- Joined Jul 18, 2013
Good points. I don't automatically Earth (solid connection to the Earth grounded equipment frame) all AC/DC isolated power supplies on high power industrial equipment automation control systems because it can be dirty and inject noise into sensitive circuits signal common. You need to use supplies with very low AC supply leakage (no Y cap) to the DC terminals for critical floating (utility potentials) power applications.
That's what I do for motor control signals but lots of other things live in a world of floating potentials where things like Triaxial cable is needed. Signal, signal shield/ active guard and 'ground'.My philosophy when wiring control cabinets has been to set up a star GND spot using a copper bus, and take the service earth conductor, & all PS commons, shields etc.
Also adopting most of the what the Siemens paper on equi-potential bonding suggest (prevent ground loops). Also with that in effect, ground both ends of shielded cables.
So far it has served me in good stead.
https://forum.allaboutcircuits.com/threads/ctmu-clarifications.115248/post-899468Another application for triaxial cables is for probes taking precision low-current measurements where the leakage current through the insulator between the core and shield would normally alter the measurements. The core (known as the force) and the inner shield (known as the guard) are kept at approximately the same electrical potential by a voltage buffer/follower, thus the leakage current between them is zero for all practical purposes, despite the imperfections of the insulation. Instead, the leakage current occurs between the inner and outer shields, which does not matter since that current will be supplied by the buffer circuit rather than the device under test and will not affect measurements. This technique can provide almost perfect elimination of leakage current but becomes less effective at very high frequencies as the buffer cannot follow the measured voltage accurately.
|Thread starter||Similar threads||Forum||Replies||Date|
|Interesting- SiC JFETs as next gen switching devices||Power Electronics||8|
|The world's most interesting tool||General Science, Physics & Math||2|
|Interesting article gives whole new meaning to "Electronic Warfare"||General Electronics Chat||32|
|Interesting and timely article given recent events on college campuses.||Off-Topic||132|
|S||Interesting Article on General Relativity||General Science, Physics & Math||19|
by Aaron Carman
by Robert Keim
by Dale Wilson
by Robert Keim