Paragraph 4 Energy efficiency requirements for motors

(1)

To determine the minimum efficiency of 50 Hz motors with rated power outputs (P_N) of between 0.12 and 200 kW not provided in Tables 21 to 26, the following formula must be used—

η_{n} = A \times {[\log_{10} (P_{N} / 1 k W)]}^{3} \pm B \times {[\log_{10} (P_{N} / 1 k W)]}^{2} \pm C \times \log_{10} (P_{N} / 1 k W) \pm D

(2)

For the purposes of paragraph (1), A, B, C and D are interpolation coefficients to be determined according to Tables 27 and 28.

(3)

The minimum efficiency of a motor with a rated power output (P) between 0.55 kW and 0.75 kW must be calculated by linear interpolation from the obtained minimum efficiencies of a motor with a rated power output of 0.55 kW and a motor with a rated power output of 0.75 kW.