Correct PSU Wiring - diyAudio
Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 9th October 2002, 09:04 PM   #1
Rarkov is offline Rarkov  England
diyAudio Member
 
Rarkov's Avatar
 
Join Date: Aug 2002
Location: North East, UK
Send a message via ICQ to Rarkov Send a message via Skype™ to Rarkov
Default Correct PSU Wiring

Hi,

I have attached an image of my understanding of a PSU connection. The bit I'm not sure about is the Earth wire. I know it's not strictly needed - but I'd prefer to have it there. These question apply for the UK - but they may be universal?

1) Do I need to attach Neutral to the Earth?

2) Is Ground and Earth the same thing?

3) What is the pinout for a three pin computer/kettle etc. cable (in the UK only?)

4) Are there any problems with the circuit as it stands?!

Thanks - please help me from blowing myself up!

Gaz
Attached Images
File Type: jpg psu.jpg (60.7 KB, 328 views)
  Reply With Quote
Old 9th October 2002, 11:02 PM   #2
Warp Engineer
On Holiday
 
AudioFreak's Avatar
 
Join Date: Oct 2001
Location: Queensland, Australia
This should answer a few of your questions

The earth wire should not be connected to your circuit as you have it.

All power should return to Neutral. Earth should be connected to the chassis. You should also separate the signal ground from the power ground.
  Reply With Quote
Old 10th October 2002, 06:06 PM   #3
Rarkov is offline Rarkov  England
diyAudio Member
 
Rarkov's Avatar
 
Join Date: Aug 2002
Location: North East, UK
Send a message via ICQ to Rarkov Send a message via Skype™ to Rarkov
Hi

The reason I did the diagram like that is because I thought the Earth went to the chassis and so did the HQG. Isn't that connected to ground too? Meaning that the Ground and Earth are all connected together.

But I need to connect the Neutral there aswell?

Thanks

Gaz
  Reply With Quote
Old 10th October 2002, 06:56 PM   #4
diyAudio Member
 
Sparhawk's Avatar
 
Join Date: Sep 2002
Location: Ontario, Canada
Grounding can be confusing... There are the safety issues, and then the noise issues.

I'm not an expert, but here is my understanding:

The neutral should NOT be connected to the "Earth". The "Earth" connection is a safety ground - it should be connected to the chassis, and no current should flow through it under normal circumstances. It is there in case the Live wire should somehow contact the chassis. In this case, current will flow through the saftey ground and the fuse or breaker will trip, ensuring that the chassis doesn't become a shock hazard.

The centre tap on the transformer is a floating "common", or zero volt point. This is where your speaker return should connect. Your input return connects here too, though perhaps not physically - maybe it is better to physically connect the input return to the amp pcb? I'm not sure.

Now, as to whether the transformer common should connect to the chassis... Probably not directly. Maybe through a resistor or a rectifier, to eliminate noise.
  Reply With Quote
Old 10th October 2002, 07:09 PM   #5
diyAudio Member
 
Join Date: Aug 2002
Location: CA
My opinions to your questions:
1.) No- it's already connected at your service panel.
2.) Yes -Ground (USA) Earth (GB)
3.) N/A
4.) a. Maybe--- depending on your xfmr/design, the two primary windings should be wired in parallel---not in series as you have drawn. (Assuming a standard four winding torid xfmr)
b. The secondary as drawn looks fine to me "if" the ground wires as shown are executed in the "star" method.
Good Luck!
  Reply With Quote
Old 10th October 2002, 07:37 PM   #6
Rarkov is offline Rarkov  England
diyAudio Member
 
Rarkov's Avatar
 
Join Date: Aug 2002
Location: North East, UK
Send a message via ICQ to Rarkov Send a message via Skype™ to Rarkov
Hi,

Orcad wasn't set up to plot at angles so that's why it isn't in star form. As for the xformer...

It is a 2x115V primary so for 240V UK use, the primaries have to be in series.

Is it right that the Earth connects to the chassis / HQG point?

Thanks,
Gaz
  Reply With Quote
Old 10th October 2002, 08:11 PM   #7
diyAudio Member
 
Sparhawk's Avatar
 
Join Date: Sep 2002
Location: Ontario, Canada
As I mentioned before, the Earth (or Ground) MUST connect to the chassis for safety reasons. The "HQG" point should probably not be directly connected to the chassis for noise reasons - usually it is connected via a resistor or rectifier.

Take a look at the power supply schematic on this page (from passdiy.com):

http://www.passdiy.com/projects/zenv4-4.htm

Here you can see what I mean about connecting the common through a rectifier to the chassis.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Help finding correct amp plus wiring dilema. gixxierific Car Audio 7 15th November 2008 01:01 PM
correct box? dallaire Multi-Way 2 31st December 2007 07:25 PM
Focusing on wiring cable for gainclone!!!Share ur experience in wiring cable.... thomgun_lc Chip Amps 38 31st August 2005 02:46 PM
I'm wiring my 4 channel 8 parallel LM4780 boards... check my wiring :) Audiophilenoob Chip Amps 9 16th August 2005 04:37 AM
This crossover wiring correct? Rufes1 Multi-Way 6 5th February 2004 03:46 AM


New To Site? Need Help?

All times are GMT. The time now is 08:07 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2