Mitsubishi Electric MR-J2-03B5, Instruction Manual

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10 - 2
10. CHARACTERISTICS
10.2 Dynamic brake characteristics
Fig. 10.2 shows the pattern in which the servo motor comes to a stop when the dynamic brake is operated.
Use Equation 10.1 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. 10.3)
V
0
Time constant
Forced stop(EM1)
OFF
ON
Machine speed
t
e
Time
Fig. 10.2 Dynamic brake operation diagram
L
max
60
V
0
J
L
J
M
t
e
1
....................................................................................................................... (10.1)
L
max
: Maximum coasting distance .................................................................................................[mm][in]
Vo : Machine rapid feedrate ......................................................................................... [mm/min][in/min]
J
M
: Servo motor inertial moment................................................................................. [kg cm
2
][oz in
2
]
J
L
: Load inertia moment converted into equivalent value on servo motor shaft..... [kg cm
2
][oz in
2
]
: Brake time constant ........................................................................................................................ [s]
t
e
: Delay time of control section........................................................................................................... [s]
(There is processing delay time of about 3.5ms.)
0
0.0005
0.001
0.0015
0.002
0.0025
0 100 400 700 1000 1300 1600
HC-AQ0135
HC-AQ0335
1900 2200 2500 2800 3000
HC-AQ0235
T
im
e
const
ant
[
s
]
Speed [r/min]
Fig. 10.3 Dynamic brake time constant