Product specifications
Power Supply Units – Types SD821, SD822 and SD823 Appendix A Hardware Units
360 3BSE036351-510 A
The output voltage of all three PSUs is a regulated, low noise, 24 V DC. A green
LED on the PSU front panel indicates that the output circuit is providing the correct
output voltage level. The double connectors provided on the 24 V DC output
terminals allow for connecting more than one piece of equipment.
A surge current limiter within the PSU circuit provides a soft-start feature.
Consequently the controlled power-on of a PSU will not trip fuses or ground-fault
circuit breakers. In addition, the normal disturbances that occur within an industrial
main network will not result in transient fault conditions or tripping.
This results in the surge current limiter effectively reducing the peak inrush current
caused by a power disruption, to a level the PSU can tolerate.
This soft-start, surge current limiter facility simplifies designing the system power
distribution circuits.
Insulation of Power Supply Units (PSU)
Basic with protective conductor; primary circuit separated from all other live
circuits by reinforced insulation.
Rated insulation voltage, Primary to Secondary 300 V AC.
Figure 91. PSU’s SD821, 822 and 823 – Block Diagram
L
N
PE
L+
L+
L–
L–
Chopper
Fuse
X1
X2