On Sunday 01 January 2017 23:16:33 Gene Heskett wrote: > On Sunday 01 January 2017 19:01:29 andy pugh wrote: > > On 1 January 2017 at 23:47, Gene Heskett <ghesk...@shentel.net> wrote: > > > Its radiated noise from the motor supplies. > > > > Motor supplies don't even need to be regulated. Just use a > > transformer, rectifier and capacitors. > > > > (transformer might be optional, depending on hardware, both my > > current machines run from rectified mains power) > > That thought is a last resort, mainly due to a profound lack of > suitable transformers after building 2 machines with kilowatt+ iron > powered dc spindles, my junk box is severely depleted. Also the iron > tends to have lots more ohmic power loses. There do not appear to be a > surplus of big iron for sale any more, not like there was half a > decade back. The choices are pretty limited on fleabay tonight just > one page. I found one, only one, that would do for either motor, but > he only had one. Std e-core. If he had 2 of them, I'd have bought > them. $40. And one for $15 that could have been cobbled up but it was > on your side of the pond so the shipping would have made it north of a > $50 bill. MPJA, would have needed too many to get the amps and volts. > I have some toroids I'd have to hook up and see what they are, but I > doubt the wattage is there. I might investigate that tommorrow. > > Thanks Andy. > > Cheers, Gene Heskett
I have now managed to procure, or excavate from my boneyard, some toriods that should have enough iron to run the motors, developing about 63.5 volts for the nema 34 Z motor, and about 45 volts for the X motor when both are loaded up at reduced current because its not moving. Except I now have about 2.75 volts of noise at what looks like around 335KHz. I at first tied the line cordage's green wire to a bolt at the top of the removable plate the power stuff is built on, then disconnected it which made very very little difference. So I ran a hunk of 5/16" wide braid about a foot long from the green wire to the bolt I had installed in the bottom of the box, intending to have a star ground. Very slight change in the ringing frequency as the noise pulse dies away. I can't think of a thing in that whole kit that would be switching at 335 KHz. Except the regulator in the pi's power input. I also note that the pi's grounded to hdpe sheet metal has about 20% more of this noise on the load side of its power cables ferrite choke than on the psu. The - screw on these 2 psu's has never been connected to this "star" ground bolt, so I guess I'll move the supply to where thats not a 16" inch run, ground both the ground terminal and the - screw to this bolt & run a twisted pair over to the pi & 7i90. The 2 new supplies aren't grounded at their power input terminals, but the motor cables are well shielded and the shields only grounded at this same bolt. Not grounded, cut off short at the motors. Needless to say, it will not run lcnc as the noise is creating joint errors so fast I can reset it, and they are both tripped off before I can get a finger on one of the arrow keys. Likewise the encoders velocity output is totally spastic w/o moving the spindle. I have some ideas to check tomorrow, like disconnect both motor supplies just for S&G so I can get an idea if its motor driver noise. Those brick wall corcom line filters I ordered haven't appeared yet. Nor have the ti isolator samples. Garbage out night, I have to go play housekeeper. ) Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
