11 - 4
11. CHARACTERISTICS
11.3 Dynamic brake characteristics
Fig. 11.3 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(EM1) 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.)