Dynamic Brake Characteristics - Mitsubishi Electric GENERAL PURPOSE AC SERVO MR-E- A/AG Instruction Manual

12. CHARACTERISTICS

12.3 Dynamic brake characteristics

Fig. 12.3 shows the pattern in which the servo motor comes to a stop when the dynamic brake is operated.
Use Equation 12.2 to calculate an approximate coasting distance to a stop. The dynamic brake time
constant varies with the servo motor and machine operation speeds. (Refer to Fig. 12.4)
Emergency stop(EMG)
J
V
0
L
t
1
e
max
60
J
L : Maximum coasting distance .................................................................................................[mm][in]
max
Vo : Machine rapid feedrate ......................................................................................... [mm/min][in/min]
J : Servo motor inertial moment................................................................................. [kg cm
M
J : Load inertia moment converted into equivalent value on servo motor shaft..... [kg cm
L
: Brake time constant ........................................................................................................................ [s]
t : Delay time of control section........................................................................................................... [s]
e
(There is internal relay delay time of about 30ms.)
16
14
12
10
8
6
4
2
0
0 500 1000 1500 2000 2500 3000
a. HC-KFE series
Use the dynamic brake at the load inertia moment indicated in the following table. If the load inertia
moment is higher than this value, the built-in dynamic brake may burn. If there is a possibility that the
load inertia moment may exceed the value, contact Mitsubishi.
ON
OFF
V
Machine speed
Fig. 12.3 Dynamic brake operation diagram
L
....................................................................................................................... (12.2)
M
23
73
43
13
Speed [r/min]
Fig. 12.4 Dynamic brake time constant
Servo amplifier
MR-E-10A to MR-E-200A
0
t
e
0.045
0.035
0.025
0.015
0.005
Load inertia moment ratio [times]
12 - 3
Time constant
Time
0.04
0.03
202
0.02
0.01
0
0 500 1000 1500
Speed [r/min]
b. HC-SFE series
30
][oz in ]
2 2
][oz in ]
2 2
52
152
102
2000