3.3 Determining the Resistance of the Dynamic Brake Resistor
3.3.1 How to Determine the Resistance of the Dynamic Brake Resistor
3-4
3.3
Determining the Resistance of the Dynamic Brake Resistor
3.3.1
How to Determine the Resistance of the Dynamic Brake
Resistor
Refer to the Servomotor’s characteristic graph to determine the dynamic brake resistance that
will satisfy the restrictions to the instantaneous maximum brake torque of the equipment or
machine.
Refer to the following section for Servomotor characteristic graphs.
3.3.2 Brake Torque and Dynamic Brake Resistance Characteristics
If the brake torque does not require reduction, set the resistance of the connected dynamic
brake resistor as shown in the following table.
WARNING
Do not set the resistance of the dynamic brake resistor to a value less than the minimum
allowed resistance.
There is a risk of burning in the SERVOPACK or Servomotor, damage to the machine, or injury.
•
Increasing the dynamic brake resistance will also increase the coasting distance proportionally.
•
The SGD7S-R70A to -2R8A, SGD7S-R70F to -2R8F, and SGD7W-1R6A to -2R8A do not sup-
port a dynamic brake. For these SERVOPACKs, the brake torque is limited to the friction of the
Servomotor and the equipment or machine.
Model
Minimum Allowed
Dynamic Brake Resistance (±5%)
SGD7S-
R70A to 2R8A,
R70F to 2R8F
–
3R8A to 7R6A
6
Ω
120 A (three-phase input)
3.5
Ω
180A to 200A
3
Ω
330A
1.5
Ω
470A to 550A
1
Ω
590A to 780A
0.6
Ω
SGD7W-
1R6A to 2R8A
–
5R5A to 7R6A
6
Ω
Under the following conditions, the dynamic brake resistance would be 9
Ω
.
•
Linear Servomotor Model: SGLTW-80A600B
•
Brake force limit: 2000 N
Important
Example
In
s
tantaneou
s
maximum
dynamic brake force [N]
Dynamic brake re
s
i
s
tance [
Ω
]
5
10
15
20
25
3
0
3
5
40
0
3
000
0
500
1000
1500
2000
2500
S
GLTW-80A600B
9
Ω
