5.2 Specifications and Ratings: Small Capacity
5.2.5 Allowable Load Moment of Inertia
5-8
5.2.5
Allowable Load Moment of Inertia
The allowable load moments of inertia (motor moment of inertia ratios) for the Servomotors are
given in the
. The values are determined by the regenerative energy processing
capacity of the SERVOPACK and are also affected by the drive conditions of the Servomotor.
Perform the required Steps for each of the following cases.
Exceeding the Allowable Load Moment of Inertia
Use one of the following measures to adjust the load moment of inertia to within the allowable
value.
•
Reduce the torque limit.
•
Reduce the deceleration rate.
•
Reduce the maximum motor speed.
If the above steps is not possible, install an external regenerative resistor.
SERVOPACKs without Built-in Regenerative Resistors
The following graph shows the allowable load moment of inertia scaling factor of the motor
speed (reference values for deceleration operation at or above the rated torque). Application is
possible without an external regenerative resistor within the allowable value. However, an Exter-
nal Regenerative Resistor is required in the shaded areas of the graphs.
Note: Applicable SERVOPACK models: SGD7S-2R8A and -2R8F
When an External Regenerative Resistor Is Required
Install the External Regenerative Resistor.
Refer to the following catalog for information on External Regenerative Resistors.
AC Servo Drives
Σ
-7 Series (Manual No.: KAEP S800001 23)
An Overvoltage Alarm (A.400) is likely to occur during deceleration if the load moment of iner-
tia exceeds the allowable load moment of inertia. SERVOPACKs with a built-in regenerative
resistor may generate a Regenerative Overload Alarm (A.320).
Install an External Regenerative Resistor when the built-in regenerative resistor cannot pro-
cess all of the regenerative power.
Refer to the following catalog for the regenerative power (W) that can be processed by the
SERVOPACKs.
AC Servo Drives
Σ
-7 Series (Manual No.: KAEP S800001 23)
Information
0
5
10
15
20
25
30
0
100
200
300
400
500
600
700
0
100
200
300
400
500
600
700
0
100
200
300
400
500
600
700
SGM7F-04B
0
2
4
6
8
10
12
14
16
SGM7F-08C
0
5
10
15
20
25
30
35
40
45
SGM7F-10B
Motor speed (min
-1
)
Allowable load moment of inertia
scaling factor (times)
Allowable load moment of inertia
scaling factor (times)
Allowable load moment of inertia
scaling factor (times)
Allowable load moment of inertia
scaling factor (times)
Motor speed (min
-1
)
Allowable load moment of inertia
scaling factor (times)
Motor speed (min
-1
)
Allowable load moment of inertia
scaling factor (times)
0
5
10
15
20
25
30
0
100
200
300
400
500
600
700
0
100
200
300
400
500
600
700
SGM7F-02A
0
5
10
15
20
25
30
35
40
SGM7F-05A
0
100
200
300
400
500
600
700
0
5
10
15
20
25
30
35
40
SGM7F-07A
Motor speed (min
-1
)
Motor speed (min
-1
)
Motor speed (min
-1
)
