Справочник Пользователя для Mitsubishi Electronics MR-J2S- A
12 - 5
12. CHARACTERISTICS
12.3 Dynamic brake characteristics
Fig. 12.6 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. 12.7. Please contact
us for the servo motor not indicated.)
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. 12.7. Please contact
us for the servo motor not indicated.)
V
0
Time constant
Emergency stop(EMG)
OFF
ON
Machine speed
t
e
Time
Fig. 12.6 Dynamic brake operation diagram
L
max
60
V
0
J
L
J
M
t
e
1
....................................................................................................................... (12.2)
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]
For 7kW or less servo, there is internal relay delay time of about 30ms. For 11kW to 22kW
servo, there is delay time of about 100ms caused by a delay of the external relay and a delay of
the magnetic contactor built in the external dynamic brake.
servo, there is delay time of about 100ms caused by a delay of the external relay and a delay of
the magnetic contactor built in the external dynamic brake.
Speed[r/min]
0
14
16
2
4
8
10
6
12
0
500 1000 1500 2000 2500 3000
13
73
23
43
053
T
im
e
c
o
n
s
ta
n
t
[
m
s
]
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
0.02
0
500
1000 1500 2000 2500 3000
73
23
43
053
13
Speed [r/min]
Ti
m
e
c
o
nst
ant
[
s
]
a. HC-KFS series
b. HC-MFS series
Fig. 12.7 Dynamic brake time constant 1