11 - 4
11. CHARACTERISTICS
11.3 Dynamic brake characteristics
Fig. 11.4 shows the pattern in which the servo motor comes to a stop when the dynamic brake is operated.
Use Equation 11.2 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 Fig. 11.4)
V0
Time constant
Forced stop(EMG_ ) OFF
ON
Machine speed
teTime
Fig. 11.3 Dynamic brake operation diagram
Lmax 60
V0JL
JM
te1.......................................................................................................................(11.2)
Lmax : Maximum coasting distance.................................................................................................[mm][in]
Vo : Machine rapid feedrate......................................................................................... [mm/min][in/min]
JM: Servo motor inertial moment.................................................................................[kg cm2][oz in2]
JL: Load inertia moment converted into equivalent value on servo motor shaft..... [kg cm2][oz in2]
: Brake time constant........................................................................................................................ [s]
te: Delay time of control section ..........................................................................................................[s]
(There is internal relay delay time of about 30ms.)