B-65302EN/01 SPECIFICATIONS FOR THE βiS SERIES 3.SELECTING A MOTOR
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3.2.7 Calculating the Dynamic Brake Stop Distance
The equation for calculating the coasting distance when an
abnormality occurs and the machine tool is stopped by dynamic
braking with both ends of the motor power line shorted (dynamic
brake stop distance) is given below:
Speed
Time
l
2
Vm
l
1
l
3
t
1
t
2
Vm : Rapid traverse rate, mm/sec or [deg /sec]
l
1
: Coasting distance due to delay time t
1
of receiver
l
2
: Coasting distance due to deceleration time t
2
of magnetic contactor (MCC)
l
3
: Coasting distance by dynamic braking after magnetic contactor has been
operated (t
1
+t
2
) is usually about 0.05 [sec].
LNoBNoAJJttVm
LM
××+××+++×= )()()( due distance Coasting
3
22
[deg]][ ormm
J
M
: Motor inertia [kg⋅m
2
] [kgf⋅cm⋅s
2
]
J
L
: Load inertia [kg⋅m
2
] [kgf⋅cm⋅s
2
]
N
O
: Motor speed at rapid traverse [min
-1
]
L : Machine movement on one-rotation of motor [mm] or [deg]
(N
O
/60×L=V
m
)
A : Coefficient A for calculating the dynamic brake stop
distance
B : Coefficient B for calculating the dynamic brake stop
distance
For details of A and B, see the table on the following page.
For J
M
, see the data sheet of each motor.
There are two ways of shortening this dynamic brake stop distance:
Emergency stop distance shortening function, and emergency stop
distance shortening function effective also during power interruptions
(additional hardware is required).