Question

A transformer has 500. primary turns and 10.0 secondary turns. (a) If Vp is 120.V(rms), what is Vs? If the secondary now has a resistive load of 10.0Ω, what is the current in the (b) secondary and (c) primary? (Hints: Input power equals the output power. Express power in terms of voltage and current, then use Faraday’s Law to relate voltage to number of turns and change of flux. If the primary and the secondary are connected via a closed loop core, the change of flux in both should be the same. Derive a relationship between the voltages, number of turns and currents for the primary and secondary.)

Answer #1

An ideal step-down transformer has a primary coil of 370 turns
and a secondary coil of 25 turns. Its primary coil is plugged into
an outlet with 115 V(AC), from which it draws an rms current of
0.69 A.
What is the voltage in the secondary coil?
Calculate the rms current in the secondary coil.
Assuming that the transformer secondary is driving a resistive
load, calculate the average power dissipated in the resistor.

a) An ideal step-down transformer has a primary coil of 400
turns and a secondary coil of 14 turns. Its primary coil is plugged
into an outlet with 240 V(AC), from which it draws an rms current
of 0.35 A. What is the voltage in the secondary coil?
b) Calculate the rms current in the secondary coil.
c) Assuming that the transformer secondary is driving a
resistive load, calculate the average power dissipated in the
resistor.

A transformer connected to a 120 −V ac line is to supply 12.0 VV
(rms) to a portable electronic device. The load resistance in the
secondary is 5.20 ΩΩ .
- What should the ratio of primary to secondary turns of the
transformer be, What rms current must the secondary supply?
- What average power is delivered to the load, What resistance
connected directly across the source line (which has a voltage of
120 −V) would draw the same power...

A transformer has 380 primary turns and 1140 secondary turns.
The input voltage is 120 V and the output current is 16.5A . Assume
100% efficiency.
A) What is the output voltage?
B) What is the input current?

A transformer has a primary-to-secondary turns ratio of 100:1.
The voltage on the primary side is 27.7 kv.a.c. at 60.0 Hz ( assume
60.0 Hz when treating electric power topics). A load is connected
across the secondary winding. Assume that the transformer is
ideal.
(a) Suppose that the electric utility supplied 27.7 kv.d.c.
rather than 27.7 kv.a.c. How much power would the transformer’s
secondary winding deliver to the load in this case?
(b). The transformer’s primary winding is supplied by...

A single-phase transformer has 2400 turns on the primary and 600
turns on the secondary. Its no-load current is 4A at a power factor
of 0.25 lagging. Assuming the volt drop in the windings is
negligible, calculate the primary current and power factor when the
secondary current is 80A at a power factor of 0.8 lagging.

6.
A transformer has an input voltage of 120 V(rms) AC with an output
of 12,000 V(rms) AC . The number of wire turns in the primary is
75. An output power of 245 W is required. Assume the transformer is
approximately 100% efficient. Find the
a. Number of wire turns needed on the output side.
b. input current
c. Output current

An ideal transformer has 100 turns on its primary coil and 200
turns on its secondary coil. If 120 V at 2.0 A is applied to the
primary,
(a) What voltage is present in the secondary?
(b) What current is present in the secondary?
(c) What is the output power?
(d) Is this a step-up or step-down transformer?
(e) Is the input power the same, larger or smaller than the
output power?

The primary coil of a transformer has N1 = 340 turns, and the
secondary coil has N2 = 2 190 turns. If the input voltage across
the primary coil is Δv(t) = 170 cos ωt, where Δv is in volts and t
is in seconds, what rms voltage is developed across the secondary
coil?

Problem 1: Consider a transformer with a turns ratio of
4000/120, with a primary coil resistance R1 = 1.6 (?), a secondary
coil resistance of R2 = 1.44 (m?), leakage flux that corresponds to
the inductance L1 = 21 (mH), and inductance L2 = 19 (?H), and a
realistic core characterized by the core resistance Rc = 160 (k?)
and the magnetizing inductance Lm = 450 (H). The low-voltage side
of the transformer is at 60 (Hz), and V2 =...

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