What does Ground (GND) mean?

[ZeusMC]

Ok, thanks for the interesting input guys,

 

[KeepItSimpleStupid]

here is some other useful information (vaguely related to ground)
1. Twisting reduces EMI
2. Shielding reduces RFI. You should connect the shield at only one end. The preferred end is the signal source end.

"Likes" are appreciated. (Right bottom of a post)

 

[MaxHeadRoom78]

Actually there is a paper out by Siemens, that covers equi-potential bonding when wiring industrial panels, and they claim that under these conditions, shielded cable can now be grounded both ends, due to the process eliminating ground loops.
Max.

 

[ZeusMC]

here is some other useful information (vaguely related to ground)
1. Twisting reduces EMI
2. Shielding reduces RFI. You should connect the shield at only one end. The preferred end is the signal source end.

"Likes" are appreciated. (Right bottom of a post)

"Likes" are appreciated. (Right bottom of a post) OK, sure.

 

[Externet]

I know electric eels love it!
They become Re-Charged!

Well, that would be underH2O, not underGND... What about the non-electric fish ? They may not like it !

 

[throbscottle]

I was reading about shielding last year. The advice was to always connect the shield at both ends of the cable unless doing so will create problems (like, if the ground potentials at each end of the cable are different, or if it will create a ground loop). Very educational piece, might have been one of the AD articles.

Ok I'm confused. Since RFI is a form of EMI, don't twisting and shielding achieve the same thing?

 

[MaxHeadRoom78]

I was reading about shielding last year. The advice was to always connect the shield at both ends of the cable unless doing so will create problems (like, if the ground potentials at each end of the cable are different, or if it will create a ground loop). Very educational piece, might have been one of the AD articles.

Ok I'm confused. Since RFI is a form of EMI, don't twisting and shielding achieve the same thing?

As per the Siemens paper quoted, the practice of equi-potential bonding of the metalic parts of a system or installation is done in an effort to eliminate ground loops. When this is done, shielding can be grounded at both ends may be carried out.
Twisting of current carrying cables reduces or eliminates EMI.
Max.

 

[KeepItSimpleStupid]

k I'm confused. Since RFI is a form of EMI, don't twisting and shielding achieve the same thing?

One is radio frequency RFI and the other EMI magnetic e.g 60 Hz.

You do have twisted pair shielded cable.

The shield provides a Faraday (https://en.wikipedia.org/wiki/Faraday_cage) cage around the conductors.

Twisting, is generally used with differential transmitters and receivers. So, suppose a cable is runnimg parallel to a power line. voltage would be induced in both conductors , but in opposite directions, so they tend to cancel.

 

[MaxHeadRoom78]

Twisting also carried out on such as servo motor power (PWM) conductors etc, where encoder is also ran close by.
Or 3ph out of VFD's etc, where the 3 conductors contain high frequencies.
Max.