TVS Progress

30 05 2010

All photos.

Wiring up transient voltage suppression for all channels. I’m using shielded twisted pair for interconnects.





Fire the coils!

30 05 2010

Here is a video of firing the coils:





TVS Test

29 05 2010

All photos from today.

Worked on the transient voltage suppression system all day.

I wired up a single differential channel on the USB 6008 with TVS protection:

The channel seemed to behave normally with the TVS circuit installed. Next is to test it with a voltage spike. Maybe start with this guy:

Simple Labview VI to monitor the voltage:

Also cleaned up the computer cart:





Transient Voltage Suppression

22 05 2010

All photos

I enjoy drawing my schematics on the whiteboard and snapping a quick picture. This is the schematic for transient voltage suppression going into the USB 6008:

Started wiring it up:

The diodes are heavy duty:

The diode’s leads are too thick for the USB 6008 Prototyping board:

I can still solder these diodes on, but it will get crowded on this board:

So I will also use standard prototyping board:





Lab Time

16 05 2010

Spent some time in the lab. Really loving my new photo blogging capabilities. Shoot first, answer questions later.

Friday’s photo stream.

Saturday’s photo stream.

Received a bunch of parts from mouser. Including the protection diodes.

Prototyping board for NI USB 6008. I should have ordered two!

Did a tour of my shop neighbor’s guitar workshop:

Made progress on the coil power supply chassis:

And played around with ferrofluid:





Photo Stream

9 05 2010

I recently acquired a remarkable little piece of technology called eye-fi. Its an SD memory card for your digital camera with built in WIFI. As soon as I take a picture it is uploaded to Picassa and my computer. It’s amazing.

Photography is the most important part of this blog, but until now… the most cumbersome. It was a 10 step process to get a photo from my camera to the blog. Now I am publishing a photo stream just by taking the photos. So easy.

The upshot is I will be publishing about 100 photos every day I’m in the lab… you will literally see them before I do.

So without further ado, here is the new photo stream. And here is a tour of the lab in photos from today. Some highlights:

Picked up a wireless USB hub:





Coil Power Supply 10 Cap Test

8 05 2010

Today I did a full 10 capacitor 450V test fire of the coil power supply into the coils:

No problems, everything went well.

On a disappointing note… it looks like Goddamn vacuum pump is broken again: the vent value going into the turbo pump is stuck open, allowing atmosphere to flow into the chamber. Maybe I fried the valve with a voltage spike.





Transient Voltage Suppression

4 05 2010

When the fusor’s plasma becomes unstable and sparks, it makes my DAQ crash. This is likely due to transient voltage spikes in the wires, or electromagnetic interference through the air.

I’ve been exchanging emails with Raymond R. about the details of voltage suppression. He suggest using TVS diodes to protect each channel of the DAQ from voltage spikes in the wire by clamping them just above  the channel’s operating range.

I’ve ordered these TVS diodes:

1.5KE7.5CA

1.5KE12CA

Raymond suggests the following:

1) Buy the  NI USB-6000 Series Prototyping Accessory if you have the money and want to avoid messiness; otherwise you can kludge the wiring. (I’ve done this).

2) 16 (+ 4,5 spares) of  LCE10A-ND (I bought corresponding parts at mouser).

3) Go to differential mode on NI USB 6008 (good idea).

4) Connect the TVSs from each input/output line to  frame ground.

5) Take the cable shield and do not connect it at the USB board; connect back to the computer frame.  The TVS diodes go to the cable shield not to the USB box grounds.  Connect the USB grounds together and to the shield ground through a 1 meg resistor (alternately a .1 uf ceramic cap).








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