A few questions setting up our new Shenhui lasers.

[Scott Moore2]

I had arcing all over my 100w Morntech. I know it's a different brand, but the same sort of cheap Chinese knock off. I had arcing in a couple of spots. I eventually rubber lined the box the tube sits in with a sticky backed rubber flashing underlayment. Then I put silicon on the leads to the AMP meter, and on all the connections throughout the machine. What I found was that the wiring was not sufficiently covered and protected from arcing in about a half dozen places. The wires connecting to the bulb were only one thing to solve.

[Uros Sovilj]

Hi

The silicon is for sealing HV conection on Tube. If you don't seal HV contact where red wire comes from Tube power suply to tube connector the spark will hitting the housing of the machine and will destroy your tube plus it can be dangerous to you if you don't have propper grounding. Just put silicon on contact and form a big bulb with fingers. You also have sticky thread on shenhui lasers just on the top of thread list.
Note that normal insulated tape wont work as said in this thread before you need to have Hihg voltage tape but silicon you have works ok.

[Rich Harman]

I did not use the silicone or any other type of insulation, other than the plastic cap that goes over the HV connection to the tube, and I have not had any arcing.

[Uros Sovilj]

Did happen to meDSCF6569.jpg

[Nick Foley]

Thanks for the note about sealing the HV connection! Pretty wild that it arced that far.... I guess the 19 kV ignition voltage of the tube means a potential arc length of ~19mm.

Speaking of the wiring:
What are my options for grounding the (110v, 90W RECI) machine? I'm setting ours up in an area where a "meter long copper spike in the ground" simply isn't feasible. Are there viable alternatives? A solid connection to the outlet ground wire perhaps?

[Nick Foley]

Update:

Connected the frame of my laser to my outlet box ground, seems to be working so far.

[ray hampton]

Update:

Connected the frame of my laser to my outlet box ground, seems to be working so far.

did you check your ground wire to made sure that it are actual making contact at all points

[Greg Facer]

ugh,

second replacement (this time in a wooden crate) via DHL air arrived damaged.....quite a bit worse than the one shipped only in the cardboard box....ie internals smashed to bits.

Another month down the tube with this machine! I guess I was wrong not to buy a spare tube.....might try to get one off ebay as a spare and while I wait again. unless anyone has got a shipment coming by ocean that I can hitch a ride on.

Greg

[Rich Harman]

I have a spare 80 watt Reci tube and power supply. Let me know if you need it.

[Greg Facer]

Hi Rich

Think I might hook up replacement #1 and see what happens. Near as I can tell, the break on that one only makes the coiled section of glass shorter.....much shorter. But, that section of glass seems to only be to pull in more CO2 to the laser chamber.....maybe the coil is to prevent condensation?

Anyways, might work in a pinch.....any larger jobs I can use the other machine for, especially when I have the speed / power figured out....thanks for the offer though.

DHL is NOT on my favorites list. Not very effective customer service, and not very good handling procedures obviously.......might have to send a few shock labels to stick on the box to RECI.

[Greg Facer]

I just saw a post from Ray Scott of Rabbit laser on CNC zone...... the coil is for making the path longer than the central tube....arcing will almost certainly occur through the outer tube if I hooked it up.

FYI for anyone in the same position. Think it's time to toss the tube in the trash.

[Davis McCarty]

Hi

The silicon is for sealing HV conection on Tube. If you don't seal HV contact where red wire comes from Tube power suply to tube connector the spark will hitting the housing of the machine and will destroy your tube plus it can be dangerous to you if you don't have propper grounding. Just put silicon on contact and form a big bulb with fingers. You also have sticky thread on shenhui lasers just on the top of thread list.
Note that normal insulated tape wont work as said in this thread before you need to have Hihg voltage tape but silicon you have works ok.

Do you have a photo of how to do this correctly? |
My laser was running without issue for about 2 days, then we had a severe arcing issue, causing the plastic cap on the 130w laser to melt due to fire. Since then I have added a electrical line conditioner and grounded the machine. On my tests last night I was still seeing arching while pulsing.
I have a dual 130w & 80w in the same machine. The 80w is also now arching in my pulse tests. I will recheck my wiring and look for any unsealed/loose connections tonight.

Davis

[Bill George]

FYI Once the HV starts arcing it leaves a carbon track which it will follow the next time. Go to a good automotive parts store and get the copper core HV spark plug 8mm wire meant for modern CDI ignition systems, rated at about 40,000 volts, use it and new connectors and boots meant for spark plug use.
Making 100% sure the tube is grounded and all ground points are clean and tight. Adding extra jumpers for good ground connections will help. IF the tube is not grounded back to the PS then the HV + will be hard to control.