Chapter 2 Installation and Storage
ASDA-B2
2-10
Revision September 2013
Servo Drive
(kW)
Servo Motor
Rotor Inertia
J (× 10
-4
kg.m
2
)
Regenerative power
from empty load
3000r/min to stop
Eo (joule)
Max. regenerative
power of
capacitance
Ec(joule)
3.0
ECMA-E21830
54.95
271.73
28
ECMA-F21830
54.95
271.73
28
High
Inertia
0.4 ECMA-G21303
8.17
40.40
8
0.75 ECMA-G21306
8.41
41.59
14
1.0 ECMA-G21309
11.18
55.29
18
Eo = J x wr
2
/182 (joule), Wr : r/min
If the load inertia is N × motor inertia, the regenerative power will be (N+1) x E0 when
servo motor brakes from 3000r/min to 0. Then, the regenerative resistor can dissipate:
(N+1) x E0 - Ec (joule). If the time of repeat operation cycle is T sec, then the
regenerative power = 2 x ((N+1) x E0 - Ec) / T.
The calculating procedure is as follows:
Step
Procedure
Equation and Setting Method
1
Set the capacity of regenerative
resistor to the maximum
Change the value of P1-53 to maximum
2
Set the operation cycle T
Input by the users
3
Set motor speed wr
Input by the users or read via P0-02 Drive State
Display
4
Set load/motor inertia ratio N
Input by the users or read via P0-02 Drive State
Display
5
Calculate the max. regenerative
power Eo
Eo = J x wr
2
/182
6
Set the regenerative power Ec
that can be absorbed
Refer to the table above
7
Calculate the required
regenerative power capacity
2 x (N+1) x Eo
-
Ec
)
/ T
For example:
If we use 400W servo drive, the time of repeat operation cycle is T = 0.4 sec, max.
motor speed is 3000r/min, the load inertia = 7 × motor inertia, then the necessary the
power of regenerative resistor = 2 x ( (7+1) × 1.68 - 8) / 0.4 = 27.2W. If the calculation
result is smaller than regenerative power, we recommend the users to use the built-in
60W regenerative resistor. Usually the built-in regenerative resistor provided by ASDA-
B2 series can meet the requirement of general application when the external load
inertia is not excessive.
The users can see when the capacity of regenerative resistor is too small, the
accumulated power will be larger and the temperature will also increase. The fault,
ALE05 may occur if the temperature is over high. The following figure shows the actual
operation of regenerative resistor.
VARITEL INGENIERIA ELECTRONICA S.A.
[email protected] - www.varitel.com - Tel. (54) 11-4243-1171 / Fax: (54) 11-4292-7545
Manuel Baliña 456, Lomas de Zamora (B1832CCJ) Buenos Aires, Argentina.