The Critical applications where availability of continuous power supply is required can be met with hot swappable/redundant 24 vdc power supply. This is useful for increasing the availability of system and enhancing the system performance.
System description:
There are various critical applications in  control systems and field locations where standalone 24 vdc power supplies are used. Any failure in the 24 Vdc power supply being used in the panel results in system downtime related accessories like solenoid valves , actuators not getting the power .
The power system failure thus is not desirable for such panels which are having critical applications like bag filters, casting machine panels, environmental application panels.
Proposed solution 1:
Redundant hot swappable dual power supplies can be seen as a low cost solutions for such  situation .The dual power supplies has 2 set of independent power circuits and in which two power supplies are running in parallel, redundant mode in event of failure of single power supply, other power supply will continue to supply full load. As soon as the 1st power supplies fails by any reason the other one takes over and the operation of the system is not disturbed .(The logical diagram is indicated in fig)
Such  hot swappable redundant power supplies in different voltages range are available in market(,here we are limiting our discussion for 24 vdc power supply for illustration purpose.)
The modification can be seen as a good improvement for the panels utilizing the power supplied for critical applications in continuous running machines,power plants, oil & gas, Refineries, chemical plants, fertilizer plants etc., where stoppage of plant will result in big loss.
Proposed solution 2:
The redundant power supplies can be used with diode unit so that if any unbalanced or short circuit happens in any unit and it will not effect the healthy unit. So always power will be available for the output element.
Note: The Control Modules are controlled by a controller / DCS / PLC systems and this part was not shown in above examples.
Article Written by:Â
Sh. Pravin V. Maheshkar
Management & technical consultant/trainer Freelance
Previously Manager –Inst & Business excellence
(Hindustan zinc ltd ,Echjay steels ltd,total:23 yrs)
