Transformer Nameplate Data – Explain the Rating and Features

Electrical Technology

General Requirements of a Transformer Nameplate to Show the Characteristics

Following are the minimum information and data printed on a transformer nameplate from the designer and manufactures. The standards require the following information and data for transformers rated above 500 kVA (and 1000kVA = 1MVA.

Name of manufacturer
Serial number
year of manufacture
Number of phases
kVA or MVA rating
Frequency
Voltage ratings.
Tap voltages.
Connection diagram.
Cooling class
Rated temperature in °C
Polarity (for Single Phase Transformers)
Phasor or vector diagram (For Polyphase or Three Phase Transformers)
% impedance.
Approximate mass or weight of the transformer
Type of insulating liquid.
Conductor material of each winding.
Oil volume (of each transformer Container/Compartment)
Instruction for Installation and Operation

Nameplate Rating Of a Transformer

The data on the Nameplate of a transformer contains of kVA rating, Voltage Rating, Frequency, Number of Phases, Temperature, Type of Cooling, % Impedance and Reactance, Name of Manufacture, Year of Manufacture etc.

A Typical Nameplate of a Transformer as follows.

S.No.	Description of Data to be given	Ra-marks for example
1	Manufacturer’s Name:	ABB/206788
2	Manufacture’s Serial Number	224106
3	Kind of Transformer	Power Transformer
4	Relevant Standard Year	I.S/P.S/B.S/ IEC /DIS/JIS NEMA
5	Year of Manufacture	20….
6	Number of Phase 3	3
7	Rated Power	1000kVA = 1MVA
8	Rated Frequency:	50Hz
9	Rated Voltages:	HV 33 kV, LV 11 kV,
10	Rated Currents	HV______,LV_______.
11	Vector Group Symbol	__________________
12	% Impedance Voltage .. ( At Rated Current)	__________________
13	% Reactance Voltage in % :	__________________
14	Types of Cooling	ONAN
15	Total Weight .. Mass or insulating Oil .. Transportation Weight .. Untanking Weight	__________Kg __________Kg __________Kg __________Kg
16	Insulating liquid ( if Not Oil) Types:	__________
17	Quantity of Oil ( Liters):	__________
18	Details about Tap-Changer	__________
19	Rated insulation Level: .. Power-Frequency withstand Voltage	__________ kV(rms)
20	Other	…………………….

Also shown in below image.

Below is a 100kVA (Three-Phase) Transformer nameplate.

Click image to enlarge.