Copper Savings in an Auto Transformer
Now, we’ll talk about the how much copper is saved in an auto transformer when compared to a standard two-winding transformer.
Any winding’s copper weight is known to be depends by its length and cross-sectional area. Again, the length of a conductor in a winding is inversely proportional to the number of turns it has, and the cross-sectional area varies depending on the rated current.
So weight of copper in winding is directly proportional to result of number of turns and rated current of the winding.
Hence, the weight of copper in section AC is directly proportional to,
(N1 – N2) I
also, similarly, weight of copper in the section BC proportional to,
N2( I2– I1)
Consequently, total weight of copper in the winding of auto transformer proportional to,
(N1 – N2) I1 = N2 ( I2 – I1)
N1 I1 – N2 I1 + N2 I2 – N2 I1
N1 I1 + N2 I2 – 2 N2 I1
2N1 I1 – 2N2 I1
2(N1 I1 – N2 I1)
Similarly, it can be demonstrated that the weight of copper in a two-winding transformer is directly proportional to,
N1 I1 + N2 I2
2N1 I1
N1 I1 + N2 I2
2N1 I1 (Since, in a transformer N1 I1 = N2 I2)
Assume that, Wa and Wtw are weight of copper in auto transformer and two winding transformer separately,
Hence, Wa / Wtw = 2 ( N1 I1 – N2 I1 ) / 2( N1 I1 )
= N1 I1 – N2 I1 / N1I1 = ( 1 – N2 I1 / N1 I1 )
= ( 1 – N2/ N1 )
= 1-K
Wa = Wtw ( 1 – k)
Wa = Wtw – kWtw
Saving of copper in auto transformer compared with two winding transformer,
W tw – Wa = kw tw
Auto transformer employ’s just single winding per phases work as against two particularly separate windings in a conventional transformer.
Auto Transformer
An Auto Transformer refers to a transformer that features a single winding wound around a laminated core. An autotransformer is like a two-winding transformer however contrast in the manner the primary winding and secondary winding are interrelated. A piece of the winding is common to both the primary side and secondary sides.
In this article, we will be going through Auto Transformer, First we will start our Article with What is an AutoTransformer, next, we will go through the construction and Working of an Autotransformer, Then we will go through the Autotransformer Theory and Copper Savings in an Auto Transformer, At last, we will conclude our Article with Advantages, Disadvantages, Applications and Some FAQs.
Table of Content
- AutoTransformer
- Construction and Working
- Copper Savings
- Advantages
- Disadvantages
- Applications