Permissible Load To Motor Inertia When The Dynamic Brake Is Used - Mitsubishi Electric MELSERVO-J4 Instruction Manual

8. CHARACTERISTICS
V
0
t +
L = •
max e
60
L : Maximum coasting distance [mm]
max
V : Machine's fast feed speed [mm/min]
0
J : Moment of inertia of the servo motor [× 10
M
J : Load moment of inertia converted into equivalent value on servo motor shaft [× 10
L
τ: Dynamic brake time constant ················································································································ [s]
t : Delay time of control section ················································································································ [s]
e
For 7 kW or lower servo, there is internal relay delay time of about 10 ms. For 11 kW to 22 kW servo,
there is delay caused by magnetic contactor built into the external dynamic brake (about 50 ms) and
delay caused by the external relay.
(2) Dynamic brake time constant
The following shows necessary dynamic brake time constant τ for equation 8.2.

8.3.2 Permissible load to motor inertia when the dynamic brake is used

Use the dynamic brake under the load to motor inertia ratio indicated in the following table. If the ratio is
higher than this value, the dynamic brake may burn. If there is a possibility that the ratio may exceed the
value, contact your local sales office.
The values of the permissible load to motor inertia ratio in the table are the values at the maximum rotation
speed of the servo motor. The value in the parenthesis shows the value at the rated speed.
J
1 + L
··············································································································· (8.2)
J
M
100
80
60
2024
40
5024
20
1524
0
0 500 1000 1500 2000 2500 3000
Speed [r/min]
HG-SR series
120
100
80
9034
60
40
5034
20
2034
0
0 1000 2000 3000 4000 5000 6000
Speed [r/min]
HG-SR3000r/min series
-4 2
kg•m ]
524
3524
1024
7024
7034
534
1034
3534
1534
734
8 - 6
-4
kg•m
50
45
11K1M4
40
35
30
22K1M4
25
20
15
10
5
0
0 500 1000 1500 2000 2500 3000
Speed [r/min]
HG-JR1500r/min series
2
]
15K1M4