Circuits on phases

[Cj24]

Hi I was wondering if anyone could explain about circuits on phases, on sites that I work on we r given drawings with lighting circuits and power circuits and I get told we need to keep certain circuits on certain phases but dnt knw why, obv you have exp L1 L2 and L3

 

[wallyanker]

possibly to balance the loads evenly across the 3 phases

 

[Hawk81]

possibly to balance loads and could also be to prevent there being 400v between 2 different socket outlets or 400v at 1 light switch etc.

 

[Cj24]

So basically you want roughly the same amount of load coming off each phase

 

[Notsosmart]

As far as is reasonably practicable* Yes. The main reason for this is to reduce power factor thus keeping costs down, also unbalanced loads will likely shove any extra energy down the neutral thus possibly getting higher currents than the neutral conductor is rated for.

(* Get used to this term, it is loose legal jargon.)

 

[pmac10]

As far as is reasonably practicable* Yes. The main reason for this is to reduce power factor thus keeping costs down, also unbalanced loads will likely shove any extra energy down the neutral thus possibly getting higher currents than the neutral conductor is rated for.

(* Get used to this term, it is loose legal jargon.)

i would want to increase power factor as energy companies penalise you for wastage down the neutral.

 

[Notsosmart]

Ok I meant to say 'improve' power factor to as close to unity as possible.

 

[pmac10]

thats what i thought you meant m8, aim for 1.0

 

[Golden_Boy]

Ok I meant to say 'improve' power factor to as close to unity as possible.

I was just about to ask about that. When I went to college a bad power factor REDUCED the bill?
Thats why factories with loads of big motors in it had a HUGE capacitor strapped accross the mains supply. can't have something for nothing

 

[Notsosmart]

A 'bad' power factor (either leading or lagging) will increase the bill, so if you have highly resistive loads(impedance) expressed as a decimal i.e.0.7~ then large capacitors (usually) are then used to push the power factor closer to Unity ~ 1.

I will try to dig out a useful data sheet on the subject. (for anyone interested)

Edit: Found it.