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If it's a step up or step down transformer and you know the secondary side current, multiply the secondary current by the turns ratio. If you know the power in the secondary winding but not the current, divide the secondary power by the secondary voltage to get the secondary current and then multiply the secondary current by the turns ratio to get the primary current. The turns ratio is the number of turns on the secondary winding divided by the number of turns on the primary winding. For a step up transformer, the turns ratio will be greater then one. If it's a step down transformer, then the turns ratio will be less than one. If you don't know the turns ratio, divide the secondary voltage by the primary voltage to get the turns ratio.

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16y ago
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8y ago

The primary current is calculated as the secondary current divided by the voltage ratio. So if the voltage ratio is 2:1, the current ratio is 1:2.

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Q: How do you calculate primary current?
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How calculate primary current in transformer the 50kva rating and 11kvprimary voltage?

The primary current is determined by the secondary current. So, if you don't know the secondary current, you cannot work out the primary current.If the secondary isn't connected to the load, then the primary current is simply the primary voltage divided by the impedance of the primary winding.You can, though, work out the 'rated' primary current (i.e. the value of current the primary can carry, continuously). For a single-phase transformer, this will be its rated apparent power (in volt amperes) divided by its rated primary voltage. So, in this particular case, we are looking at:rated primary current = (50 x 103) / (11 x 103) = 4.55 A


How do you calculate turns ratio for current transformer?

The turns ratio is the number of primary turns divided by the number of secondary turns. This is the same ratio as input current to output current. ie the turns ratio N = I1/I2


What is full load-current in primary?

This is the current flowing in the primary circuit when full-load current flows in the secondary circuit.


What is Primary Current?

Primary current is a flow to be measured that cannot be safely passed through the measuring device. A current transformer is used to provide a lower level, secondary current that can be passed safely through the measuring device. Primary current is measured as a secondary current, multiplied by the turns ratio in the current transformer.


What is the current in 1KVA Transformer?

Tis question is incompleet.1000 va =1 kva.This is the power capacity of transformer. A transformer having 2 currents Primary current and secondary current . for that we required both voltage. Simply we can calculate by a formula Voltage x Current x 0.8(power factor)=1000.

Related questions

How do you calculate current on the primary side of a transformer only knowing the turns ratio and the voltage ratio?

The primary current on a loaded transformer depends on the secondary current, which is determined by the load. So, if you know the secondary load current, then you can use the turns ratio of the transformer to determine the primary current:Ip/Is = Ns/Np


How should I calculate this. A single phase transformer is rated at 99kVA The primary voltage is 6.6kV and the secondary voltage is 220V Assume no losses and calculate The full load primary current?

First find the ratio of the transformer. 6600/220 volts. Second find the secondary current, I = W/E, 99000/220. Third divide the secondary current by the transformer ratio. The answer will be the primary current. To check your answer (W (or VA) = V x A) multiply the primary current times the primary voltage and the secondary current times the secondary voltage and they should both equal the transformer's kVA.


How calculate primary current in transformer the 50kva rating and 11kvprimary voltage?

The primary current is determined by the secondary current. So, if you don't know the secondary current, you cannot work out the primary current.If the secondary isn't connected to the load, then the primary current is simply the primary voltage divided by the impedance of the primary winding.You can, though, work out the 'rated' primary current (i.e. the value of current the primary can carry, continuously). For a single-phase transformer, this will be its rated apparent power (in volt amperes) divided by its rated primary voltage. So, in this particular case, we are looking at:rated primary current = (50 x 103) / (11 x 103) = 4.55 A


How do you calculate primary AC for 3 phase ac input if output load dc current is known?

DC Current divided by 1.225


How do you calculate primary curuent?

Current is calculated on the load. If your question on transformer primary current, then use the formula N1I1=N2I2, where N1 and N2 are primary and secondary coil turns and I1 and I2 are current in respective coils. This is very basic simple formula. You have reframe your question more specifically.


What is rated voltage and current in transformers and how to calculate them if given 50k VA?

Rated voltage is the voltage at primary side. Rated current can be found from the equation, Rated Current= Output KVA / Output rated voltage


What is line side amps for 1000kva transformer?

It depends on the voltage on line side. KVA is simply thousand volt-amps, so you need to know voltage in order to calculate amperes.Another AnswerThe rated primary current is the rated apparent power of the transformer, divided by the rated primary current. However, the actual primary current is determined by the actualsecondary load current in proportion to the reciprocal of the turns ratio.


How does the product of voltage and current in the primary compare with the product of voltage and current in the secondary?

The current in the secondary when the voltage is twice the primary will be one half of the primary. The current in the primary when the voltage is twice the secondary will be twice the secondary.


How do you calculate turns ratio for current transformer?

The turns ratio is the number of primary turns divided by the number of secondary turns. This is the same ratio as input current to output current. ie the turns ratio N = I1/I2


How do you calculate current flow transformer when 240 Vrms is supply?

The secondary current of a transformer is determined by the load and the secondary voltage applied to that load, and this, in turn, will determine the primary current by the inverse of the turns ratio. However, if you are asking about a transformer's rated secondary and primary currents, then you need to divide the transformer's apparent power rating (expressed in volt amperes) by the rated secondary and primary voltages respectively.


What is full load-current in primary?

This is the current flowing in the primary circuit when full-load current flows in the secondary circuit.


When secondary coil is open there is no current in the primary coil WHY?

I am assuming the question is about the power / distribution transformer and not the current transformer. The primary current is a function of load connected on secondary. With the open secondary, there is no load, no current, it is open circuit. Hence no primary current. However there is always some small amount of no load current in the primary winding.