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The turns ratio of a transformer is directly proportional to the voltage.

To find the number of turns in the secondary, first calculate the voltage ratio.

24V/115V is a 1:0.2087, if we use this ratio to calculate the turns we get.

345 x 0.2087 = 72 turns.

Another idea to apply (which says the same thing) is that the ratio of the voltages will equal the turns ratio. Here's how that looks:

Voltageprimary / Voltagesecondary = Turnsprimary / Turnssecondary

or just

Vp / Vs = Tp / Ts

Plugging in the numbers will give us

115 volts / 24 volts = 345 turns / Ts , and 115/24 = 345/Ts , and 115 x Ts = 24 x 345 , and Ts = (24 x 345) / 115 , and Ts = 8780 / 115 = 72 turns.

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13y ago
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12y ago

The turns ratio of an ideal transformer is the same as its voltage ratio. In the case of your query, the voltage ratio is:

Us/Up = Ns/Np

So, Ns = Np (Us/Up) = 75 x (2400/120) =1500 turns.

Incidentally, the symbol for 'volt' is an upper-case 'V', not a lower-case 'v'.

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15y ago

This is a 2:1 ratio stepdown transformer. With an output of 120 volts the primary is 240 volts input. See related links for an excellent description of Transformers.

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13y ago

( 345 * (24 / 115) = ) 72 turns on the 24 volt side.

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11y ago

number of turns in secondary is 72

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12y ago

72

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10y ago

72

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13y ago

5:1

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Q: A transformer has primary voltage of 240v and a secondary voltage of 48v what is the turns ratio of this transformer?
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If the voltage in a transformer is twelve volts and the primary coil has ten turns and the secondary coil has twenty what is the voltage across the secondary coil?

I assume the primary has 12 volts applied. The voltage ratio from primary / secondary is equivalent to the turns ratio = 10/20, so the primary voltage is 1/2 of the secondary voltage. The secondary voltage is 24.


Does a transformer increase amps?

The primary current is determined by the secondary current, not the other way around. For example, a step up transformer will step up the primary voltage in proportion to the turns ratio of the transformer. Any secondary current is then determined by the secondary voltage and the load, NOT by the primary current. The primary current is then determined by the secondary current in proportion to the reciprocal of the turns ratio.


What value for a transformer determines the amount of voltage that is stepped up or down?

For an ideal transformer, the voltage ratio is exactly the same as its turns ratio. So if, for example, there are twice as many turns on the secondary winding as there are on the primary winding, then the secondary voltage will be twice that of the primary and the transformer will be a 'step up' type.


How do you find the secondary to primary transformer voltage ratio?

Turns Ratio = (Primary turns / Secondary turns) To calculate the turns ratio you have to actually know the number of turns or wraps on the primary and secondary coils. Nobody knows that usually the manufacture of the transformer doesn't even know. So what you can use as and equivalent is to calculate the voltage ratio. So what you typically need to look for is the Input voltage and divid it by the output volatge. Usually that would be as follows; (Primary Voltage/Secondary Voltage) = Voltage Ratio


Difference between input and output transformer?

The 'input' side of a transformer is called its 'primary' side, whereas the 'output' side is termed its 'secondary' side. The ratio of its secondary to primary voltage is equal to the ratio of the number of turns in the secondary windings to the number of turns in the primary winding. So if, for example, a transformer's secondary winding has twice as many turns as its primary winding, then the secondary winding will produce twice the voltage applied to the primary winding.

Related questions

How do you calculate transformer voltage ratio test?

Secondary voltage / primary voltage


If a transformer has 20 primary windings and 100 secondary windings and the secondary voltage is 25 what is the primary voltage?

Transformer step-up/step-down voltage is turns-ratio, so if a transformer has 20 primary windings and 100 secondary windings (a turns-ratio of 1 to 5) and the secondary voltage is 25, then is the primary voltage is 5.


What is the secondary voltage of a transformer with the turn ratio of 5 to1 and primary volts of 200?

The secondary voltage of a transformer with a turns ratio of 5 to 1, and primary voltage of 200 is 40. (5 to 1)


How many turns in secondary coil in Transformer?

It depends on the type of transformer.If it is a step up transformer the number of turns in secondary side is higher than primary.Stepdown means it will have fewer number of windings on the secondary side turns when compared with the primary side.An isolation transformer has the same number of windings on the primary as the secondary.The ratio of the windings is proportional to the increase or decrease in the secondary voltage. For example, twice the windings doubles the voltage and 1/2 the windings halves the secondary voltage. The isolation transformer is denoted as 1:1 and has the same voltage on the secondary as the primary.The ratio of secondary turns to primary turns is the same as the ratio of secondary voltage to primary voltage.e.g. if the secondary to primary turns ratio is 1/10, then the secondary voltage will be one tenth of the primary voltage.


How can find the primary turns of the transformer knowing the primary voltage of the transformer?

The ratio of the primary voltage to the secondary voltage is proportional to the ratio of windings. So if the primary voltage is 120 volts and the secondary is 240 volts there are twice as many turns in the secondary.AnswerAs the previous answer says, you can work out the turns ratio of a transformer, but knowing the primary and secondary voltages will not help you determine how many turns are on each winding.


What are the output voltage and current of a transformer determined by?

The secondary (output) voltage is determined by the primary voltage and the turns ratio of the transformer. The secondary current is determined by the secondary voltage and the load resistance.


What is the definition of transformation ratio?

The turns ratio of a transformer is the number of primary turns to secondary turns. This defines how the transformer will change the voltage and current. For N1 primary turns, and N2 secondary turns, N1/N2 will be the turns ratio; the secondary voltage will be:the primary voltage x (N2/N1); The secondary current will be:primary current x (N1/N2)


If the voltage in a transformer is twelve volts and the primary coil has ten turns and the secondary coil has twenty what is the voltage across the secondary coil?

I assume the primary has 12 volts applied. The voltage ratio from primary / secondary is equivalent to the turns ratio = 10/20, so the primary voltage is 1/2 of the secondary voltage. The secondary voltage is 24.


Does a transformer increase amps?

The primary current is determined by the secondary current, not the other way around. For example, a step up transformer will step up the primary voltage in proportion to the turns ratio of the transformer. Any secondary current is then determined by the secondary voltage and the load, NOT by the primary current. The primary current is then determined by the secondary current in proportion to the reciprocal of the turns ratio.


How do you calculate primary current?

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.


Why should the secondary of a voltage transformer not be short circuited?

A voltage transformer takes a primary voltage and steps it down to a smaller secondary voltage. This type of transformer will attempt to keep the secondary voltage at a specific ratio of the primary voltage. If you short it, massive current flow in the secondary is required to do this. For a similar reason a CT should never be open circuited - because it attempts to push a specific ratio of primary current through the secondary. If you open circuit the secondary, it takes a massive voltage on the secondary to accomplish this.


What value for a transformer determines the amount of voltage that is stepped up or down?

For an ideal transformer, the voltage ratio is exactly the same as its turns ratio. So if, for example, there are twice as many turns on the secondary winding as there are on the primary winding, then the secondary voltage will be twice that of the primary and the transformer will be a 'step up' type.