Drew
18-01-2013, 07:45 AM
I live in Australia where we have 3 phase 420volts and single phase 240volts.
On the Refrigeration systems I work on ( single phase 240v) if I take a reading with my ammeter on the live I get say 10 amps ,I will also get 10amps on the return neutral.
Electricians I speak to say that a neutral should not carry current unless the loads are unbalanced. This confuses me?
Are we referring to two different style neutrals , one being the single phase return to the main neutral, and the other is the main neutral. Does the main neutral not carry current if the 3 phases are balanced and then somehow cancel each other out.
Therefore if we have three resistive loads,all the same resistance ,each fed by a phase and say each draws 10amps. This 10 amps would be seen on each individual return neutral , but as soon as they join together on the common neutral bar the main neutral going on further would read 0volts as they have balanced out?
On the Refrigeration systems I work on ( single phase 240v) if I take a reading with my ammeter on the live I get say 10 amps ,I will also get 10amps on the return neutral.
Electricians I speak to say that a neutral should not carry current unless the loads are unbalanced. This confuses me?
Are we referring to two different style neutrals , one being the single phase return to the main neutral, and the other is the main neutral. Does the main neutral not carry current if the 3 phases are balanced and then somehow cancel each other out.
Therefore if we have three resistive loads,all the same resistance ,each fed by a phase and say each draws 10amps. This 10 amps would be seen on each individual return neutral , but as soon as they join together on the common neutral bar the main neutral going on further would read 0volts as they have balanced out?