Turbomolecular pump driver PSU

[ChristofferB]

Hey all! I'm delving into some ultra high vacuum projects, and I'm currently trying to build a vacuum system controller based on my Edwards EXT255H turbo pump.

It comes with a controller doing all the motor drive/speed monitoring stuff, but this controller needs a REALLY oddball 70-85 VDC in... at 2.2A max

How does one accomplish 70-85V 2.2A easiest? Here are the two options I have considered so far:

-serial connected 24V + 48V SMPS modules (=72V, and all control and vacuum gauges and relay logic needs 24V too)

-230->50VAC transformer, then rectification to give roughly 70V.



Using switchmode modules is easier, but I'm unsure if they actually CAN be put in series like that. Also, it might not be ideal to also power relay inputs, buttons, gauges and so from the motor PSU.

Using a linear PSU has the same drawback it always has: heavy and expensive. Also If I could minimize the amount of mains voltage work I need to do I'd be happy.



thanks in advance!

--Chris

[langwadt]

Hey all! I'm delving into some ultra high vacuum projects, and I'm currently trying to build a vacuum system controller based on my Edwards EXT255H turbo pump.

It comes with a controller doing all the motor drive/speed monitoring stuff, but this controller needs a REALLY oddball 70-85 VDC in... at 2.2A max

How does one accomplish 70-85V 2.2A easiest? Here are the two options I have considered so far:

-serial connected 24V + 48V SMPS modules (=72V, and all control and vacuum gauges and relay logic needs 24V too)

-230->50VAC transformer, then rectification to give roughly 70V.



Using switchmode modules is easier, but I'm unsure if they actually CAN be put in series like that. Also, it might not be ideal to also power relay inputs, buttons, gauges and so from the motor PSU.

Using a linear PSU has the same drawback it always has: heavy and expensive. Also If I could minimize the amount of mains voltage work I need to do I'd be happy.



thanks in advance!

--Chris

https://www.west-l.ru/uploads/uf/2a0/2a088acbd4731817651179f5b54b7aa0.pdf

[ChristofferB]

Good resource, thanks! Switchmodes it is, it seems.

[Zoli]

Good resource, thanks! Switchmodes it is, it seems.

Careful with the pre-made SMPS's: some of them has the ground hardwired to the minus.
If you connect two of those in series, the lower unit output will be shorted - always get a proper and detailed datasheet.