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9. CHARACTERISTICS
(2) Electromagnetic brake power supply
24VDC of the internal power output for interface (VDD) cannot be used. Prepare the following power
supply for use with the electromagnetic brake only. Examples of connection of the brake exciting
power supply are shown in Fig. 9-2 (a) to (c). (a) is for AC off, and (b) and (c) for DC off. When DC is
switched off, the braking delay time will be shortened, but a surge absorber must be installed on the
brake terminal. For the selection of the surge absorber, refer to Section 6-2-5.
28V AC
100V AC
or
Switch
200V AC
T
24VDC
(3) Coasting distance
At an emergency stop, the servo motor will decelerate to a stop in the pattern shown in Fig. 9-4. Here,
the maximum coasting distance (during fast feed), Lmax, will be the area shown with the diagonal line
in the figure and can be calculated approximately with Equation 9-2. The effect of the load torque is
greater near the stopping area. When the load torque is large, the servo motor will stop faster than the
value obtained in the equation.
Electromagnetic
RF
brake
(a)
Electromagnetic
brake
Switch
VAR
(c)
Fig. 9-2 Connection Examples
Emergency stop
Brake current
Machine speed
V
0
Fig. 9-3 Coasting Distance at Emergency Stop
100V AC
or
200V AC
T
T
: Transformer
RF
: Rectifier
VAR
: Surge absorber
t
t
t
1
2
3
9 - 7
Electromagnetic
RF
brake
Switch
VAR
(b)
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