50 kW Sedecal SHF-530 X-ray High Voltage Generator Inverter Teardown

This Sedecal SHF-330, with HF meaning High Frequency, was originally a 37.5 kW x-ray high voltage generator. It later received an upgrade, to a Sedecal SHF-530, which is a 50 kW 500mA x-ray high voltage generator. This x-ray generator comes in 3 different versions. Line powered drawing all power directly from mains, 20-50 kW. Capacitor assisted drawing most power from a capacitor bank, and power directly from mains, when charged up, is 2.2 kW. Battery supplied unit that needs a recharge, but can operate completely free of mains supply for a given amount of pictures taken.

If you like to see more teardowns, I can firstly recommend checking out the complete list of teardown videos and articles. Secondly, if you are only looking for x-ray related information and teardowns, check out the following.

Sedecal SHF-530 Parts

The system construction is very similar between small and large, and old and new systems. This is typical for medical systems, as making a proven and tested system, that gets validated for medical use, can be very time consuming and thus expensive. This is properly a reason for the very modular construction with controller board, relay board, power supply boards, inverter plate and high voltage tank.

The 3 phase full bridge rectifier and PM300DSA120 inverter is installed on isolated standoffs. This whole construction is mid point grounded to the high voltage tank, which has a maximum output voltage of 125 kV peak.

The HT Controller A-3000-10 uses primarily ADC and 74HCxx logic ICs and a single 40-pin DIP microcontroller running at 10 MHz.

I salvaged many different parts from this inverter. As it is all modular and uses off the shelf components, its very easy to take apart and reuse. The isolation transformer is 230VAC to 115VAC, plus other voltages and properly around 2 kVA. The Line filter is with a 37.5 kW power rating. The Trobo 3700uF 450 VDC electrolytic capacitors could be the most fragile part to ageing damages. The PMB 2uF 1000VDC snubber capacitors are always great for something else.

The Semikron SKKD 40F10 double diode modules, are great for any kind fo rectifier bridge, with their 1000V and 40A rating. The Mitsubishi PM300DSA120 IGBT power modules are a CM300 brick with built-in protection and driver circuit. This unfortunately also limits it to a 20 kHz drive frequency, which is unsuitable for Tesla coil inverters. Maybe the internal driver can be bypassed, like when I cut out the RTC of a CM600 IGBT.

Read more at Kaizer Power Electronic's Blog

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