Teach me - Floodlights!

[sellers]

ok, so been doing a job re-lamping, replacing damaged ballasts and ignitors on a local floodlit sports centre. The jobs fine replacing like for like except winching down the towers is starting to get to my back.

Anyway I just wondered if anyone could explain the setup within these lamp-posts as I did ask quite an experienced guy at work and he hadn't seen it before either.

Take one lamppost with 6 x 2000w SON HQI-T floodlights on.

The incoming is 4 3phase swa's. No neutrals. Each one to an 3 phase isolator (4 again). This then splits up into 6x2 phase 45a MCB's. (Never really seen a 2 phase mcb)

Out of these the 2 phases then go throught the ballast, ignitior (with a capacitor tapped off it) then upto the light.

My questions are, how do you have 2 phases on a lamp. No neutrals, etc. Just after a bit of indepth information really.

O)

 

[sellers]

Sorry I dont think they're sons, more metal halide. Allthough Im not 100% clued up on lamp types.

 

[Andy™]

they may be 400v.

MH: white

SON: golden tint

 

[oldtimespark]

Hi have a look at this link of a pdf data sheet here some of the units are for 415 v operation.

 

[a1]

And any Two (2) Phases = 400 V, as you know, Sir.

 

[Andy™]

And any Two (2) Phases = 400 V, as you know, Sir.

just hope its not split phase

 

[sellers]

Just struggling to comprehend how a lamp can take 2 phases. They must be balanced to have no neutral, right?

these are the lamps

 

[Andy™]

Just struggling to comprehend how a lamp can take 2 phases. They must be balanced to have no neutral, right?these are the lamps

your connecting between 2 phases, no neutral is needed. think of how a delta transformer is wired - each of the coils in there can be replaced with a ballast. they do not need to be balanced

and that lamp looks like SON

 

[elvis]

they do not need to be balanced

It's the old potential difference... they need to be out of ballance (on different phases) to make a circuit.