Search found 27 matches

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: 344

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: 4751

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: 4751

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: 4751

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: 4751

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...
by Chris Giles
Sat Sep 14, 2019 4:29 pm
Forum: Vacuum Technology (& FAQs)
Topic: Turbomolecular pump troubleshooting (EXT255H with EXDC80)
Replies: 44
Views: 4751

Re: Turbomolecular pump troubleshooting (EXT255H with EXDC80)

Hi Arun are all of those figures measurements or programming settings? With power supplies that allow you to set the current and voltage they can run in constant voltage or constant current mode and this may not be obvious. The settings work as limits, i.e.: - if you set the current at a value lower...
by Chris Giles
Sun Aug 11, 2019 9:31 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Fusion Success with Precipitator Power Supply
Replies: 31
Views: 6933

Re: Fusion Success with Precipitator Power Supply

An example: http://www.ti.com/lit/ds/symlink/tl494.pdf If you want to identify the chip, I suggest finding out which are the VCC and GND pins and matching that to various 16-pin controller ICs - look for the most common / cheapest ones. Once you have identified the chip then you would stand a better...
by Chris Giles
Sat Aug 10, 2019 10:07 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Reforming capacitors in consumer electronics?
Replies: 5
Views: 2125

Re: Reforming capacitors in consumer electronics?

Hi Rich, there are two types of caps which might need replacing: 1. the 'X' and 'Y' caps which are on the AC line input as a filter. 2. the electrolytic smoothing caps on the DC lines to the amp If #1 fails they can explode, see here for instance. However, that mainly seems to affect the common type...
by Chris Giles
Sun Mar 31, 2019 7:23 pm
Forum: Vacuum Technology (& FAQs)
Topic: Micro-Ion ATM gauges on eBay
Replies: 10
Views: 7065

Re: Micro-Ion ATM gauges on eBay

I sent the seller information on how to check the filaments I see in the manual for the 354 gauge that it shows you can check the two filaments are 0.2 Ohms and the Grid 0 Ohms (p43 of service manual). I haven't got round to using my gauge yet (RS485 bit of a pain & I dont have my high vacuum stage...
by Chris Giles
Fri Mar 29, 2019 10:48 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: What vacuum chamber do I use?
Replies: 20
Views: 11628

Re: What vacuum chamber do I use?

Hi Brandon, on mine, I have recently got a 4.5" CF cross. From the above discussion it seemed like a good compromise. Now I am on the lookout for further HV parts to piece it all together. The conflat parts certainly are expensive and/or rare with the 4.5" and larger a lot more so than 2.75". My nex...