Before you start looking that up, common mode refers from line or neutral to ground and "differential" or transverse or normal mode refers to noise between line and neutral. Common mode is the big culprit.
A shielded transformer is also a capacitive/reactive inductive load, which filter frequencies beyond 50/60 Hz. I've seen examples (not confirmed) of up to 8:1 spike reduction through transformers as well. What they don't do is regulation, except for motorized autoformers but usually too slowly for our intent. They also don't prevent ground loops because, by code, ground has to be continous.
Chose an industrial step-down transformer because
1) EI cores are not as close coupled as toroids
2) to get balanced AC out of either 120V or 240V
3) Picked up a used one for near pocket change
4) designed for demanding loads, not packaging
5) very high current requirement (5KVA/20A balanced)
A shielded transformer is also a capacitive/reactive inductive load, which filter frequencies beyond 50/60 Hz. I've seen examples (not confirmed) of up to 8:1 spike reduction through transformers as well. What they don't do is regulation, except for motorized autoformers but usually too slowly for our intent. They also don't prevent ground loops because, by code, ground has to be continous.
Chose an industrial step-down transformer because
1) EI cores are not as close coupled as toroids
2) to get balanced AC out of either 120V or 240V
3) Picked up a used one for near pocket change
4) designed for demanding loads, not packaging
5) very high current requirement (5KVA/20A balanced)