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G8MNY > TECH 22.04.13 21:21l 86 Lines 3764 Bytes #999 (0) @ WW
BID : 19270_GB7CIP
Read: GUEST
Subj: Essential Mains Changeover
Path: IZ3LSV<F1OYP<ON0AR<GB7CIP
Sent: 130422/1654Z @:GB7CIP.#32.GBR.EU #:19270 [Caterham Surrey GBR] $:19270_GB
From: G8MNY@GB7CIP.#32.GBR.EU
To : TECH@WW
By G8MNY (Updated Dec 12)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
I designed this simple unit to bypass 230V mains problems at a local community
radio station, that needs essential mains for 24/7 computers. The building's
Mains Consumer Unit had been updated with two Earth leakage Residule Current
Devices, feeding two Main Contact Breakers banks, but also with a separate
"Alternate Mon RCD feed" provided just to the UPS system.
SCHEMATIC
NORMAL Bypass UPS Bypass
RELAY RELAY
Normal ÚÄÄÄÄÄÄÄ¿ ÚÄÄÄÄÄÄ¿
RCD feed >ÄÄÅÄo ³ ÚÄÄÄÄÄÄÅÄo ³
³ \ ³ ³ ³ \ ³
Alternate >ÄÄÅÄo \ÄÄÄÅÄÄÄ´ ÚÄÄÄÄÅÄo \ÄÄÅÄÄÄ>Essential
Non RCD ÀÄÄÄÂÄÄÄÙ ³ ³ ÀÄÄÄÂÄÄÙ Power Feed
Bypass ÚÁÄÁ¿ Bypass
³UPS³
ÀÄÂÄÙ
36V
Battery
CIRCUIT
For maxamium flexibility, the source load plugs & sockets, are the Standard UK
13A fused type on this mains source box. But the distrubution is on racked kit
seperately fused EIC banks.
Alternate Normal
Non RCD RCD
EÄÄÄÄÄÄÄÄÄEÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄE
Mains Mains ³ Essential
Plug Plug ³ Sockets
N L N L NORMAL ³ UPS 250V~ N L
³ ³ ³ ³ ÚÄÄÄ¿ ³ ÚÄÄÄ¿ 470n ³ ³
³ ³ ÃÄÄÄÄ)ÄÄ´30KÃÄ¿ ³ Ú´30KÃÄ´ÃÄÄ¿ ³ ³
³ ³ ³ ³ ÀÄÄÄÙ ³ ³ ³ÀÄÄÄÙ 15K ³ ³
Ãneon´ Ãneon´ Use 15K ³ ³ Use ³ Ãneon´
³ ³ ³ ÃÄÄÄ\ÄÄÄÄÙ ³ ÀÄÂneonÂÄ\ÄÙ ³ ³
³ ³ ³ o ³ ³ ÃÄÄÄo ³ ³
³ ÀÄÄÄÄ)ÄÄÄÄo\ÄÄÄÄÄÄÂÄÄÄÄÄ)ÄÄÄÄÄ)ÄÄÄÄ)ÄÄÄo\ÄÄÄÄ)ÄÄÄÄÙ
³ ³ NORMAL ³ ³ ³ ³ UPS ³
³ ÀÄÄÄÄo ³ ³ ÃÄÄÄÄ)ÄÄÄo ³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄo\ÄÄÄÂÄÄ)ÄÄÄÄÄ)ÄÄÄÄÄ)ÄÄÄÄ)ÄÄÄo\ÄÄÄÄÙ
³ ³ ÚÄÄÁÄÄ¿ ³ ³
N³in³L ³E E³ N³out ³L IEC
ÚÁÄÄÁÄÄÁÄÄÄÄÄÁÄÄÁÄÄÄÄÁ¿Connectors
³ 1kW 36V 100% UPS ³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
The four neons indicate power status, & the two switches enable safe manual
override of the relays for Normal Mains circuit & UPS servicing etc.
I found good quality 3x 15A changeover AC relays with 30Kê coils, but they
would stay operated down to 140V! So added series 15k 1W resistor to get a
better operate to failure voltages of 205 to 190V.
However on flattening UPS the battery, I discovered the UPS can put out DC,
blowing kit fuses (SMPSUs PCs OK, Transformer kit not!) So I add a series 250V
AC Cap to the UPS bypass relay to ensure the UPS gets bypassed if it does a
mains wobbly again!
WARNING
Bypassing RCDs is not to be taken lightly! The station need for 24/7 essential
power is considered very important. Normal building mains is all RCD protected,
only the specialised kit on IEC distribution panels have the bypass capability.
And it can be easily be configured back to RCD only, for safer live mains while
wiring work is going on etc. you just unplugging the non RCD supply, put in an
a temporay RCD adaptor. (Most Adaptors DO NOT STAY ON on a mains fail!)
See my Tech buls on:- "APC Smart 900 UPS", "DURITC 1kW 230V Inverter/UPS",
"META HF Millennium 810H UPS", "Constant Voltage Transformers", "Variacs",
"70-260V Mains Auto Transformer", "Maplin Mains Meter 2000MU-UK",
"Mains Power Protection", "Mains Peak/RMS/Mean Meter", "Voltage Dependent
Resistors", & "Portable Appliance Testing"
Why don't U send an interesting bul?
73 De John, G8MNY @ GB7CIP
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