Search found 32 matches

by Chris Giles
Sun Sep 06, 2020 10:33 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Questions about HV rectifier
Replies: 35
Views: 3350

Re: Questions about HV rectifier

Hi Tony, As Dennis said, you must ground the chamber and indeed all metal components. In order to achieve this, put the current shunt resistor in the PSU, NOT in between the chamber and ground. I've shown the three different rectifier configurations. This results in the positive side of the rectifie...
by Chris Giles
Tue Sep 01, 2020 7:51 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Questions about HV rectifier
Replies: 35
Views: 3350

Re: Questions about HV rectifier

Much better explanation Rich :)

Tony, do you have a transformer already?
by Chris Giles
Tue Sep 01, 2020 6:06 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Questions about HV rectifier
Replies: 35
Views: 3350

Re: Questions about HV rectifier

That is full-wave vs half-wave, I'm sure you can find decent references explaining it on the web. Note that in a basic HV PSU (rather than a commercial unit with a 'multiplier'), it is not outputting DC but rectified AC (no smoothing cap required). These differences matter for correctly estimating h...
by Chris Giles
Sun Aug 30, 2020 10:36 pm
Forum: Vacuum Technology (& FAQs)
Topic: Is $180(USD) a good offer for a Pfeiffer TCP 121 turbo controller?
Replies: 5
Views: 1399

Re: Is $180(USD) a good offer for a Pfeiffer TCP 121 turbo controller?

Hi Josh. I can help you out if you want to proceed with this as I have the same unit. Firstly, if you don't buy that particular TCP121, then bear in mind there is also TCP120 which is typically cheaper; its the same electronics but with no front-panel, for use as an embedded controller in larger mac...
by Chris Giles
Sun Jul 19, 2020 4:45 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: HF switcher supply construction and voltage multiplication
Replies: 38
Views: 8568

Re: HF switcher supply construction and voltage multiplication

Hi Pierre, I'd recommend using a dedicated driver IC for this rather than designing it totally from scratch. Earlier in this thread the an Infineon IC is shown. Alternatively you could rip-off large parts of the circuit from a commercial design, for instance see the manual in this post . You might a...
by Chris Giles
Thu Jan 09, 2020 10:43 pm
Forum: Announcements and Site Administration Topics
Topic: Visiting Bay Area 13th-17th Jan
Replies: 1
Views: 1198

Visiting Bay Area 13th-17th Jan

If anyone is around in the Bay Area next week and would like to meet up please let me know. I'll be in Palo Alto.

I'm usually in London, so likewise, if anyone wishes to meetup in London I could usually make that.

Cheers
Chris.
by Chris Giles
Wed Sep 25, 2019 9:58 pm
Forum: Vacuum Technology (& FAQs)
Topic: Turbomolecular pump troubleshooting (EXT255H with EXDC80)
Replies: 44
Views: 10787

Re: Turbomolecular pump troubleshooting (EXT255H with EXDC80)

Hi Arun,

that all sounds good. Are you sure that you have the pinout correct? For instance, try the 2 checks i mentioned before.

regards
Chris
by Chris Giles
Tue Sep 24, 2019 8:52 pm
Forum: Vacuum Technology (& FAQs)
Topic: Turbomolecular pump troubleshooting (EXT255H with EXDC80)
Replies: 44
Views: 10787

Re: Turbomolecular pump troubleshooting (EXT255H with EXDC80)

Hi Arun use your voltmeter to monitor the PSU voltage, i.e. between pin 6, 7. See if it dips noticeably below 80V when you press the start switch. Looks like your PSU is working OK according to your tests. The manual says max current is 1.1A, which could well be when it is first energised. If it is ...
by Chris Giles
Fri Sep 20, 2019 9:10 pm
Forum: Vacuum Technology (& FAQs)
Topic: Turbomolecular pump troubleshooting (EXT255H with EXDC80)
Replies: 44
Views: 10787

Re: Turbomolecular pump troubleshooting (EXT255H with EXDC80)

Hi Arun, please connect your DMM as shown in Rex's diagram and report back what you measure. This is the Output of your DC-DC converter. If you only have one DMM, then you can measure the voltage and current in two separate tests. Leave pin 2 disconnected. Also can you draw a schematic diagram that ...
by Chris Giles
Tue Sep 17, 2019 9:44 pm
Forum: Vacuum Technology (& FAQs)
Topic: Turbomolecular pump troubleshooting (EXT255H with EXDC80)
Replies: 44
Views: 10787

Re: Turbomolecular pump troubleshooting (EXT255H with EXDC80)

Hi Arun, I recommend that you get comfortable with how to measure voltage and current first and experiment with how the voltage and current limit settings work on your PSU(s). You can do this by using some resistors and experimenting with the PSU at low power, say < 10V and < 0.5A. This will be usef...