High Voltage Power Supply - The Spellman CZE2000 0-30KV from 24VDC :-) Very Nice - Page 1
Forum section: electronics / general

author: Fraser
author_rank: Super Contributor
timestamp: September 04, 2015, 01:24:24 pm
content: I have just taken delivery of a lovely little high voltage power supply unit that I stumbled upon recently.The unit is made by the venerable Spellman conmpany of Hauppauge, NY and is designed for applications that require a variable voltage and variable current output with the specification 0-30KV/0-300uA. I do not have an immediate use for it but at £25 delivered, I could not resist it.It appears very similar to the HV power supplies commonly found in high performance X-Ray systems and could be employed in that role, albeit within the 300uA current limit.The joy of this unit is its compactness combined with ease of control. It requires a 24VDC supply and the V/I output is set using a control voltage range of 0-10V on the Vset and Iset control pins. The 0-10V range represents 0-100% of maximum output. Nice and simple. It also has the surprising capability of a 'HOT' switchable output polarity. That is to say its output can go from +30KV to -30KV in less than a second, under the control of the polarity select pin. Pretty neat capabilityI removed the cover on the unit and it appears to be in great condition inside. The HT section is encapsulated in a silicon insulation as would be expected in a compact 30KV supply. I will not be delving into the encapsulated section and it is likely just a ferrite cored HV transformer and rectifier diode pack anyway.The unit even came with its HV cable and special connector.... joyEnjoy the pics, though sadly there is not a great deal to see in these units. Their true beauty is in their small size, ease of use and the many HV related applications to which they may be applied. Not bad for £25I also attach the data sheet for those interested in the specs etc.Aurora

author: Fraser
author_rank: Super Contributor
timestamp: September 04, 2015, 01:25:42 pm
content: Datasheet attached

author: TimFox
author_rank: Super Contributor
timestamp: September 04, 2015, 09:47:00 pm
content: Spellman HV supplies are very popular with medical x-ray manufacturers, among others.They build rotatable (several revolutions per second) supplies for medical CT scanners.One of their core competences is high-voltage encapsulation.Many decades ago, as a starting graduate student, I was handed an ancient (pre-encapsulation) Spellman 100 kV vacuum-tube power supply and told to reverse the polarity. Four 6146s in parallel driving the RF primary, controlled with a 6BG6 cathode follower supplying the screens. Since the old vacuum rectifiers were x-ray generators on their own, I swapped silicon diodes with the opposite polarity, totally re-tuned the RF transformer circuit, and added a precision servo with outboard resistive divider. I was very happy later to exchange the butchered vacuum-tube chassis for one of their new (with encapsulation) solid-state supplies.

author: Fraser
author_rank: Super Contributor
timestamp: September 04, 2015, 10:39:46 pm
content: Tim,Thanks for the comment.Interestingly, this power supply is very similar to that fitted in my Faxitron MX-20 Microfocus X-Ray machine. My MX-20 HV power supply can deliver between 15KV and 35KV at a fixed 300uA. I could in theory use the Spellman unit in the Faxitron if the original PSU ever failed. Fortunately I also have a complete spare Faxitron MX-20 cabinet thoughAurora