Brochure

ESG
8.618.61
8.618.61
8.61
Reversing motor drive for dc Motors
(Fig. 18) (Fig. 18)
(Fig. 18) (Fig. 18)
(Fig. 18)
In this configuration, four dc SSRs are used for motor reversal from a single power supply. The time delay before
enabling the drive in either direction must be greater than the SSR turn-off time to preclude the possibility of a
hazardous make before break condition. Internal reverse diodes or zeners in the SSRs will suppress inductive tran-
sients across the low impedance of the power supply. If no internal suppressors exist, a reverse diode should be
installed across each SSR output or, alternatively, SSRs with blocking ratings at least twice that of the supply voltage
may be used. The circuit should be current limited or fused to protect the wiring in the event of a short circuits.
Out
DC
SSR1
In
+–
Out
DC
SSR2
In
+–
+5 VDC
Direction
1 = FWD
0 = REV
Enable
In
DC
SSR3
Out
–+
In
DC
SSR4
Out
–+
Motor
+–+–
–+–+
Time
delay
FWD
(+) +
Off
FWD
REV
Off Off Off Off
On Off Off On
Off On On Off
1 2 3 4
Direction
SSR switching
Fig. 18: Reversing motor drive for DC motors