All About Circuits Forum  

Go Back   All About Circuits Forum > Electronics Forums > General Electronics Chat

Notices

General Electronics Chat Discussion forum for general chat about anything electronics related, including asking questions about material in the All About Circuits E-book, Worksheets, and Videos.

Reply   Post New Thread
 
Thread Tools Display Modes
  #1  
Old 12-08-2008, 06:37 AM
mmodi mmodi is offline
New Member
 
Join Date: Dec 2008
Posts: 2
Default Wiring of Inverter/Home UPS

Hi,

I am using a 800VA (12V) Home UPS System as Inverter/UPS for PC. I need some technical assistance regarding wiring.

Please let me know:

- What is the difference between the attched wiring diagrams?

As I requested to my electrician for wiring as per the diagram a for whole house, but he says that it is impractical for the inverter wiring (however, he can do the same for my PC only, and for other appliances like light & fans he adopted b method).

Kindly suggest.

Thanks with regards,

M Modi
Attached Images
File Type: jpg wiring.JPG (29.8 KB, 1259 views)
Reply With Quote
  #2  
Old 12-08-2008, 03:10 PM
SgtWookie's Avatar
SgtWookie SgtWookie is offline
Expert Member
 
Join Date: Jul 2007
Location: In the vast midwest of the USA; CST
Posts: 21,989
Default

Diagram a) is correct.
Diagram b) is not correct, as there is no return path to the inverter. The inverter should automatically take care of switching between the mains and it's own output.

If your mains voltage is 120, your inverter will only supply 6.67A output maximum. That is not much power. If it is being run from 12.6v batteries, the drain on them will be about 75 Amperes while the inverter is supplying the 6.67A output. Unless you have a very large bank of batteries, you will have power for only a short period of time.
__________________
General info:
If you have a question, please start a thread/topic. I do not provide gratis assistance via PM nor E-mail, as that would violate the intent of this Board, which is sharing knowledge ... and deprives you of other knowledgeable input.
Reply With Quote
  #3  
Old 12-09-2008, 02:25 AM
mmodi mmodi is offline
New Member
 
Join Date: Dec 2008
Posts: 2
Default

Thanks for the reply, I am from India and here the supply Voltage is 220. I know that the Diagram A is ideal, but here mostly Diagram B is in practice (and its working - it may be that inside inverter the mains' neutral is connected to the output neutral of inverter, is it possiable?). This is a Home UPS system with a 135 AH power bank.
Reply With Quote
  #4  
Old 12-09-2008, 05:06 AM
SgtWookie's Avatar
SgtWookie SgtWookie is offline
Expert Member
 
Join Date: Jul 2007
Location: In the vast midwest of the USA; CST
Posts: 21,989
Default

Since your mains are 220, you'll only get 3.63A from your inverter; your battery draw will still be around 75A. At the very most you will get 1.8 hours of operation at full load, but to maximize your battery life, you should not let it operate for more than about 1/2 hour (full load) on the batteries. Longer than that, and your batteries will become heavily discharged, which is not good for them.
__________________
General info:
If you have a question, please start a thread/topic. I do not provide gratis assistance via PM nor E-mail, as that would violate the intent of this Board, which is sharing knowledge ... and deprives you of other knowledgeable input.
Reply With Quote
  #5  
Old 12-09-2008, 07:27 AM
leftyretro's Avatar
leftyretro leftyretro is offline
Senior Member
 
Join Date: Nov 2008
Location: Hercules, Ca. (SF Bay Area)
Posts: 394
Default

Here is the USA your circuit example B would not be compliant with electrical safety standards and would be in violation with local and national building codes. The neutral wire in circuit B example would have to carry current back to the panel for both loads.

It is most likely the same wire size as the single line terminal wire and therefore is in danger of being undersized for the current draw of both loads even if both line wires are protected with a properly sized circuit breaker for the line wire size.

I would assume that you must use single wire runs in your typical home to even be able to consider wire circuits as shown in your example B. Here we always use 3 conductor cable (line, neutral, ground) and daisy chain to loads and each cable run would typically wire to a 20 or 30 amp circuit beaker. There may be a 6 to 12 such runs in a typical home here.

Lefty
__________________
Measurement changes behaviour
Reply With Quote
  #6  
Old 03-04-2009, 04:53 PM
AnandMisal AnandMisal is offline
New Member
 
Join Date: Mar 2009
Posts: 1
Default Inverter Wiring Issue

Hi
I am from India and planning to use UPS / Inverter System at my home.
What will happen if I connect ( Diag 2 ) HOME UPS Neutral (N) to LOAD ON UPS Neutral and Mains Neutral BOTH. Will that solve my problem of return path OR is it going to create any major issues?

Regards
Anand
Reply With Quote
  #7  
Old 03-04-2009, 05:12 PM
b.shahvir's Avatar
b.shahvir b.shahvir is offline
Senior Member
 
Join Date: Jan 2009
Location: Mumbai (Bombay), India.
Posts: 441
Default

But wat's the logic behind sharing a common neutral as depicted in fig. (b) ? External neutral means you are atttempting to by-pass the inherent safety equipment of the UPS. This can result in safety issues!
Reply With Quote
  #8  
Old 05-20-2009, 10:54 AM
KASIM999 KASIM999 is offline
New Member
 
Join Date: May 2009
Posts: 1
Default

Iwant to get wiring digrams fof MAXIMA inverter if possible
Reply With Quote
  #9  
Old 07-12-2009, 10:07 AM
agnii agnii is offline
New Member
 
Join Date: Jul 2009
Posts: 1
Default Wanted to know how youfinally wired

Were you able to follow digram a), if yes what wiring changes it involved.
Reply With Quote
  #10  
Old 10-16-2009, 02:44 PM
rajudp rajudp is offline
New Member
 
Join Date: Nov 2008
Posts: 1
Default

i think both a and b are correct. In offline ups the neutral is common for both mains and ups out. But for online primary neutral is isolated with ups out neutral
Reply With Quote
Reply   Post New Thread

Tags
, ,


Related Site Pages
Section Title
Worksheet Latch circuits
Worksheet Electromechanical relay logic
Worksheet Power conversion circuits
Worksheet Class A BJT amplifiers
Worksheet Bipolar junction transistors in active mode
Textbook Harmonics in polyphase power systems : Polyphase Ac Circuits
Textbook Three-phase power systems : Polyphase Ac Circuits
Textbook Single-phase power systems : Polyphase Ac Circuits
Worksheet Voltage divider circuits
Textbook "Ladder" diagrams : Ladder Logic


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to design an Uninterruptible Power Supply (UPS)? mdzhdhaka The Projects Forum 9 10-22-2008 02:01 AM
how to remove the surge protection from a UPS ? evolutionX General Electronics Chat 41 09-20-2008 02:33 PM
ups help mfaheemkhan6 General Electronics Chat 3 09-01-2008 05:41 PM
ups using oscillator ic cd 4047 THD PROBLEM adeel General Electronics Chat 1 07-30-2008 12:54 PM
Modifying the BCPERS300 ups pooky General Electronics Chat 2 01-21-2008 03:22 PM

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 09:23 PM.


User-posted content, unless source quoted, is licensed under a Creative Commons Public Domain License.
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.