Transformer Primary and secondary currents

Also, power = voltage x current.In summary, a single phase transformer with a rating of 120kVA and 1000 primary turns has 50 secondary turns. The rated primary current is 60A and the rated secondary current is 3A. The equation Vp/Vs = Np/Ns is not applicable for determining the rated currents. Instead, if the transformer is 100% efficient, then power supplied is equal to power delivered and can be calculated using the equation power = voltage x current.
  • #1
jitznerd
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Homework Statement



A single phase transformer has the following rating : 120kVA. 2000v/100v, 60 Hz with
1000 primary turns.

Determine:

a.Secondary turns
b.The rated primary and secondary currents

Homework Equations



Vp/Vs = Np/Ns

The Attempt at a Solution



a. I have used the Vp/Vs = Np/Ns to work out secondary turns
1000 x 100/2000 which gave me 50 secondary turns.

b. I arent sure if I have gone about this the right way and just wanted to check.

I divided the 120000VA by the primary voltage of 2000 to give me 60A. Is this correct to do this.
Then with my 60A I put that into the Vp/Vs = Ip/Is which gave me 3A as secondary current.

Could someone please tell me if this is correct thanks
 
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  • #2
Vp/Vs = Ip/Is is not the correct equation... have another look at it.
If the transformer is 100% efficient then power supplied = power delivered.
 
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FAQ: Transformer Primary and secondary currents

1. What is the difference between primary and secondary currents in a transformer?

The primary current is the current that flows through the primary winding of the transformer, which is connected to the power source. The secondary current is the current that flows through the secondary winding of the transformer, which is connected to the load.

2. How are primary and secondary currents related to each other in a transformer?

In an ideal transformer, the ratio of the primary current to the secondary current is equal to the ratio of the number of turns in the primary winding to the number of turns in the secondary winding. This is known as the turns ratio and is represented by the equation: Ip/Is = Np/Ns.

3. What factors affect the magnitude of primary and secondary currents in a transformer?

The magnitude of primary and secondary currents is affected by the turns ratio of the transformer, the load connected to the secondary winding, and the input voltage applied to the primary winding. Additionally, the resistance and impedance of the windings also play a role in determining the current values.

4. Why is it important to properly size the primary and secondary currents in a transformer?

Properly sizing the primary and secondary currents is crucial for the safe and efficient operation of a transformer. If the currents are too high, it can cause overheating and potential damage to the transformer. If the currents are too low, it can result in a loss of power and reduced efficiency.

5. How can the primary and secondary currents be measured in a transformer?

The primary and secondary currents in a transformer can be measured using a current transformer or a clamp meter. A current transformer is a device that is connected to the transformer's secondary winding and measures the current indirectly. A clamp meter is a handheld device that can measure the current flowing through a conductor by clamping around it.

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