Mitsubishi Electric MELSERVO-J3W Series Instruction Manual page 460

15. MR-J3W-0303BN6 SERVO AMPLIFIER
(1) Dynamic brake operation
(a) Calculation of coasting distance
Fig. 15.2 shows the pattern in which the servo motor comes to a stop when the dynamic brake is
operated. Use equation 15.2 to calculate an approximate coasting distance to a stop. The dynamic
brake time constant
section.)
V
0
L t
e
max
60
L : Maximum coasting distance ......................................................................................................... [mm]
max
Vo : Machine's fast feed speed ..................................................................................................... [mm/min]
J : Moment of inertia of the servo motor............................................................... [ 10
M
J : Load inertia moment converted into equivalent value on servo motor shaft
L
·························································································································· [ 10
: Dynamic brake deceleration ..............................................................................................................[s]
t : Delay time of control section..............................................................................................................[s]
e
The processing delay time about 3.5ms.
(b) Dynamic brake time constant
The following shows necessary dynamic brake time constant τ for equation 15.1.
varies with the servo motor and machine operation speeds. (Refer to (2) of this
Forced stop (EM1)
Machine speed
Fig. 15.2 Dynamic brake operation diagram
J
L
......................................................................................................................(15.1)
1
J
M
0.0025
0.0020
0.0015
0.0010
0.0005
0
0
ON
OFF
V
0
0136
0236
0336
1000 2000 3000 4000 5000 6000
Speed [r/min]
HG-AK series
15 - 55
Dynamic brake
time constant
t
e
-4
kg m
-4
kg m
Time
2 2
][oz in ]
2 2
][oz in ]