3 Phase 10 kVA power supply


Below some pictures of the building of my new three phase high voltage power supply.

It was built "just for fun" because with the smaller 3 phase HV power supply the voltage dropped too much to my opinion. I wanted to have a much more stable Anode voltage.



The 3 phase transformer has a weight of 85 kilo, so I did use a removal company (with some strong guys) to get the transformer in my shack on the second floor.

The transformer under test. To measure the idle current per phase and set the taps to the right AC voltage.


The transformer mounted in the 19 inch rack.                                                                              Testing the power supply, using a 3 phase variac. 

The bottom of the rack is replaced by a 12 mm thick aluminum plate in which the 4 wheels are mounted as well.

Without reinforcement the 19 inch rack would not survive the weight.



A closer look at the 6 phase rectifier and bank of capacitors. The PC board on the right contains the Ia sensing circuits, connected to the PIC control circuits by a high voltage opto-coupler . The board in the middle contains the bleeding resistors for the 8 kV voltage meter and voltage surveillance circuit.

The slow-start circuit and main relay.


The main relay can switch 30 A and "overrides" the smaller relay with its 3 voltage ramp-up resistors.

The resistors are overridden by the main relay in approx. 4 seconds

The picture is taken during the test phase, with the variac connected.

At a later stage the 400V /3 phase input power lines were added and the relays properly connected


At the back the DIN-connector to the control circuits
















The finished rack. The 2 meter rack is the one in the middle, with the 3 phase HV compartment at the bottom.


QBL start page