G8MNY TECH 23.08.19 06:13l 134 Lines 6178 Bytes #365 (0) @ WW
BID : 18579_GB7CIP
Subj: AC 3 Phase Power
Path: OK0NBR IR2UBX DB0RES WA7V VK7AX VK6HGR GB7CIP
Sent: 190823/0907Z @:GB7CIP.#32.GBR.EURO #:18579 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW

By G8MNY (Updated Aug 08)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
3 PHASE POWER
This is how AC power is normally generated & distributed, it is more efficient than other AC systems, except for DC that is the most efficient, but that is difficult & costly to transform the voltage at high power.

The wire colour scheme may differ between countries & also the voltage!

The phase angle between phases is 120°, because of this the voltages are added up vectorialy, so at first sight 2x 230V does not make 415V between 2 lives. You divide by √3 (1.732) to get the line to neutral voltage.

Line
BROWN ───────────────── STAR LOADS DELTA LOADS
(red) /│\ /│\ /│\ o Brown
415V | | Brown o
\│/ 415V | Load / \
BLACK ───────────── | │ / 60° \
(yellow) /│\ | /│\ | 120° o 120° 414V 415V
415V | | | / \ Load Load
\│/ \│/ | | Grey 120° Black / 60° 60° \
GREY ───────── | | Load Load o______ 415V ______o (blue) /│\ | | o o Grey Load Black
230V 230V 230V If loads balanced No Neutral
\│/ \│/ \│/ centre = neutral &
BLUE ───────────────── loads all get 230V
(black) (neutral)

The 3 line currents are normaly loaded up to be as equal as possable to reduce the current in the neutral cable normal the same gauge. But Philip M1EUR reports that Neutal cable may need to be 2x the gauge (CSA) if electronic loads with very high harmonic current are used!


NEW COLOUR HAZARDS !
New EU colours are Brown Black Grey for Lives & Blue Neutral
replacing Red Yellow Blue for Lives & Black Neutral. Green/Yel earth.

N.B. the lethal change for both BLACK & BLUE colours!

Also note the colour layout of new 3 phase 4 core cable means, that a joint can not be straight to an old cable & bigger joints casings will be needed to allow for at least 2 cores to be bridged!

Single phase will change from Red live, Black Neutral to Brown & Blue respectifully. But highly confusing in a 3 phase board with both old black
wire loads for Neutrals & Black Bus feed for live! Brown & Blue sleeves are to be used over Red & Black wires!


3 PHASE TRANSFORMERS
Like any transformer the voltage can be changed, or isolated etc. The difference being that 3 legs of the transformer carry the windings rather than just the middle. ┌───────────┐ The winding connections can be either STAR or
│ ┌──┐ ┌──┐ │ DELTA or combinations of both.
┌┴─┴┐┌┴─┴┐┌┴─┴┐ When cross connected star-delta a rotation of
Windings- │ 1 ││ 2 ││ 3 │ 90° in phase occurs. (30° to other phases)
└┬─┬┘└┬─┬┘└┬─┬┘ .
Laminated │ └──┘ └──┘ │ | or / \ becomes _ / or /'│
Core - └───────────┘ / \ '---' \ '\,│

(due to magneto striction of the core, audio hum given off from the steel is @ 300Hz on 50Hz system)


3 PHASE RECTIFICATION
With rectification 3 diodes gives about 30% ripple at 150Hz (3x supply) the ripple is not much as singe phase, as some of the 120° voltages overlap.
___________________
_│_ _│_ _│_ /|\
/_\ /_\ /_\ | 100% ┤ _.-._ _.-._ _.-._ ┬ Ripple
Br ───┘ │ │ Raw 70%_│ / \ / \ / │
│ │ DC │ │ │ │ ~
Bk ─────────┘ │ | │ │ │ │ │ │
│ | ││ │ │ │ │
Gy────────────────┘ | ┼────────┬───┬───┬───┬───┬─ Phase Angle
\|/ 0° 120 180 240 310 360° Bl────────────────────────


3 PHASE BRIDGE RECTIFIERS
Only 6 diodes produce a 3 phase bridge & that gives about 14% @ 300Hz (6x supply) ripple peak to peak, as more of the 60° voltages overlap.
________________
_│_ _│_ _│_ /|\
/_\ /_\ /_\ | 100% ┤ _.-._.-._.-._.-._.-._ ┬ Ripple
Br ───┤ │ │ | 86% /│ / / \ / \ / \ / \ / ~
│ │ │ | │ │ │ │ │ │ │
Bk ───)─────┤ │ Raw │ │ │ │ │ │ │ │ │ │ │
│ │ │ DC ││ │ │ │ │ │ │
Gr ───)─────)─────┤ | ┼────┬───┬───┬───┬───┬───┬─ Phase Angle
_│_ _│_ _│_ | 0° 60 120 180 240 310 360°
/_\ /_\ /_\ \|/
└─────┴─────┴────


12 PHASE RECTIFIERS
With push pull or 3 phase bridge system, & using both star & delta windings there can effectively be 12 lives that are only 30° apart. This can also be achieved with push pull phase on each leg of the transforner.

| \ / \ | /
* + * = *
/ \ | / | \

Using 2x 3 phase bridges or 12 winding & diodes the resultant ripple is only about 3.6% @ 600Hz, assuming all the voltages are equal! Very little filtering is then needed for say a 100kW Tx HT supply.
________________________
_│_ _│_ _│_ _│_ _│_ _│_ /|\
Floating /_\ /_\ /_\ /_\ /_\ /_\ |
. BrD──┤ │ │ │ │ │ | 100% ┤ _.-.-.-.-.-.-.-.-. = Ripple
/ \ BkD──)───┤ │ │ │ │ | 96% /│ / / /\/\/\/\/\/\/\
'---' GyD──)───)───┤ │ │ │ | │ │ │ │ │ │ │ │ │ │ │
Windings │ │ │ │ │ │ Raw │ │ │ │ │ │ │ │ │ │ │ │
BrS──)───)───)───┤ │ │ DC ││ │ │ │ │ │ │ │ │ │ │
| BkS──)───)───)───)───┤ │ | ├──┬─┬───┬───┬───┬───┬─ Phase Angle
/ \ GyS──)───)───)───)───)───┤ | 0° 30 60 120 180 240 310°
_│_ _│_ _│_ _│_ _│_ _│_ |
/_\ /_\ /_\ /_\ /_\ /_\ \|/
└───┴───┴───┴───┴───┴────


See my Tech bul "AC Theory".


Why Don't U send an interesting bul?

--- Mystic BBS v1.12 A43 (Linux/32)
* Origin: HAMRADIO telnet slacko.kozow.com (21:5/101)

G8MNY TECH 23.08.19 06:13l 134 Lines 6178 Bytes #365 (0) @ WW
BID : 18579_GB7CIP
Read: GUEST
Subj: AC 3 Phase Power
Path: OK0NBR IR2UBX DB0RES WA7V VK7AX VK6HGR GB7CIP
Sent: 190823/0907Z @:GB7CIP.#32.GBR.EURO #:18579 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW

By G8MNY (Updated Aug 08)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
3 PHASE POWER
This is how AC power is normally generated & distributed, it is more efficient than other AC systems, except for DC that is the most efficient, but that is difficult & costly to transform the voltage at high power.

The wire colour scheme may differ between countries & also the voltage!

The phase angle between phases is 120°, because of this the voltages are added up vectorialy, so at first sight 2x 230V does not make 415V between 2 lives. You divide by √3 (1.732) to get the line to neutral voltage.

Line
BROWN ───────────────── STAR LOADS DELTA LOADS
(red) /│\ /│\ /│\ o Brown
415V | | Brown o
\│/ 415V | Load / \
BLACK ───────────── | │ / 60° \
(yellow) /│\ | /│\ | 120° o 120° 414V 415V
415V | | | / \ Load Load
\│/ \│/ | | Grey 120° Black / 60° 60° \
GREY ───────── | | Load Load o______ 415V ______o (blue) /│\ | | o o Grey Load Black
230V 230V 230V If loads balanced No Neutral
\│/ \│/ \│/ centre = neutral &
BLUE ───────────────── loads all get 230V
(black) (neutral)

The 3 line currents are normaly loaded up to be as equal as possable to reduce the current in the neutral cable normal the same gauge. But Philip M1EUR reports that Neutal cable may need to be 2x the gauge (CSA) if electronic loads with very high harmonic current are used!


NEW COLOUR HAZARDS !
New EU colours are Brown Black Grey for Lives & Blue Neutral
replacing Red Yellow Blue for Lives & Black Neutral. Green/Yel earth.

N.B. the lethal change for both BLACK & BLUE colours!

Also note the colour layout of new 3 phase 4 core cable means, that a joint can not be straight to an old cable & bigger joints casings will be needed to allow for at least 2 cores to be bridged!

Single phase will change from Red live, Black Neutral to Brown & Blue respectifully. But highly confusing in a 3 phase board with both old black
wire loads for Neutrals & Black Bus feed for live! Brown & Blue sleeves are to be used over Red & Black wires!


3 PHASE TRANSFORMERS
Like any transformer the voltage can be changed, or isolated etc. The difference being that 3 legs of the transformer carry the windings rather than just the middle. ┌───────────┐ The winding connections can be either STAR or
│ ┌──┐ ┌──┐ │ DELTA or combinations of both.
┌┴─┴┐┌┴─┴┐┌┴─┴┐ When cross connected star-delta a rotation of
Windings- │ 1 ││ 2 ││ 3 │ 90° in phase occurs. (30° to other phases)
└┬─┬┘└┬─┬┘└┬─┬┘ .
Laminated │ └──┘ └──┘ │ | or / \ becomes _ / or /'│
Core - └───────────┘ / \ '---' \ '\,│

(due to magneto striction of the core, audio hum given off from the steel is @ 300Hz on 50Hz system)


3 PHASE RECTIFICATION
With rectification 3 diodes gives about 30% ripple at 150Hz (3x supply) the ripple is not much as singe phase, as some of the 120° voltages overlap.
___________________
_│_ _│_ _│_ /|\
/_\ /_\ /_\ | 100% ┤ _.-._ _.-._ _.-._ ┬ Ripple
Br ───┘ │ │ Raw 70%_│ / \ / \ / │
│ │ DC │ │ │ │ ~
Bk ─────────┘ │ | │ │ │ │ │ │
│ | ││ │ │ │ │
Gy────────────────┘ | ┼────────┬───┬───┬───┬───┬─ Phase Angle
\|/ 0° 120 180 240 310 360° Bl────────────────────────


3 PHASE BRIDGE RECTIFIERS
Only 6 diodes produce a 3 phase bridge & that gives about 14% @ 300Hz (6x supply) ripple peak to peak, as more of the 60° voltages overlap.
________________
_│_ _│_ _│_ /|\
/_\ /_\ /_\ | 100% ┤ _.-._.-._.-._.-._.-._ ┬ Ripple
Br ───┤ │ │ | 86% /│ / / \ / \ / \ / \ / ~
│ │ │ | │ │ │ │ │ │ │
Bk ───)─────┤ │ Raw │ │ │ │ │ │ │ │ │ │ │
│ │ │ DC ││ │ │ │ │ │ │
Gr ───)─────)─────┤ | ┼────┬───┬───┬───┬───┬───┬─ Phase Angle
_│_ _│_ _│_ | 0° 60 120 180 240 310 360°
/_\ /_\ /_\ \|/
└─────┴─────┴────


12 PHASE RECTIFIERS
With push pull or 3 phase bridge system, & using both star & delta windings there can effectively be 12 lives that are only 30° apart. This can also be achieved with push pull phase on each leg of the transforner.

| \ / \ | /
* + * = *
/ \ | / | \

Using 2x 3 phase bridges or 12 winding & diodes the resultant ripple is only about 3.6% @ 600Hz, assuming all the voltages are equal! Very little filtering is then needed for say a 100kW Tx HT supply.
________________________
_│_ _│_ _│_ _│_ _│_ _│_ /|\
Floating /_\ /_\ /_\ /_\ /_\ /_\ |
. BrD──┤ │ │ │ │ │ | 100% ┤ _.-.-.-.-.-.-.-.-. = Ripple
/ \ BkD──)───┤ │ │ │ │ | 96% /│ / / /\/\/\/\/\/\/\
'---' GyD──)───)───┤ │ │ │ | │ │ │ │ │ │ │ │ │ │ │
Windings │ │ │ │ │ │ Raw │ │ │ │ │ │ │ │ │ │ │ │
BrS──)───)───)───┤ │ │ DC ││ │ │ │ │ │ │ │ │ │ │
| BkS──)───)───)───)───┤ │ | ├──┬─┬───┬───┬───┬───┬─ Phase Angle
/ \ GyS──)───)───)───)───)───┤ | 0° 30 60 120 180 240 310°
_│_ _│_ _│_ _│_ _│_ _│_ |
/_\ /_\ /_\ /_\ /_\ /_\ \|/
└───┴───┴───┴───┴───┴────


See my Tech bul "AC Theory".


Why Don't U send an interesting bul?

--- Mystic BBS v1.12 A43 (Linux/32)
* Origin: HAMRADIO telnet slacko.kozow.com (21:5/101)