Redundant 48 Volt Power Supply - Part 2 - Wiring up the Rack and PSU

Now comes the all important job of wiring up the rack mounted power supply units.

This part of the project requires heaps of wire, a soldering iron, connectors and a steady hand.

Important WARNING - The next part is for informational and academic use only. This system uses dangerous and lethal voltages. Only qualified and experienced technicians should work on high voltage power supply systems.

Wire up all the internals with the appropriate cable types and colour coding. It is important to use the correct wire types and colours for the 240AVC and 48VDC circuits. All the wire ends were soldered onto connectors or terminals and all exposed connections covered in heat shrink tubing. Also, the yellow grounding cable to the rack casing was securely attached to the earthing connector on the case.

The PSU & rack all wired up

Below is a diagram showing the PSU wiring in the 2ru rack case. With 240VAC mains power coming into the PSU unit and the clean 48VDC power being delivered out of the unit. 

Parts list per PSU circuit:

1x 3700K Resistor 1x LED with mount 1x 240VAC fuse holder 1x IEC socket with mount

1x DC power socket with mount 1x Ceramic fast blow fuse 1x Switch (Suitable for 240VAC) Loads of wire for 240 volt and 48 volt Applications

Below are images of the front and back panels. On the front panel is mounted the power switch, red LED and DC power connector socket. On the back is the IEC power socket for the 240 volts AC cord connection and the fuse holder with a quick blow ceramic fuse.

Close-up of the front of the rack

Close-up of the back of the rack

Now the task remaining was to make up the DC power cables and test the PSU units before turning them on (I used my multimeter all the way though the building process, which is good practice).

Everything looked good and I was ready to test with mains power and a heavy load on the DC outputs.

DC Power Cables

Testing the PSU racks

Put the tops back on and plug them in.

Test the DC voltage and ensure everything is fine at 48.2 VDC. No leaks or other obvious problems.

All done, with two redundant 48 VDC power supplies ready to be shipped out. (I also had another technician check it over).

PSU all finished front view

PSU rack all finished back view

Stay tuned to Burning the Midnight for the next and final part of this project.

I will be mounting the rack unit and connecting up the redundant power supply to a Longreach X-Band wireless backhaul.

More fun and excitement.