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This past week, I was suddenly greeted with my 'forever stable' 100A 3-phase Digital Power Analyzer (Magtrol 4614B) freaking out, that I've had on my power cart for the past 15 years, with my Superior Electric 0-140V/30A 'variac' sitting atop it. When I moved into the shop back in March of 2009, after getting benches set up in this long narrow 30ft by 10ft space with 12ft ceilings and a 60A AC Mains Service installed with quad boxes lining the West Wall, along with a 120V/30A and a 240V/30A service outlets, I used the 240V outlet to feed my 5kVA Topaz isolation xfmr, strapped 240V in/120V out to yield even greater than 30A 120V AC mains if/when needed (worked on a number of QSC 6001's and 9001 humoungous wattage power amps).
This past Wednesday that analyzer, which does have GPIB interface provisions (which I don't use), the front panel control ranges began randomly changing settings along with the digital display readings also scrolling irrational numbers. My heart sort of sank, pondering that I knew the day would eventually come when something like that would happen. Ended up turning it off and moved the smaller Valhalla 2001 20A Digital Power Analyzer over from the check-out bench and set it alongside precariously balanced partially on the bench to the left of the Powerstat. Plugged the Output of the Powerstat into the Valhalla, still be sourced from the Topaz 240V in/120V out. It was behaving fine, no interference issues with it.
I turned the Magtrol analyzer back on, and it now not connected to any voltage source (other than AC mains to make it run), no randomly dancing control buttons nor display readings. Interesting.
I then unplugged the 30A 120V source cable that goes up and over the walkway thru the narrow/long shop to the DEC 30A power panel that provides AC Mains to the East Side of the room to feed various items, and a couple feet south of it is a smaller Weston AC Line Monitor plugged in. I plugged the Powerstat 'Variac' into that vacated 30A/120V outlet and then the output of the Variac into the Magtrol 4614B. NOW working fine, just like it has for the past 15 years. I then plugged the DEC power cable into the output from the Topaz 5kVA Power Xfmr. I had power again on the East Wall, though no longer have the dual Neon Lamps lit on the panel that I did have prior to changing voltage sources. Had 120VAC reading on the Weston Line Meter, and the breaker switch toggled the panel on and off just fine.
NOW, WHAT's GOING ON HERE?
During the week, in our lobby for Studios 1, 2 and 3 in the North Side of the street building of our 12-rehearsal studio complex, Victoria Whit was given free rein to put up large images she has painted and installed the large monochromatic portraits of the iconic figures who inspire her. And most of the large images now have bright florescent text lining the portraits, along with a blue-painted baby grand piano with a picture of Paul McCartney on the top of the piano, replacing the traditional black baby grand that had been there over the years.
All the powering of the lighting was by way of current-technology low-cost 0-12VDC/5A power supplies with digital readouts, all set for around 9.3 to 9.6VDC to run them.
The interference I was seeing on my Magtrol power analyzer appears to have started when these cheap Chinese power supplies were plugged in to power the lighting on her images (putting two and two together to get a possible understanding of what was happening at the opposite end of the hallway where my shop is located).
I haven't yet heard if any of our clients that are using Studio 3, which is entered thru the lobby there, or those using Studios 1 & 2 down the hallway from the lobby (larger rehearsal rooms) in this building have begun having any of their digital gear freaking out. I don't know if this will happen. I also haven't yet worked backwards, restoring the connections of my analyzer to the output of the Topaz isolation xfmr and then going back to the lobby to unplug those cheap power supplies, temporarily shut off the lighting for the paintings, and see if the problem with the Magtrol Analzyer stops.
There's one thing that I never did try and repeat with regards to the Topaz 5kVA Transformer. I once tried grounding one side of the 120V output to case GROUND to establish Grounded Neutral. (The two isolated 120V xfmr windings were strapped in parallel for twice the current). Plugging it back into 240V input and it tripped the building breaker. Never tried that again, so it's been floating 120V output to this day.
The 120V/30A service where I have the 30A 'variac' plugged in IS a grounded neutral mains source, and the Magtrol is once again stable and happy. IS THERE something about these cheap Chinese power supplies that have been introduced into the building's power for the paintings that has caused my power analyzer, which WAS fed from a non-grounded xfmr-isolated voltage source to 'freak out'?
This past Wednesday that analyzer, which does have GPIB interface provisions (which I don't use), the front panel control ranges began randomly changing settings along with the digital display readings also scrolling irrational numbers. My heart sort of sank, pondering that I knew the day would eventually come when something like that would happen. Ended up turning it off and moved the smaller Valhalla 2001 20A Digital Power Analyzer over from the check-out bench and set it alongside precariously balanced partially on the bench to the left of the Powerstat. Plugged the Output of the Powerstat into the Valhalla, still be sourced from the Topaz 240V in/120V out. It was behaving fine, no interference issues with it.
I turned the Magtrol analyzer back on, and it now not connected to any voltage source (other than AC mains to make it run), no randomly dancing control buttons nor display readings. Interesting.
I then unplugged the 30A 120V source cable that goes up and over the walkway thru the narrow/long shop to the DEC 30A power panel that provides AC Mains to the East Side of the room to feed various items, and a couple feet south of it is a smaller Weston AC Line Monitor plugged in. I plugged the Powerstat 'Variac' into that vacated 30A/120V outlet and then the output of the Variac into the Magtrol 4614B. NOW working fine, just like it has for the past 15 years. I then plugged the DEC power cable into the output from the Topaz 5kVA Power Xfmr. I had power again on the East Wall, though no longer have the dual Neon Lamps lit on the panel that I did have prior to changing voltage sources. Had 120VAC reading on the Weston Line Meter, and the breaker switch toggled the panel on and off just fine.
NOW, WHAT's GOING ON HERE?
During the week, in our lobby for Studios 1, 2 and 3 in the North Side of the street building of our 12-rehearsal studio complex, Victoria Whit was given free rein to put up large images she has painted and installed the large monochromatic portraits of the iconic figures who inspire her. And most of the large images now have bright florescent text lining the portraits, along with a blue-painted baby grand piano with a picture of Paul McCartney on the top of the piano, replacing the traditional black baby grand that had been there over the years.
All the powering of the lighting was by way of current-technology low-cost 0-12VDC/5A power supplies with digital readouts, all set for around 9.3 to 9.6VDC to run them.
The interference I was seeing on my Magtrol power analyzer appears to have started when these cheap Chinese power supplies were plugged in to power the lighting on her images (putting two and two together to get a possible understanding of what was happening at the opposite end of the hallway where my shop is located).
I haven't yet heard if any of our clients that are using Studio 3, which is entered thru the lobby there, or those using Studios 1 & 2 down the hallway from the lobby (larger rehearsal rooms) in this building have begun having any of their digital gear freaking out. I don't know if this will happen. I also haven't yet worked backwards, restoring the connections of my analyzer to the output of the Topaz isolation xfmr and then going back to the lobby to unplug those cheap power supplies, temporarily shut off the lighting for the paintings, and see if the problem with the Magtrol Analzyer stops.
There's one thing that I never did try and repeat with regards to the Topaz 5kVA Transformer. I once tried grounding one side of the 120V output to case GROUND to establish Grounded Neutral. (The two isolated 120V xfmr windings were strapped in parallel for twice the current). Plugging it back into 240V input and it tripped the building breaker. Never tried that again, so it's been floating 120V output to this day.
The 120V/30A service where I have the 30A 'variac' plugged in IS a grounded neutral mains source, and the Magtrol is once again stable and happy. IS THERE something about these cheap Chinese power supplies that have been introduced into the building's power for the paintings that has caused my power analyzer, which WAS fed from a non-grounded xfmr-isolated voltage source to 'freak out'?
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