Dynamic Brake Characteristics; Dynamic Brake Operation - Mitsubishi Electric Melservo-J3 Series MR-J3-B Instruction Manual
Melservo j3 series general-purpose ac servo sscnet compatible
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Also See for Melservo-J3 Series MR-J3-B:
- Instruction manual (802 pages) ,
- Manual (668 pages) ,
- Handbook (590 pages)
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10. CHARACTERISTICS
10.3 Dynamic brake characteristics
10.3.1 Dynamic brake operation
(1) Calculation of coasting distance
Fig. 10.3 shows the pattern in which the servo motor comes to a stop when the dynamic brake is operated.
Use Equation 10.2 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)(a), (b) of this section.)
Forced stop(EM1)
J
V
0
L
t
1
e
max
60
J
L
: Maximum coasting distance .................................................................................................... [mm][in]
max
Vo
: Machine rapid feed rate ..............................................................................................[mm/min][in/min]
J
: Servo motor inertial moment..................................................................................... [kg cm
M
J
: Load inertia moment converted into equivalent value on servo motor shaft ............ [kg cm
L
: Brake time constant .......................................................................................................................... [s]
t
: Delay time of control section............................................................................................................. [s]
e
For 7kW or less servo, there is internal relay delay time of about 30ms. For 11k 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.
(2) Dynamic brake time constant
The following shows necessary dynamic brake time constant for the equations (10.2):
(a) 200V class servo motor
25
20
15
73
10
5
0
0
1000 2000
HF-MP series
ON
OFF
V
Machine speed
Fig. 10.3 Dynamic brake operation diagram
L
....................................................................................................................... (10.2)
M
23
43
053
13
3000 4000 5000 6000
Speed [r/min]
0
t
e
25
20
15
10
5
0
10 - 6
Time constant
Time
73
23
053
13
43
0
1000 2000
3000 4000 5000 6000
Speed [r/min]
HF-KP series
2
2
][oz in
]
2
2
][oz in
]
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