Sigma-II Series SGM*H/SGDH USER'S MANUAL - Esco Drives ...

11 Appendix11.1.3 Calculating the Required Capacity of Regenerative Resistors(a) Calculation ProcedureThe procedure for calculating the regenerative capacity is as follows:Step Item Symbol Equation1 Calculate the rotational energy of the servomotor.E S ES = JN 2 M /1822 Calculate the energy consumed by load loss E L E L = (π/60) N M T L t Dduring the deceleration period.3 Calculate the energy lost from servomotorwinding resistance.E M (Value calculated from “(b) ServomotorWinding Resistance Loss”diagrams) × t D4 Calculate the SERVOPACK energy that canbe absorbed.5 Calculate the energy consumed by the regenerativeresistor.6 Calculate the required regenerative resistorcapacity (W).E C Calculate from “(3) SERVO-PACK’s Absorbable Energy” diagrams.E K E K = E S − (E L +E M +E C )W K W K = E K / (0.2 × T)Note: 1. The “0.2” in the equation for calculating W K is the value for when the regenerative resistor’sutilized load ratio is 20%.2. The units for the various symbols are as follows:E S to E K : Energy joules (J)T L : Load torque (N·m)W K : Regenerative resistor required capacity (W)t D : Deceleration stopping time (s)J: (= J M + J L )(kg·m 2 )T: Servomotor repeat operation period (s)N M : Servomotor rotation speed (min -1 )If the above calculation determines that the amount of regenerative power (Wk) processed by the built-inresistor is not exceeded, then an external regenerative resistor is not required.If the amount of regenerative power that can be processed by the built-in resistor is exceeded, then install anexternal regenerative resistor for the capacity obtained from the above calculation.If the energy consumed by load loss (in step 2 above) is unknown, then perform the calculation using E L = 0.When the operation period in regeneration mode is continuous, add the following items to the above calculationprocedure in order to find the required capacity (W) for the regenerative resistor.• Energy for continuous regeneration mode operation period: E G (joules)• Energy consumed by regenerative resistor: E K = E S - (E L + E M + E C ) + E G• Required capacity of regenerative resistor: W K = E K / (0.2 × T)Here, E G = (2π/60) N MG T G t G• t G : Same operation period (s) as above• T G : Servomotor’s generated torque (N·m) in continuous regeneration mode operation period• N MG : Servomotor rotation speed (min -1 ) for same operation period as above11-10