LaserUser.com Forum (formerly RDWorksLab)

Post by Gene Uselman » Fri Sep 30, 2016 11:52 am

My suggestion for you Bodor people is to
1. Get high voltage cable , check to see if the cable is 40kv or better. If it is, try extra insulation around the cable from source to tube.
2. Look at your lead dress. Keep the HIGH VOLTAGE cable away from all other cables including grounds. If the feed through hole to the tube is not very big, make it bigger and put a grommet in the hole and then run the cable back through the hole.

That should fix your problems.

This is me-
I was actually working on this yesterday- I made 1" standoffs from pvc water tubing to get the cable away from anything metal, ran the cable through a 2.5 foot length of 3/8" gas line (2 layers of rubber with a fabric layer in the middle), wrapped the tube to position the HV wire along the side of the enclosure with the most room and wrapped the metal knob on the end of the tube where the wire attaches with the same high voltage tape that fuses together. Then the rubber sleeve that Bodor sent along. I just put in the 3rd power supply but have not had a chance to test yet. Gene

Hi ,
I have a large 150w BODOR and I am curious what problem this is fixing?

shorts to ground from the high voltage lead

'Some' Chinese origin wire is not what it should be and the insulation breaks down causing either just a very low current capacitive leak or in some cases an actual spark through it when that has happened it is like an open path from then on and voltage always takes the path of least resistance. This can be started by anything from poor manufacture to a knick in it during construction or even something you have done. 15-20kV has the ability to jump a gap in air of about 1kV/mm so 15-20mm so in theory the standoffs will help but better undamaged cable is the answer.

A 'reasonable' wire to replace it with is this Evilbay 40kV wire

Or if you know someone that deals with Gas Boilers or Heaters then they should have some better quality wire for the spark igniters. The Neon Sign industry is also a good source.

Boy- that was a long time ago. The actual problem I was having was the HV crossing over to the control circuit and causing mayhem. It was specific to the desktop Bodor that was designed for a shorter tube and then a crude modification was done to use a longer 100w Reci tube. I think the original design was done in Switzerland but the modification was all Chinese and poorly done. This was a common problem with this machine- I was in contact with people all over the world having the same problems. I thought the machine was nicely finished with good parts but adding the larger tube was a fiasco. I know of people who are happy with Bodor lasers. Gene

I wonder if a power leak could be happening to my machine. I've not experienced any shorts but there some scorch marks on the metal cabinets the the HV wire passes along.

Evan Winn wrote: Mon Jun 17, 2019 I wonder if a power leak could be happening to my machine. I've not experienced any shorts but there some scorch marks on the metal cabinets the the HV wire passes along.

I would say you answered your own question - a bit of rubber may be in order to resolve your issue.

Evan Winn wrote: Mon Jun 17, 2019 I wonder if a power leak could be happening to my machine. I've not experienced any shorts but there some scorch marks on the metal cabinets the the HV wire passes along.

Once you have had a Dielectric Breakdown of the insulation on the wire it will tend (not a certainty) to keep happening at that point. Over time depending on the insulators material it can finish up making a carbonised path (some plastics breakdown to Carbon + other) from the copper to you chassis.

As Pete offered re sheathing the cable or better yet replacing it with some better cable like I put a link to above is in order.

Tim Mellor wrote: Mon Jun 17, 2019

Evan Winn wrote: Mon Jun 17, 2019 I wonder if a power leak could be happening to my machine. I've not experienced any shorts but there some scorch marks on the metal cabinets the the HV wire passes along.

Once you have had a Dielectric Breakdown of the insulation on the wire it will tend (not a certainty) to keep happening at that point. Over time depending on the insulators material it can finish up making a carbonised path (some plastics breakdown to Carbon + other) from the copper to you chassis.

As Pete offered re sheathing the cable or better yet replacing it with some better cable like I put a link to above is in order.

Out of curiosity, I wonder if spark plug wires would work well. They're designed for very high voltages.

Sparkplug leads vary and a lot of them are not necessarily copper conductors (noise suppression reasons). The insulation will almost certainly be fine for small Lasers however.