Rods "Spaceship" Scratch built Plasma Cutter build

Well, it looks like the spaceship is getting a downdraft table. I always wanted to go that way. I scored a free multicam router dust extraction fan which supposedly had a burnt out motor at the business next door.



But 15 minutes after we got it the 10 metres home back into our workshop, we diagnosed the fault as being a burnt out switch! Sure enough when we bypassed it,it sprang to life. I had a big heavy duty switch at home which we managed to install into the existing switch housing so we have a permanent repair!


This is a metal fan with a 3 hp 15 amp single phase motor with about 2000 CFM and a 6" inlet

It also has a 3 way 4" inlet splitter but I don't think we will use it.


Today I thought I better get it over near the plasma and see how it might go together.


This might actually fit in OK. There is just enough room to get the outlet out from under the table but I have no clue what to do then!





So under the table it looks like this



I think if I make up a manifold out of some 6" tube that includes a T piece part way along and terminated by an elbow, I should be able to make a zoned downdraft table and keep all of the mechanisms outside of the dirty area.

I need to do a bit of thinking about this...

If you turn 90 degree along the motor axle and mount from the side the outlet will have enough room for the exhaust

Mike_Eitel wrote: If you turn 90 degree along the motor axle and mount from the side the outlet will have enough room for the exhaust

Yeh I've thought about that which is why I put it down beside the plasma cutter so I can see different ways to do it. There is a bit to consider to keep the duct work easy to fabricate.

As an aside and its not a very good photo but this pic shows a 30mm square piece of 2mm steel held hard against the table frame by air pressure. Its 160mm above the outlet so the fan shifts some air!

Looking on the picture with text "This might... ". Turn 90 degree conter clockwise. You have posibilities enough to go either straight to the left or via 90 tubes along table etc..
m5c
Mike

And they use supercooled stuff to levitate things ....

Well had a strange thing happen today when doing a quick cut of a prototype. I noticed the torch voltage was fluctuating wildly. I checked the encoder velocity pin in halshow and it was doing likewise. I grabbed a multimeter to check the plasma cutter voltage input at the THCAD when not cutting and noticed the plasma interconnect cable shield had become dislodged from the THCAD. The voltage seemed stable by the multimeter. I connected the shield and things seemed to settle down. Proceeded to cut and then had a massive crash into the material and I noticed it was fluctuating wildly again. I went to grab my phone to take a quick video and when I came back it was stuck on 44 volts (or was that -44). Checked the encoder velocity and it was zero. Rebooted the machine and power cycled the control box as well. Also disconnected and reconnected the THCAD input. Then checked the encoder velocity and it was perfect on the zero volt frequency.

That was at the end of the day so I will review all the connections again tomorrow when I have a bit more time. I have a spare THCAD here so I might try that if it continues. I think its definitely an electronic issue so will investigate further to get to the bottom of it.

I vaguely recall someone reporting a similar issue recently. If you have any ideas, please let me know.