Mitsubishi Electric MELSERVO-J3W Series, Инструкция по эксплуатации

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15. MR-J3W-0303BN6 SERVO AMPLIFIER
15 - 55
(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 varies with the servo motor and machine operation speeds. (Refer to (2) of this
section.)
V
0
OFF
ON
Machine speed
t
e
Time
Forced stop (EM1)
Dynamic brake
time constant
Fig. 15.2 Dynamic brake operation diagram
L
max
60
V
0
J
L
J
M
t
e
1
......................................................................................................................(15.1)
L
max
: Maximum coasting distance ......................................................................................................... [mm]
Vo : Machine's fast feed speed ..................................................................................................... [mm/min]
J
M
: Moment of inertia of the servo motor...............................................................[ 10
-4
kg m
2
][oz in
2
]
J
L
: Load inertia moment converted into equivalent value on servo motor shaft
··························································································································[ 10
-4
kg m
2
][oz in
2
]
: Dynamic brake deceleration ..............................................................................................................[s]
t
e
: Delay time of control section..............................................................................................................[s]
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.
0
Speed [r/min]
0 1000 2000
0.0005
0.0010
0.0015
0.0020
0.0025
3000 4000 5000 6000
0236
0336
0136
Ti
me
co
ns
ta
n
t
[ms
]
HG-AK series