A step-down transformer connected to a 120V electric generator has 30 loops on the primary for each loop in the secondary.
A) What is the voltage of the secondary?
B) If the transformer has a 90 A current in the primary, whats the current in the secondary?
C) What is the power input and output?
Please show equations as well, Thanks!
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Verified answer
The ratio of the number of turns is 1 over 30.
A) V2 = (N2 / N1) x V1 = 120 V / 30 = 4.0 V
B) I1V1 = I2V2 → I2 = (I1V1) / V2 = (90 A x 120 V) / 4.0 V = 2700 A
C) Power = Current x Voltage
Input Power = 90 A x 120 V = 10,800 W
Output Power = 2700 A x 4.0 V = 10,800 W
As you can see, voltage and current is transformed, but the power remains the same.
A Step Down Transformer
The voltage ratio is equal to the turns ratio (1/30).
120 x 1/30 = 4
The secondary voltage is 4 Volts.
If the transformer is 100% efficient, the power in is equal to the power out. Power watts = volts x amps.
120 x 90 = 10800 watts
The output current = watts/volts
10800/4 = 2700 amperes
The ratio of the number of turns is 1 over 30.
A) V2 = (N2 / N1) x V1 = 120 V / 30 = 4.0 V
B) I1V1 = I2V2 → I2 = (I1V1) / V2 = (90 A x 120 V) / 4.0 V = 2700 A
C) P = IV → P (input) = 90 A x 120 V = 11,000 W and P (output) = 2700 A x 4.0 V = 11,000 W
A. Four volts.
B. It can be as much as 30 x 90 = 2700 amperes. That is a LOT of current.
C. 10800 watts.
First response is correct except for a minor arithmetic error in part C.