AudioCircle
Audio/Video Gear and Systems => Power Conditioning => Topic started by: Sandrock on 15 Jul 2017, 10:04 pm
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I have a Clear Image Audio T4 Power Line Isolator and with the advent of some new equipment and PC cables I was wondering if everything was in phase equipment-wise. So I got the bright idea to use an Outlet Tester on the treated end (output) of the T4 to see which way the phase switch needed to be switched to be in phase. (there is no marking as to which way to press the rocker switch). Well to my surprise when I used the Outlet Tester it registered that all 4 of the receptacles have an "open" ground! I must admit I am confused? If they are all open ground then how does the 3 pin plug work ground-wise?
Can I suggest that there might be someone to see if what I have explained it correct with all Power Conditioners or is it just mine that might not be working correctly.
It would sure be a BIG help and relief to me to find out the truth! Do I have nothing to worry about OR do I have something to worry about???
My equipment is plugged into the unit and works fine however when I change the rocker switch I hear no sound difference.
Please can someone help out with this issue I am experiencing? I have posted a couple of pictures to fully understand what I am speaking about.
(http://www.audiocircle.com/image.php?id=165560)
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Portable, corded isolation transformers have different NEC & UL rules than permanent hard wired isolation transformers. I'll get back to this Sunday.
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Although these photos are of the SE edition, it appears the only difference is an upgrade to some wiring and parts. Interesting that it has a separate transformer for each simplex receptacle as well as a phase reversal switch on the back for each.
(http://www.audiocircle.com/image.php?id=165563)
(http://www.audiocircle.com/image.php?id=165564)
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Thank you Speed Skater, I look forward to hearing your findings tomorrow.
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SRB, I have the regular unit, not the SE version.
That came out a little later.
I think the 4 transformers are there because they wanted to provide individual isolation from the other components plugged into the T4.
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I think the 4 transformers are there because they wanted to provide individual isolation from the other components plugged into the T4.
Right, but other components I've see like this most often have individual filter banks all running off of one large isolation transformer.
I'm interested to see how the safety ground figures in which won't be inductively coupled through the transformers like the active hot and neutral lines.
Steve
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Me too Steve!
That's why I am questing this issue and want to get to the bottom of exactly what is going on.
It bothers me to stick the outlet tester in the receptacle and see an open ground! I just finished spending a lot of money on high performance three prong power cords, only to find out that the ground is not there!
This is what confuses me.
"I want answers"!!!!!! ha.
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Steve, is that your T4 in the pictures?
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No, I was just curious about the unit and its componentry and grabbed a couple pics off the net.
Steve
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Gotcha ........
Ian
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Rig up a test light... so you can see if the hot to ground lights up the bulb.
It may be crude, but at least you know then that the power can go to ground.
Testing in this way may also set off any ground fault interrupter...
Personally I think the device is just not built right to test power conditioners with complex innards.
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I have a Clear Image Audio T4 Power Line Isolator and with the advent of some new equipment and PC cables I was wondering if everything was in phase equipment-wise. So I got the bright idea to use an Outlet Tester on the treated end (output) of the T4 to see which way the phase switch needed to be switched to be in phase. (there is no marking as to which way to press the rocker switch). Well to my surprise when I used the Outlet Tester it registered that all 4 of the receptacles have an "open" ground! I must admit I am confused? If they are all open ground then how does the 3 pin plug work ground-wise?
Can I suggest that there might be someone to see if what I have explained it correct with all Power Conditioners or is it just mine that might not be working correctly.
It would sure be a BIG help and relief to me to find out the truth! Do I have nothing to worry about OR do I have something to worry about???
My equipment is plugged into the unit and works fine however when I change the rocker switch I hear no sound difference.
Please can someone help out with this issue I am experiencing? I have posted a couple of pictures to fully understand what I am speaking about.
(http://www.audiocircle.com/image.php?id=165560)
There is a good possibility the unit has each out put of the isolation transformers floating above ground. If this is the case there will not be a reference to ground from either output Line, leg, of the iso transformers. That would explain the "open ground".
Will post later in greater detail
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OK, in a portable, corded 'point of use' isolation transformer, there is no DC continuity from the Safety Ground to the Hot or Neutral. So the little 3 LED has no ground reference. Situation normal.
By the way those little testers are not very smart, they don't know about bootleg grounds.
This by a pro audio guy:
"Failures in Outlet Testing Exposed"
http://www.ecmweb.com/contractor/failures-outlet-testing-exposed
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OK, in a portable, corded 'point of use' isolation transformer, there is no DC continuity from the Safety Ground to the Hot or Neutral. So the little 3 LED has no ground reference. Situation normal.
But I presume a multimeter would show continuity between the ground pin of the isolation unit receptacle and the ground pin of the wall receptacle?
Steve
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There is a good possibility the unit has each out put of the isolation transformers floating above ground. If this is the case there will not be a reference to ground from either output Line, leg, of the iso transformers. That would explain the "open ground".
Will post later in greater detail
To continue where I left off.
First I was unable to find any manufacture's info or wiring diagram of the unit in question. My comments are based solely on the test of the OP's using the circuit checker.
IF the iso, isolation, transformers secondary windings are floating above ground that means none of the outputs have any electrical reference to one another, or to chassis ground, or the safety equipment ground of the wall outlet mains power. Real power that is. Oh with a digital meter you may read some phantom voltage but it is basically meaningless, imo. It is also possible you may get a voltage reading from filters that are wired in the output circuit of an iso. Hard to know without a wiring diagram.
It also should be mentioned this type of floating power system an "Isolated AC Power System" should never be used in a non professional unsupervised setting. It is not for the untrained layman.
For use of the general consumer public the iso transformers separately derived outputs should have been wired making each output of each transformer a "Ground AC Power System". To accomplish this one output leg of each iso transformer is intentionally connected to the chassis along with the safety equipment grounding conductor from the 3 wire power cord. (There in the equipment grounding conductor in the AC power cord that feeds the unit.) The grounded leg conductor then becomes the Neutral, The Grounded Conductor. If the iso secondary outputs of the transformers had been wired this way the OP's circuit tester would not have given an open ground indication.
IF the Outputs are floating above ground there is no neutral. There are two floating Hot ungrounded output legs, conductors, with no reference to ground.
If the secondaries are wired correctly so the output is a "Grounded AC Power System" the plug-in tester should have indicated 'Correct'.
I would suggest a volt meter should be used.
At each receptacle outlet measure from the hot contact to the neutral contact. You should measure 120Vac nominal.
Next measure from the hot contact to the equipment ground contact of the receptacle. You should measure the same 120Vac nominal voltage as above. (No connected load.)
Next measure from the neutral contact to the equipment ground contact. You should measure zero volts.
Also each iso secondary should have been checked and wired so they would be in phase with one another. If in phase with one another there will not be a difference of potential, voltage, from the Hot contact from any receptacle to the hot contact to any other receptacle of the unit. If a 240V nominal voltage reading is measured from a hot to hot contact, from one receptacle to another, then they are not in phase.
As for the so called phase reversal switch. Beats me why the designer wanted to reverse the AC polarity, of what I believe is an "Isolated AC Power System".
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But I presume a multimeter would show continuity between the ground pin of the isolation unit receptacle and the ground pin of the wall receptacle?
Yes.
* * * * * * * * * * * *
To repeat myself:
Portable, corded isolation transformers have different NEC & UL rules than permanent hard wired isolation transformers.
If the secondaries are wired correctly so the output is a "Grounded AC Power System" the plug-in tester should have indicated 'Correct'.
Only for a permanent hard-wired transformer is this true. Not so for a portable unit.
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From a Bill Whitlock seminar paper.
(http://www.audiocircle.com/image.php?id=165586)
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From a Bill Whitlock seminar paper.
(http://www.audiocircle.com/image.php?id=165586)
Great picture showing an "Isolated AC Power System".
Note the secondary of the isolation transformer is floating above ground. The current carrying contacts of the receptacle are fed with two Hot ungrounded conductors.
Imagine 4 of these things feeding audio equipment that is connected together by RCA interconnects.
Speedskater,
Thanks for the picture.
How about a link to the rest of Bill's white paper, the picture was taken from. I would like to read his comments on using an Isolated AC Power System to feed home consumer audio equipment.
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But I presume a multimeter would show continuity between the ground pin of the isolation unit receptacle and the ground pin of the wall receptacle?
Yes.
* * * * * * * * * * * *
To repeat myself:
Portable, corded isolation transformers have different NEC & UL rules than permanent hard wired isolation transformers.
If the secondaries are wired correctly so the output is a "Grounded AC Power System" the plug-in tester should have indicated 'Correct'.
Only for a permanent hard-wired transformer is this true. Not so for a portable unit.
Only for a permanent hard-wired transformer is this true. Not so for a portable unit.
An Isolated Power System should only be used by qualified personnel or under the supervision of qualified personnel.
Usually a cord and plug UL Listed Isolated Power System iso transformer will be labeled as a Medical Isolation transformer. You use to see these on a service tech's bench, still may. You will also see them in hospitals. Again, under the supervision of qualified personnel.
As for your comment you only see Grounded AC system iso transformers hard wired you are mistaken.
Just Curious if you know if the OP's unit is UL Listed to be sold to the retail market consumer? Not that it is not being marketed to the retail consumer, but is it UL Listed for the purpose?
EDIT:
Not that it is not being marketed to the retail consumer, but is it UL Listed for the purpose?
That should read,
Not that it is not being marketed to the retail consumer, but is it Listed by any recognized third party safety testing Labotory for the purpose?
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Hello all,
I have been busy today so now is the first time to touch the keyboard.
In answer to your interesting question jea48, I did a quick check and nothing is mentioned anywhere on the unit about it being UL Listed. My guess is that the cost and time for listing did not outweighs the number they expected to sell. Audio Prism felt that the number they would sell was not worth the cost to obtain the status.
But that is just conjecture on my part.
I appreciate all those who have stepped up to help move forward my original question.
It has been very enlightening.
So Speedskater, you are suggesting that the unit might have a "bootleg ground"?
How interesting.
I must say that I am not quite sure exactly what that means.
I have an idea but I am not real clear that I can wrap my mind around it.
Given all that has been posted before, are you saying that in spite of what I originally asked, perhaps my unit is functionally working correctly?
Great news if that were to be true.
I agree about why they put a rocker switch at all 4 of the outlets to change the phase. But perhaps it helps what ever is plugged into the socket to sound better.
But again its just supposition on my part. Given how electronic equipment is designed it would seem somewhat redundant. Maybe its the Rolls Royce of Isolation Conditioners. Won't that be a hoot?
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Hello all,
I have been busy today so now is the first time to touch the keyboard.
In answer to your interesting question jea48, I did a quick check and nothing is mentioned anywhere on the unit about it being UL Listed. My guess is that the cost and time for listing did not outweighs the number they expected to sell. Audio Prism felt that the number they would sell was not worth the cost to obtain the status.
But that is just conjecture on my part.
I appreciate all those who have stepped up to help move forward my original question.
It has been very enlightening.
So Speedskater, you are suggesting that the unit might have a "bootleg ground"?
How interesting.
I must say that I am not quite sure exactly what that means.
I have an idea but I am not real clear that I can wrap my mind around it.
Given all that has been posted before, are you saying that in spite of what I originally asked, perhaps my unit is functionally working correctly?
Great news if that were to be true.
I agree about why they put a rocker switch at all 4 of the outlets to change the phase. But perhaps it helps what ever is plugged into the socket to sound better.
But again its just supposition on my part. Given how electronic equipment is designed it would seem somewhat redundant. Maybe its the Rolls Royce of Isolation Conditioners. Won't that be a hoot?
"In answer to your interesting question jea48, I did a quick check and nothing is mentioned anywhere on the unit about it being UL Listed. My guess is that the cost and time for listing did not outweighs the number they expected to sell. Audio Prism felt that the number they would sell was not worth the cost to obtain the status.
But that is just conjecture on my part.
Technically it does not have to be safety tested, and Listed, by UL. It could be safety tested and Listed by any recognized third party testing Laboratory. Question is, what was the manufacture's intended market for the unit to be used in when submitting the unit for safety testing? Was it stated for home consumer use?
Also there is the possibility the unit was not safety tested by any recognized third party Lab, as you stated in your post.
If you do not own a multi meter I would suggest you buy one. You should check each of the 4 separately derived Isolated Power systems on a regular basis to make sure both Hot power lines, legs, of each AC power system is floating above ground. If for any reason one of the two hot power lines, of any of the 4 AC power systems, were to go to ground you would not know it happened. (That is unless each of the 4 Isolated AC Power Systems has a line monitor that monitors both lines and alerts the user with some kind of warning, either by and indicating light or audible sound or both. Or the monitor shuts down the affected power supply.) Other wise the affected power supply would continue to supply AC power to its' connected load. It could be the hot line that is connected to the neutral terminal on a receptacle, OR it could be the hot line that is connected to the Hot side terminal of the receptacle. The ground fault could occur inside the unit, in the power cord plugged into the outlet, or inside the piece of audio equipment the AC power supply is feeding.
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So Speedskater, you are suggesting that the unit might have a "bootleg ground"?
No, the opposite! That's correct operation for a portable I.T.
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Links to Bill Whitlock papers:
Generic Student Seminar Handout AN007
http://www.jensen-transformers.com/login
"UNDERSTANDING, FINDING, & ELIMINATING GROUND LOOPS IN AUDIO & VIDEO SYSTEMS"
2012 Seminar
"An Overview of Audio System Grounding & Interfacing"
https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf
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Links to Bill Whitlock papers:
Generic Student Seminar Handout AN007
http://www.jensen-transformers.com/login
"UNDERSTANDING, FINDING, & ELIMINATING GROUND LOOPS IN AUDIO & VIDEO SYSTEMS"
2012 Seminar
"An Overview of Audio System Grounding & Interfacing"
https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf
Thanks for the links. I was already quite familiar with this one. Which I credit you with posting it a few years back.
2012 Seminar
"An Overview of Audio System Grounding & Interfacing"
https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf
Though I had forgotten seeing the picture/diagram you furnished in an earlier post. I found it on page 200, with a few comments given by Bill.
This link also provides good info.
http://www.middleatlantic.com/resources/white-papers.aspx
"Power Distribution and Grounding of Audio, Video and Telecommunications Equipment White Paper"
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In the Spring, there was another similar thread, in another forum that had a Bill Whitlock schematic of the two ways the Safety Ground may be connected to an I.T.
But I can't find the thread or the Bill Whitlock paper.
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Hello everyone,
You all have raised some good points and they are worth thinking about.
In my original question I asked if anyone could do the same test a I did with an "outlet tester" plugged into their line conditioner and report back their findings.
Should they come to the same findings as I did with their own outlet tester and power-line conditioner it would substantiate Elizabeth's comment "I think the device is just not built right to test power conditioners with complex innards."
Especially given both Speedskater and jes48's informative scientific posts regarding the subject.
I just wish we could get 'real-world' physical proof of the same findings as I got.
Please, is there anyone who would like to volunteer to do the quick test on behalf of the group?
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Remember that this unusual 3 LED tester result only applies to units that have a:
'Portable, corded isolation transformer'.
All other units should have the correct LED's lite.
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True, however I am most interested in the results of power-line conditioner like I have.
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Here are 3 wiring diagrams for Bryston Power Conditioners.
Note all 3 are Grounded Power Systems. One leg of the isolation transformer is intentionally connected to ground.
The plug in polarity/ground circuit tester will indicate 'Correct'
http://bryston.com/PDF/Schematics/BIT_RM_15_(PA-10768-00)_SCHEMATIC.pdf
http://bryston.com/PDF/Schematics/BIT_RM_20_(PA-9131-00)_SCHEMATIC.pdf
http://bryston.com/PDF/Schematics/BIT_RM_20_BAL_SCHEMATIC.pdf
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Hello everyone,
You all have raised some good points and they are worth thinking about.
In my original question I asked if anyone could do the same test a I did with an "outlet tester" plugged into their line conditioner and report back their findings.
Should they come to the same findings as I did with their own outlet tester and power-line conditioner it would substantiate Elizabeth's comment "I think the device is just not built right to test power conditioners with complex innards."
Especially given both Speedskater and jes48's informative scientific posts regarding the subject.
I just wish we could get 'real-world' physical proof of the same findings as I got.
Please, is there anyone who would like to volunteer to do the quick test on behalf of the group?
Kind of late to be asking the question, this far into thread now, but did you plug the polarity/ground circuit tester in at least a couple 3 prong grounded wall outlets in your home to make sure the device works properly? It indicated Correct?
As for proof with the unit you have any electronic tech, or electrician, could pull the top cover of the unit and see if the unit is truly wired as an Isolated AC Power System.
There in the secondary outputs of the 4 separately derived iso transformers are floating above ground.
There should be a consumer rights law here in the US that makes the manufacture install a label on the back panel of the unit,
WARNING: ISOLATED AC POWER SYSTEM.
Output floating above ground.
For use by qualified personnel only.
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Hello Jea48, its sometimes funny that in our hast to get to the answer of the question we bypass the most obvious such as switching the unit on or something as simple as just plugging the equipment into the wall socket, right?
Well I wanted to make sure that before I posted I had all my ducks lined up so not only did I do as you suggested but just on the off chance that my older primary tester was defective I purchased a new tester ( the one in the picture) to double check first with both of them. Plus I went around the house checking most of the outlets, just to make sure everything was on the up and up so to speak and was in correct working condition. I found no problems. I am not sure it is possible to discern your answer from a picture I took last month of the unit I have with the cover off. Check it out and see if you can tell.
Cheers
(http://www.audiocircle.com/image.php?id=165702)
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It would take a high resolution camera and studio lighting to puzzle out the wiring.
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Yeah, I also noticed that same issue too. I will see what I can do but as you can fully understand its a real chore to unplug and get the unit out. But never the less I will do my best. So lets see what happens.
Cheers
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Yeah, I also noticed that same issue too. I will see what I can do but as you can fully understand its a real chore to unplug and get the unit out. But never the less I will do my best. So lets see what happens.
Cheers
I would have to have the thing setting in front of me to quickly trace, follow, the two secondary leads from the transformers to the output receptacle outlets.
If you have a multi meter, as I stated in an earlier post, you can verify 100% the output of each transformer is left floating above ground.
Did you buy the unit new?
If so contact the dealer and ask him what he knows about the unit. If he tells you he doesn't know anything about it ask him if there is a tech support contact, for the unit, you can ask.
They may provide a wiring diagram of the unit. There is nothing top secrete under the top cover of the unit.
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It would take a high resolution camera and studio lighting to puzzle out the wiring.
It would help. I was able to see a better, brighter, picture on my cell phone than my PC monitor.
I can see the equipment ground for each receptacle outlet is an individual green grounding conductor that connects from each receptacle to a common ground stud on the metal chassis. (Lower left of the picture)
I see what appears to be a DPDT rocker switch that is configured, wired, for the "phase" reversal option for each output receptacle.
On the back of each receptacle there appears to be something wired to the receptacles that are shaped something like two resistors. The picture is not good enough. A closeup picture with better light of only one receptacle, the "phase" reversal rocker switch, and the AC filter (side closest to the receptacle) all in one picture would help.
The only thing that separates this Separately Derived iso 4 transformer power conditioner from being an Isolated AC Power System from a Grounded AC Power System is a bonding jumper wire from the neutral terminal on each receptacle outlet to the equipment grounding terminal on each outlet. Simplest way, without changing the existing wiring in the unit, to a Grounded AC Power system.
Do you see a problem with what I propose?
Does it change in any way how the AC noise filters, on the secondaries of the transformers function? (Of course if it does, the same would happen in the event of a Hot to chassis ground fault on a Hot Line, leg, to ground in a piece of connected equipment. It would have the same result.
Next question, and the one the people that design and target floating AC iso power systems to be sold to the unknowing retail consumer to power home audio equipment, does it really improve the SQ of an audio system over a properly iso grounded AC power system?
Apparently Brytson doesn't think so.
http://bryston.com/PDF/Schematics/BIT_RM_20_(PA-9131-00)_SCHEMATIC.pdf
Your thoughts please.
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Well it's not a 'Separately Derived System'. In fact it's not a system at all, it's a portable, corded 'point of use' isolation transformer. If you ground the Neutrals, you will have to eliminate to polarity rocker switches.
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Well it's not a 'Separately Derived System'. In fact it's not a system at all, it's a portable, corded 'point of use' isolation transformer. If you ground the Neutrals, you will have to eliminate to polarity rocker switches.
Well it's not a 'Separately Derived System
Your definition of a separately derived power system?
Is the secondary of the isolation transformer electrically connected to the primary? Does the secondary output of an isolation transformer have any electrical reference to the source feeding the transformer when the secondary is left floating above ground? (Yes I understand without the feed energized power source there is not an output power source.)
If you ground the Neutrals, you will have to eliminate to polarity rocker switches.
Why? The switch/s reverses the polarity of the secondary winding power as fed to the receptacle. The proper HOT and Neutral orientation polarity at the receptacle is not changed. The switch just flips the two ungrounded 120Vac secondary leads that feed the receptacle. Correct? That is why the neutral would be bonded to ground at the receptacle after the reversal switch.
Note:
As for the "phase" reversal switch.... I really don't see any useful need/reason why it was incorporated in the design of the unit. All the builder of the unit had to do was make sure all of the outputs at the receptacle outlets were all in phase with one another.
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Now those are two good questions! I'll have to think about them a lot.
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Hello everyone, this morning my plan is to unhook the T4, open it up and shoot some well lighted close ups to share.
Give me about 90 minutes or so......
Cheers
Ian
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Back at the keyboard and in 72 minutes, well under my 90 min quote....Ha!
Anyway I have a bunch of pictures of the guts of the T4 which I hope will shed some light on this vexing question.
They are in no perticular order and a few of them might be overlapping info-wise.
(http://www.audiocircle.com/image.php?id=165742)
(http://www.audiocircle.com/image.php?id=165743)
(http://www.audiocircle.com/image.php?id=165744)
(http://www.audiocircle.com/image.php?id=165747)
(http://www.audiocircle.com/image.php?id=165748)
(http://www.audiocircle.com/image.php?id=165749)
(http://www.audiocircle.com/image.php?id=165750)
(http://www.audiocircle.com/image.php?id=165751)
(http://www.audiocircle.com/image.php?id=165752)
(http://www.audiocircle.com/image.php?id=165753)
(http://www.audiocircle.com/image.php?id=165754)
(http://www.audiocircle.com/image.php?id=165755)
(http://www.audiocircle.com/image.php?id=165756)
(http://www.audiocircle.com/image.php?id=165757)
(http://www.audiocircle.com/image.php?id=165758)
(http://www.audiocircle.com/image.php?id=165759)
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Holly smokes Batman, I just viewed the pics and noticed that a bunch of them came in upside down. They were all right-side up and I made sure of that before I took the picture knowing that on the off chance the meta data might get screwed up...
So much for that idea. I hope you can still discern the information in-spite of some of them being USD!
Thanks,
Cheers
Ian
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Back at the keyboard and in 72 minutes, well under my 90 min quote....Ha!
Anyway I have a bunch of pictures of the guts of the T4 which I hope will shed some light on this vexing question.
They are in no perticular order and a few of them might be overlapping info-wise.
(http://www.audiocircle.com/image.php?id=165742)
(http://www.audiocircle.com/image.php?id=165743)
(http://www.audiocircle.com/image.php?id=165744)
(http://www.audiocircle.com/image.php?id=165747)
(http://www.audiocircle.com/image.php?id=165748)
(http://www.audiocircle.com/image.php?id=165749)
(http://www.audiocircle.com/image.php?id=165750)
(http://www.audiocircle.com/image.php?id=165751)
(http://www.audiocircle.com/image.php?id=165752)
(http://www.audiocircle.com/image.php?id=165753)
(http://www.audiocircle.com/image.php?id=165754)
(http://www.audiocircle.com/image.php?id=165755)
(http://www.audiocircle.com/image.php?id=165756)
(http://www.audiocircle.com/image.php?id=165757)
(http://www.audiocircle.com/image.php?id=165758)
(http://www.audiocircle.com/image.php?id=165759)
WOW!
I have no idea what the two 22 meg ohm resistors do that connect from each hot AC line on the receptacle/s to the equipment ground. :scratch:
Just a guess it has something maybe to do with noise filtering. :scratch:
22 meg ohm? That is right isn't it?
WOW! :?
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22M is also what I get, seems like that wouldn't do much.
We need a well lit overview of the whole thing though. Looks to me like the receptacles are all grounded to chassis. I'd test this with a multimeter between receptacle grounds and IEC inlet, ground should be straight through with very little resistance.
I'd expect results to vary a lot, the trafos are small and 2A capacity could be a problem with many components.
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22M is also what I get, seems like that wouldn't do much.
We need a well lit overview of the whole thing though. Looks to me like the receptacles are all grounded to chassis. I'd test this with a multimeter between receptacle grounds and IEC inlet, ground should be straight through with very little resistance.
I'd expect results to vary a lot, the trafos are small and 2A capacity could be a problem with many components.
~
Looks to me like the receptacles are all grounded to chassis. I'd test this with a multimeter between receptacle grounds and IEC inlet, ground should be straight through with very little resistance.
I agree. The power cord equipment grounding conductor connects to the grounding stud, seen in the picture/s, and from that stud individual green equipment ground wires run to and connect to the IG (Isolate Ground) equipment ground terminal screw on each IG ground Hubbell 15 amp single receptacle.
The unit, as is, should protect the user from any electrical shock hazard in the event of a Hot to chassis fault. Not only the power conditioner metal chassis but also the chassis of any equipment fed from the power conditioner, that uses the safety equipment ground, in the event either of the two secondary hot conductors were to come into contact with the metal chassis. Basically such a fault would make the fault of the wire contacting the chassis a grounded conductor. It could end up being the conductor feeding the safety fuse in a piece of audio equipment though.
Because the unit operates with 4 individual 120Vac floating power supplies I would not change any interconnects between audio equipment with any of the 4 power iso transformers energized. If more than one, or all energized, then the OP could receive an electrical shock. Bad enough one transformer's secondary is floating above ground. This has four 120Vac power supplies floating above ground. Definitely never use a ground cheater to lift the ground on a piece of equipment fed from the unit.
Dave,
Do you see a problem with removing the two 22m ohm resistors from each receptacle outlet and installing a bonding jumper from the neutral terminal on each receptacle to the equipment ground on each receptacle? This will ground the secondary lead that is connected to the neutral contact on the receptacle making it the "grounded conductor", the neutral conductor.
Then,
From neutral contact to Hot contact 120Vac nominal. Still the same.
From the Hot contact to the equipment ground contact, it will measure 120Vac nominal.
From the neutral contact to the equipment ground contact, zero Vac.
Resistance, continuity, check from the neutral contact to the equipment ground contact will measure OL, short.
The OP's polarity/ground circuit checker will indicate Correct when he checks each outlet.
The OP will need to check to make sure all 4 receptacles, transformers secondaries, are in phase with each other. In other wards from any hot to hot contact combination the voltage will measure zero volts nominal. If one or more reads 240Vac he will need to reverse the power leads feeding the odd receptacle/s. I would do this with all the "phase" rocker switches in the normal same position.
So what do you think? Worth the effort? The OP should be able to make the changes himself. An hour at the most, probably less.
As for the 2 amp max rating of each of the 4 transformers I just assumed the OP was aware of the fact.
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Sorry for the long hiatus from this thread (travel & sickness) debilitated me.
Anyway I continued to do some background research on the T-4 unit and contacted a long-time friend in San Diego who co-incidentally also purchased a unit as well.
I spoke to him (electrical engineer) at length and after him popping the hood off his unit he confirmed that what we have is a "line-isolator" and not a line-conditioner, which I already suspected.
We spoke further and deduced that everything is working as designed.
The initial problem I was asking about had to do with the little 'wall-outlet' tester and why the ground did not light up.
Well actually the outlet tester is designed for house use and not to test something like this piece of equipment.
So it was giving me a false reading which started raising red flags etc.
What that means is that there is no direct connection between the wall outlet and the connected pieces of equipment as normally thought. However they are in the end all working together but do not receive and of the noise/hash coming directly from the a/c outlet.
So no noise etc. is getting into my line level equipment.
Everything is grounded as designed and there is no worry of electrocution or fire etc.
The only problem was that the tester was misused in this test and gave out with a fault issue.
So all is good......
Thank you to all that participated in my quest for an answer to my own-created problem.
In the end one phone call did it all.
So the old adage is true.....its not what you know, but where to find the answer!
Cheers,
Ian
-
Sorry for the long hiatus from this thread (travel & sickness) debilitated me.
Anyway I continued to do some background research on the T-4 unit and contacted a long-time friend in San Diego who co-incidentally also purchased a unit as well.
I spoke to him (electrical engineer) at length and after him popping the hood off his unit he confirmed that what we have is a "line-isolator" and not a line-conditioner, which I already suspected.
We spoke further and deduced that everything is working as designed.
The initial problem I was asking about had to do with the little 'wall-outlet' tester and why the ground did not light up.
Well actually the outlet tester is designed for house use and not to test something like this piece of equipment.
So it was giving me a false reading which started raising red flags etc.
What that means is that there is no direct connection between the wall outlet and the connected pieces of equipment as normally thought. However they are in the end all working together but do not receive and of the noise/hash coming directly from the a/c outlet.
So no noise etc. is getting into my line level equipment.
Everything is grounded as designed and there is no worry of electrocution or fire etc.
The only problem was that the tester was misused in this test and gave out with a fault issue.
So all is good......
Thank you to all that participated in my quest for an answer to my own-created problem.
In the end one phone call did it all.
So the old adage is true.....its not what you know, but where to find the answer!
Cheers,
Ian
Well actually the outlet tester is designed for house use and not to test something like this piece of equipment.
Not true. It just doesn't work on "Isolated AC Power Systems".
It works as designed on "Grounded AC Power Systems".
They are used to check for correct polarity and for open ground in wall receptacle outlets in, office buildings, industrial facilities, hospitals (Other than in areas like procedure rooms like, CATH Labs, OR rooms, ER rooms, some X-ray rooms.), Malls, strip malls, about everywhere you can think of they are used.
What that means is that there is no direct connection between the wall outlet and the connected pieces of equipment as normally thought.
Other than the wall safety equipment ground. All the "U' ground contacts of the receptacles on the unit are connected to the equipment ground of the power cord that feeds the unit that plugs into the wall outlet.
Everything is grounded as designed and there is no worry of electrocution or fire etc.
You should have let the EE read this thread.
Best regards,
Jim