To Select the Right
power Transformer, First Determine the following things:
- Three Phase or Single Phase ,according to load
- Primary voltage, which is the available voltage
- Secondary voltage required by load equipment
- Frequency (in Hz)
- KVA load with possible future increases factored in 0.20
- Is the transformer to be used indoors or outdoors?
- Is the transformer to be floor or wall-mounted?
- Is an auto transformer or a double-wound transformer required?
- Insulation Type (Liquid-Filled or Dry Type)
- Low-Loss Core Material
- Regulation
- Voltage Taps
- Cooling system
- Temperature Class
The manufacturers of transformers recommend that the
connected wattage not exceed 90% of the Transformer's rated wattage. For
example, don't connect more than 450 watts to a 500 watt transformer.
Nominal Data of a power transformer:
|
Description
|
Unit
|
Data
|
|
Rating
Voltages
|
kV
|
11/0.4
|
|
Power
rating
|
KVA
|
1000
|
|
On
Load /Off Load Tapping
|
kV
|
03
Position
|
|
Coupling
|
-
|
Star/Star
|
|
Vector
Group
|
-
|
Yyn0
|
|
Frequency
|
Hz
|
50
|
|
Maximum
Oil Temperature
|
K
|
40
|
|
Hot
Spot Winding Temperature
|
K
|
65
|
|
Temperature
Class
|
|
A
|
|
No
Load Loss
|
kW
|
1
|
|
Full
Load Loss
|
kW
|
3
|
|
No-Load
Current
|
%
|
0.4
|
