WorksheetsPE Unit 2
Total questions: 20
Worksheet time: 11mins
A single-phase symmetrical semi-converter employs
One SCR and one diode in each leg
Two SCRs and two diodes in each leg
Two SCRs in each leg
Two diodes in each leg
A single-phase asymmetrical semi-converter employs
One SCR and one diode in each leg
Two SCRs in one leg and two diodes in the other
Two SCRs in both the legs
Two diodes in both the legs
In the given circuit, from ωt = π to π+α and continuous load current configuration
T1 and T2 conduct
T2 and D1 conduct
T1 and D2 conduct
T1 and D1 conduct
A single-phase semi-converter is connected to a 230 V source and is feeding a load R = 10 Ω in series with a large inductance that makes the load current ripple free. Find the average output current for α = 45°.
14 A
17 A
10 A
0 A
A fully controlled converter uses
Thyristors only
Diodes only
Both diodes and thyristors
None of the mentioned
A single phase full-converter using R load is a _________ quadrant converter and that using an RL load without FD is a __________ quadrant converter
One, one
Two, one
One, two
Two, two
With respect to the given circuit, from ωt = 0 to α, ____ thyristor(s) block the forward voltage
T1 and T2
T2
T3 and T4
T4
A single-phase full controlled converted with RLE load will act like a line-commutated inverter when the firing angle α
α > 180°
α = 90°
α < 90°
α > 90°
A single-phase full converter bridge, is connected to a RLE load. The source has a rms voltage of 230 V and the average load current is 10 A. Find the firing angle for which the power flows from AC source to the DC load. Consider E = 120 V, R = 0.4 Ω.
26.4°
53.2°
142°
39°
For the given converter configuration, find the expression for the average value of voltage across the resister R with Vs = Vm sinωt and firing angle = α.
Vm/π cosα
2Vm/π cosα
Vm/π (1+cosα)
2Vm/π (1+cosα)
Name the given circuit.
Full controlled, bridge converter
Bridge type semi-converter
Full controlled, semi converter
Half controlled, full converter
In three phase semi-converter, each SCR and diode conduct for
60° and 120° respectively
120° and 60° respectively
60°
120°
In a 3-phase semi-converter, for firing angle less than 60° the freewheeling diode conducts for
30°
60°
120°
0
For a three phase full controlled converter, with 3 thyristors in the upper or positive group and 3 thyristors in the lower or negative group, at any given time
One thyristor is conducting from each group
Two thyristors are conducting from each group
One thyristor is conducting from either of the groups
All 6 thyristors are conducting at a time
In case of a three phase full controlled converter with 6 SCRs, commutation occurs every
120°
180°
30°
60°
For a three-phase full controlled converter with R load, the average value of output voltage is zero for
α = 0°
α = 90°
α = 180°
It can never be zero
The commutation period when both incoming and outgoing SCRs are conducting due to source inductance is called as the
Overlap period
Conduction delay
One on one period
Distorting angle
If the commutation angle μ is equal to π, then the output voltage will be
Maximum
Zero
Depends on source inductance
Minimum
Dual converters provide
Two quadrant operation
Three quadrant operation
Four quadrant operation
None of the mentioned
In non-circulating current mode dual converters, the circulating current is avoided by
Connecting a series reactor
Maintaining α1 + α2 = 180°
Operating only one converter
Adding an extra SCR
