YASKAWA SGDS Sigma III Series, User Manual

Page: 324 / 376

11.1 Servomotor Capacity Selection Examples
11-7
Calculate the rotational energy E
s
in the servomotor from the following equation:
E
S
= J × (N
M
)
2
/182 (joules)
• J = J
M
+ J
L
• J
M
:
Servomotor rotor moment of inertia (kg·m
2
)
• J
L
:
Load converted to shaft moment of inertia (kg·m
2
)
• N
M
:
Rotation speed used by servomotor (RPM)
(b) SERVOPACKs with Capacities of 0.5 to 1.0 kW
Servomotors with capacities of 0.5 to 1.0 kW have built-in regenerative resistors. The allowable frequencies
for just the servomotor in acceleration and deceleration operation, during the rotation speed cycle from 0 to
the maximum rotation speed to 0, are summarized in the following table.
Convert the data into the values obtained with actual rotation speed and load moment of inertia to determine
whether an external regenerative resistor is needed.
Operating Conditions for Allowable Regenerative Frequency Calculation
Use the following equation to calculate the allowable frequency for regeneration mode operation.
Voltage
Applicable
SERVOPACKs
Regenerative
Energy that Can
be Processed
(joules)
Remarks
100 V
SGDS-A5F to -02F
28.6
Value when main circuit input voltage is 100 VAC
SGDS-04F
39.0
200 V
SGDS-A5A
15.2
Value when main circuit input voltage is 200 VAC
SGDS-01A to -04A
30.5
Voltage
Series
Allowable Frequencies in
Regenerative Mode (times/min)
Capacity
Symbol
05 06 08 10
200 V SGMAH
−
110 46
−
SGMPH
− − 16 −
SGMSH
− − −
19
Speed reference
Servomotor rotation speed
Servomotor-generated torque
Load moment of inertia = 0 (motoronly)
Regeneration mode
T
(Operating cycle)
Allowable frequency = 1/T (times/min)
Maximum rotation speed
Maximum torque
0
Maximum torque
0
0
t
t
t
Allowable frequency =
Allowable frequency for Servomotor only
(1 + n)
×
Max. rotation speed
Rotation speed
2
(times/min)