Comparison (similarity/difference) between Two Winding Transformer and Autotransformer
		| 
Sr. No. | 
Point of comparison | 
Two winding Transformer | 
Auto Transformer | 
| 
1 | 
Two types | 
Step down and step up | 
Similar types | 
| 
2 | 
Cost | 
More  | 
Less | 
| 
3 | 
Construction | 
Core and two winding  | 
Core and only one winding  | 
| 
4 | 
Weight of copper  | 
Wc | 
(1 – k) Wc  which is < wc | 
| 
5 | 
Voltage | 
Fixed values | 
Variable on secondary  | 
| 
6 | 
Electrical Isolation  | 
Two windings are electrically isolated  | 
Two winding are integral (Not isolated). | 
| 
7 | 
Size | 
Large  | 
Compact  | 
| 
8 | 
Efficiency  | 
Lesser | 
More | 
| 
9 | 
Voltage regulation  | 
More (poor) | 
Lesser (Better) | 
| 
10 | 
Applications | 
     1.Power transformer 
     2.Distribution transformer 
     3.Isolation transformer 
     4. Instrument transformer 
     5. Welding transformer | 
     1. Starting of motor used as autotransformer starter 
     2. Varias for charging voltage in drama stages in drama stage 
     3. Dimmerstat | 
 
					