Delta ASD-B2-0121-B User Manual page 32

Servo Drive
(kW)
0.4 ECMA-G21303
High
0.75 ECMA-G21306
Inertia
1.0 ECMA-G21309
Eo = J x wr /182 (joule)
2
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
Set the capacity of
1 regenerative resistor to the
maximum
2 Set the operation cycle T
3 Set motor speed wr
4 Set load/motor inertia ratio N
Calculate the max.
5
regenerative power Eo
Set the regenerative power Ec
6
that can be absorbed
Calculate the required
7
regenerative power capacity
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.
Revision June 2010
Rotor Inertia
Servo Motor
J (× 10
, Wr : r/min
Procedure
Regenerative power
from empty load
3000r/min to stop
kg.m 2 )
-4
Eo (joule)
8.17 40.40
8.41 41.59
11.18 55.29
Equation and Setting Method
Change the value of P1-53 to maximum
Input by the users
Input by the users or read via P0-02 Drive State
Display
Input by the users or read via P0-02 Drive State
Display
Eo = J x wr /182
2
Refer to the table above
2 x (N+1) x Eo－Ec）/ T
Chapter 2 Installation and Storage
Max. regenerative
power of
capacitance
Ec(joule)
8
14
18
2-11