load the input voltage is 400 V line to line. The firing angle is 160º. The line to line output voltage would be
In a three-phase full wave regulator, output voltage is zero if a ≥ 150º.
A thyristor is reverse biased. A positive gate pulse is applied. The thyristor
Thyristor can turn on only when it is forward biased.
Series connection increases the voltage.
A single phase half wave controlled rectifier circuit has an R-L load. A freewheeling diode is also in the circuit. When freewheeling diode is conducting the SCR
Free wheeling diode is forward biased only when SCR is reverse biased.
It is a bilateral switch.
A 750 A circuit uses thyristor of current rating 175 A. If derating is 25%, the number of thyristors in parallel is
.
Assertion (A): An inverter does not require forced commutation
Reason (R): A series inverter is a forced commutation inverter.
Some inverters require forced commutation.
In a single phase full wave converter (M - 2 connection), the rms transformer voltage is 300 V across each half of secondary. The PIV for each thyristor is
PIV is twice the peak voltage across each half of secondary.
p = n = p = n.
Line commutated inverters are also used especially in HVDC.
In 180º mode of operation of a 3 phase bridge inverter, two thyristors conduct at one time.
In 180º mode three thyristors conduct simultaneously.
In a single phase full wave ac regulator the rms value of load current is 20 A load is purely resistive. Then
Each thyristor conducts for 50% of time.
A reactor is used in a dual converter operating in non-circulating current mode.
Reactor is used only for circulating current mode.
|
5 videos|39 docs|63 tests
|
|
Use Code STAYHOME200 and get INR 200 additional OFF
|
Use Coupon Code |
|
5 videos|39 docs|63 tests
|
Download free EduRev App
Related content with Test: Power Electronics - 2
|
|
|
|
Related tests with Test: Power Electronics - 2
|
|
|
|
|
|
© EduRev
|
Education Revolution
|
Follow Us
|
