Dynamic Brake Characteristics; Dynamic Brake Operation - Mitsubishi Electric MR-J2S-CP Instruction Manual

13. CHARACTERISTICS

13.3 Dynamic brake characteristics

13.3.1 Dynamic brake operation

(1) Calculation of coasting distance
Fig. 13.3 shows the pattern in which the servo motor comes to a stop when the dynamic brake is
operated. Use Equation 13.2 to calculate an approximate coasting distance to a stop. The dynamic
brake time constant
section.)
Forced stop (EMG)
J
V
0
L t
1
e
max
60
J
L : Maximum coasting distance .................................................................................................[mm][in]
max
V : Machine rapid feed rate ........................................................................................ [mm/min][in/min]
0
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.)
(2) Dynamic brake time constant
The following shows necessary dynamic brake time constant for the equations (13.2).
16
14
12
10
8 053
6
4
2
0
0 500 1000 1500 2000 2500 3000
a. HC-KFS series
varies with the servo motor and machine operation speeds. (Refer to (2) of this
ON
OFF
V
Machine speed
Fig. 13.3 Dynamic brake operation diagram
L
....................................................................................................................... (13.2)
M
23
73
43
13
Speed [r/min]
0
t
e
0.02
0.018
0.016
0.014
0.012
0.01
0.008
0.006
0.004
0.002
0
13 - 4
Time constant
Time
23
0 500 1000 1500 2000 2500 3000
Speed [r/min]
b. HC-MFS series
][oz in ]
2 2
][oz in ]
2 2
73
053
43
13