I have a large ferrite bracelet for the output of the VFD to the spindle motor.
The computer is fairly new... I have some Cat-5 and Cat-6 cable and the DB9 looks like a solder type shell. JT On 12/26/2015 11:53 AM, Rafael wrote: > On 12/26/2015 07:16 AM, John Thornton wrote: >> I just checked the ground to housing on the VFD filter, VFD, computer, >> and the smaller filter and they are all internally connected to ground. >> The VFD is controlled via modbus so I don't know how to check that cable >> (which is just a phone cable with a phone jack on one end and a DB9 on > Phone cable? Can you try to replace it with Cat-5 or a better twisted > pairs cable? > >> the other end to connect to the computers serial port, it's a Automation >> Direct cable not home made. > There is one other thing you might want to try, install ferrite core on > power or other cables. It takes a lot of RF noise out. Search for > "Ferrite Core Cord Noise Suppressor" > >> Is injection to the mains coming back to the machine somehow? >> >> JT >> > I opened older power supply for 1U computer to remove the dust recently. > I'm glad I did. Just looking at it, I could tell that there were 3 bad > 3300uF capacitors. Their tops were not flat. PSU still worked with small > motherboard and one disk drive but the power was not clean for sure. > > It is possible that you have a similar problem, i.e. old electrolytic > caps in your VFD or power supply. Very critical in analog circuits. > > Electrolytic caps are the most unstable electronic components and need > to be replaced in old equipment. Some large caps can be refurbished but > that's an extreme situation in very old computer restoration efforts. > > Merry Christmas, > ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
