Chapter 2 Installation  ASDA-A2 
Revision February, 2017   2-13 
Servo Drive 
(kW) 
Motor 
Rotor Inertia 
J (× 10-
4kg.m2) 
Regenerative power 
from empty load 
3000r/min to stop 
Eo (joule) 
The maximum 
regenerative power of 
capacitance 
Ec (joule) 
Medium 
–High 
Inertia 
0.75 
ECMA-L△1305 
13.1 16.20  42.43 
1.5 
ECMA-L△1313 
23.6 29.18  42.43 
3.0 
ECMA-L△1830 
54.95 67.93  42.43 
3.0 
ECMA-J△1330 
12.7 15.70  42.43 
4.5 
ECMA-L△1845 
77.75 96.12  51.17 
5.5 
ECMA-L△1855 
99.78 123.35  57.41 
7.5 
ECMA-L△1875 
142.7 176.41  62.40 
High 
Inertia 
1.0 
ECMA-L△1308 
17.1 84.56  42.43 
1.5 
ECMA-M△1309 
11.18 55.29  57.41 
Eo= J * wr
2
/182 (joule), Wr: r/min 
 
Assume that the load inertia is N times to the motor inertia and the motor decelerates from 
3000r/min to 0, its regenerative energy is (N+1) x Eo. The consumed regenerative resistor is (N+1) 
×  Eo - Ec joule. If the cycle of back and forth operation is T sec, then the power of regenerative 
resistor it needs is 2× ((N+1) x  Eo - Ec) / T. 
Followings are the calculation procedure: 
Steps  Item  Calculation and Setting Method 
1 
Set the capacity of regenerative 
resistor to the maximum 
Set P1-53 to the maximum value 
2 
Set T cycle of back and forth 
operation 
Enter by the user 
3  Set the rotational speed wr  Enter by the user or read via P0-02 
4  Set the load/motor inertia ratio N  Enter by the user or read via P0-02 
5 
Calculate the maximum regenerative 
energy Eo 
Eo= J * wr
2
/182 
6 
Set the absorbable regenerative 
energy Ec 
Refer to the above table 
7 
Calculate the needful capacitance of 
regenerative resistor 
2 x ((N+1) x Eo – Ec) / T