Timmyp said:
Hey everyone,
The first of what may seem like a lot of simple questions to some of you!!
Could you explain to me what 3-phase electricity is in relation to a standard electrical supply?
Your help is much appreciated
Timmy P
Hi Timmy - The standard
power outlet that you have on the wall is a single
phase 240V
outlet. There is an active (hot) cable that sends 240V to the application plugged in and a
neutral cable that returns the
voltage. There is also an earth (
ground)
connector that is there to reduce your risk of electrocution should things go bad.
Three
phase has 3 Active connectors and one
neutral and one earth, although, some applications do not use a
neutral but for
theatre applications in the UK and Australia, you will need the
neutral.
Each active
phase is 120' out of
phase to the next one which is why an
electric motor can run from just the three actives and without a
neutral, as one is at +240 one at -240 and one at 0 at any one
point in the cycle. But for
power, you need the
neutral. When you see a three
phase distro, this effectively takes three
phase and splits it into several single
phase outlets. Commonly, 3 to 4 10A single
phase outlets will be branched off of each 32A three
phase Active. Thus, you will see
distro units with 9 or 12 single
phase sockets on them and most will be marked as
phase 1,
phase 2 and
phase 3. Often they will be marked with colour (ie, red 1 or white 3) or with numbers (ie, 1-1 or 2-3).
Three
phase generally carries more
current and is used in lighting and sound because you can
power up more applications. For example, a common 3phase
dimmer will have 12x10A circuits on it where a common 4pac
dimmer will only have a total capacity of 10A.
That is a fairly basic explanation but I don’t want to go into more in depth discussion at this
point until I know if you have any other questions. There is a lot more to know when it comes to distribution of three
phase power but I don’t want to get to detailed at this
point, without knowing your specific questions (if any).
Hope this was some help.