Can We Replace a 110/220 Turns Transformer with 10/20 Turns?

1:2 Turn Ratio for 110:220? The Turn Ratio is Same, Shall its Rating be Same?

A step up transformer which has 110/220 turns. Can we replace it with 10/20 turns or 1:2? Turns ratio is same, shall its rating be same? Give appropriate reasons?

No. Because we know that flux is directly proportional to the ampere turns (Φ ∝ At). So if we reduce the number of turns i.e. turns ratio, flux will be also reduced which leads to reduce the induced EMF because EMF is directly proportional to the flux (EMF ∝ Φ). If we go about the transformation formula, the calculated value may be right but if we use the EMF equation of the transformer, it shows a different story. Let’s see what happens when we reduce the number of turns in the transformer windings.

• Related Post: Which Transformer is More Efficient When Operates on 50Hz or 60Hz?

Transformer Rating & Parameters

• N₁ = 110 Turns
• N₂ = 220 Turns
• E₁ = 220V
• Flux = Φ_m = 9.01 mW (mille Weber)
• E₂ = ?

When Turn Ratio is 110/220

To find E₂, we know that

E₂/E₁ = N₂/N₁

E₂ = (N₂/N₁) x E₁

Putting the values

E₂ = (220/110) x 220V

 E₂ = 440V 

• Related Post: Can We Operate a 60Hz Transformer on 50Hz Supply Source and Vice Versa?

When Turn Ratio is 10/20

Now, if we use 10/20 Turns ratio instead of 110/220.

E₂ = (N₂/N₁) x V1

E₂ = (20/10) x 220V

 E₂ = 440V 

We can see that the value of step up voltage is same in both case whether we use 10/20 or 110/220 turns.

But I’m lying. It’s not true.

Let’s turn around to the EMF equation of the transformer.

E₁ = 4.44 x f x N₁ Φ_{m ……….. (Primary)}

E₂ = 4.44 x f N₂ Φ_{m ……….(Secondary)}

In case of turn ratio of 110/220

E₁ = 4.44 x 50 x 110 x 9.01 mW 

 E₁ = 220V 

E₂ = 4.44 x 50 x 220 x 9.01 mW 

 E₂ = 440V 

In case of turn ratio of 10/20

E₁ = 4.44 x 50 x 10 x 9.01 mW 

 E₁ = 20V 

E₂ = 4.44 x 50 x 20 x 9.01 mW 

 E₂ = 40V 

• Related Post: Is it Possible to Operate a 50Hz Transformer on 5Hz or 500Hz Frequency?

Hmm. That is a huge different. That’s why we can’t use 10/20 turns ratio instead of 110/220 because flux is directly proportional to the ampere turns (Φ ∝ At). If we reduce the number of turns (turns ratio of the transformer), the amount of produced flux will be reduced because of lower ampere turns which causes to reduce the amount of inducted EMF too i.e. induced EMF is directly proportional to the flux (Φ ∝ EMF).

In short, If we reduce the turn ratio of a transformer from 110/220 to 10/20 or 1:2, The following may occurs.

• The current in the primary winding of the transformer may increase due to reduced amount of impedance (Z) and resistance (R) i.e. low turns means low inductive reactance (X_L) where X_L dependents on the inductance of the turns.
• There may be high power loss due to high current in the primary as well as high power loss (I²R) which may leads to burn the primary windings of the transform.
• The induced EMF will be reduces as well due to low magnetic flux which depends on the number of coil turns.

Related Post: Why Transformer Rated In kVA, Not in KW?

• Related Posts:
• How Find the Rating of Transformer in kVA (Single Phase and Three Phase)?
• Transformer Phasing: The Dot Notation and Dot Convention
• Transformer Efficiency, All day Efficiency & Maximum Efficiency
• TRANSFORMER NAMEPLATE (GENERAL REQUIREMENTS).
• In a Capacitive Circuit, Why the Current Increases When Frequency Increases?
• In an Inductive Circuit, Why the Current Increases When Frequency Decreases?
• Why Power Factor Decreases When Inductance or Inductive Reactance Increases?
• Why Power Factor Decreases When Capacitive Reactance Increases or Capacitance Decreases?