Page 76 - E24 Electrical Notebook

72 - Green T.HE High Efficiency Transformers

Eco Design

Green T.HE high efficiency transformers meet the latest European Commission's Ecodesign Directive, which outlines the parameters transformers must
adhere to in order to meet efficiency requirements, defined by the maximum load and no-load losses a transformer can record.

Classification

The classification of a cast resin transformer depends on the value of the no-load losses (Po), as well as the load losses (Pk), characteristics of the machine.
More precisely, Po losses are independent from the load and remain constant for the whole period the transformer is connected to the electric power
network. On the other hand, Pk losses only occur when the transformer is connected to a load and are proportional to the square of the load itself.

Certifications & Acceptance Tests

Prior to Legrand cast resin transformers being supplied to the customer, they are individually inspected and must pass the
acceptance and, when necessary, type tests, if they are required at the time of order.

At the end of the acceptance tests a specific inspection certificate is delivered with each transformer.

Acceptance tests IEC 60076-1
Measurement of winding resistance IEC 60076-1
Measurement of transformation ratio and check of polarity and connections IEC 60076-1
Measurement of short-circuit voltage and losses due to load IEC 60076-1
Measurement of no-load losses and no-load current IEC 60076-3
Insulation test with applied voltage IEC 60076-3
Insulation test with induced voltage IEC 60076-11
Measurement of partial discharges

Type test (on request) IEC 60076-3
Atmospheric impulse test IEC 60076-2
Temperature rise test

Special tests (on request) IEC 60076-10
Measurement of sound level IEC 60076-11
Short-circuit withstand test

Legrand Electric Ltd Tel : +44 (0) 345 605 4333
Great King Street North Fax : +44 (0) 345 600 6366
Birmingham
B19 2LF Website : www.legrand.co.uk
United Kingdom Email : powersales.uk@legrand.co.uk