Resistor braking192Calculating the maximum braking power (Pbr )• Braking energy transferred during any ten minute period must be less than orequal to the energy transferred during the reference braking cycle.• The braking power must not exceed the rated maximum value Pbrmax .Example 1Duration of a braking cycle is 30 minutes. The braking time is15 minutes.Result: If the braking time exceeds 10 minutes, the braking is consideredcontinuous. The allowed continuous braking power is 10% of the Maximum BrakingPower (Pbrmax ).Example 2Duration of a braking cycle is three minutes. The braking time is40 seconds.Result: The maximum allowed braking power for the cycle is 37% of the rated valuegiven for the reference cycle.n x Pbr x tbr < Pbrmax x 60 sn = Number of braking pulses duringa ten minute periodPbr = Maximum allowed braking power (kW).tbr = Braking time (s)Pbrmax = Maximum Braking Powerfor a reference cycle (kW)Pbr < Pbrmax1.2.PbrmaxtPbr600 sPbr < Pbrmax x 60 s4 x 40 s = 0.375 x PbrmaxtbrT = Duration of braking cycle1.2. Pbr < Pbrmax O.K.
