Yaskawa FSP Amplifier - Manual (Page 141)

FSP Amplifier User’s Manual Chapter 5: Parameter Settings and Functions
5-74
5.6.2. Calculating the Regenerative Power Capacity
„ Simple Calculation Method
When driving a servomotor normally along the horizontal axis, check the
external regenerative resistor requirements using the calculation method
shown below.
Servo Amplifiers with Capacities of 400 W or Less
Servo amplifiers with capacities of 400 W or less do not have built-in
regenerative resistors. The energy that can be absorbed by capacitors is
shown in the following table. If the rotational energy in the servo system
exceeds these values, then connect a regenerative resistor externally.
Voltage
Applicable Servo
Amplifiers
Regenerative Energy
that Can Be Processed
(Joules)
Comments
FSP-A3B* 7.8
100 V
FSP-A5B* to FSP-02B* 15.7
Value when the input voltage
is 100 VAC
FSP-A3A*, FSP-A5A* 18.5
200 V
FSP-01A* to -04A* 37.1
Value when the input voltage
is 200 VAC
Calculate the rotational energy in the servo system using the following
equation:
E
S
=
( )
12566
N x J
2
M
Joules
Where: J = J
M
+ J
L
J
M
: Servomotor rotor inertia (kg·m 2 ) (oz·in·s 2 )
J
L
: Motor axis conversion load inertia (kg·m 2 ) (oz·in·s 2 )
N
M
: Rotation speed of the servomotor (rpm)
Servo Amplifiers Capacities of 0.5 kW to 5.0 kW
Servo amplifiers with capacities of 500 W to 5 kW have built-in
regenerative resistors. The allowable frequencies for just the servomotor
during acceleration/deceleration operation, in the run cycle from 0 Æ
maximum rotation speed Æ 0, are summarized in the following table.
Convert the data into the values obtained with actual rotation speed used
and load inertia to determine whether an external regenerative resistor is
needed.