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Equi=Core Hum & Other Issues

I’ve owned a Core Power Tech Equi=Core 1800 for 6 months. Recently the transformer has started to hum inside the chassis. It happens when components are on and also when sources are powered down. The transformer hum is intermittent. It ranges from multiple times per day to 3 or 4 days without any hum. I never had DC on my dedicated lines before, so I picked up a Klein Tools AC/DC tester... https://www.kleintools.com/catalog/electrical-testers/electronic-acdc-voltage-tester-12-240v-ac-15-2...
and when plugged into wall receptacles it indicated overload. Line voltage is steady at 122VAC and always has been.
What am I doing wrong, and how should I test for DC on the power line?

I discovered another problem when testing the Equi=Core duplex receptacles; they indicate inverted polarity. All house outlets measure correct polarity.
I’m looking for some assistance in diagnosing this hum. I’m not sure if it’s due to DC offset or if the torroid itself is vibrating in its mounting.

I know this is becoming a long thread, but I must mention that the Equi=Core now trips the breaker at the panel when powered on. It trips several times in a row, eventually allowing power-up. This is a 20A dedicated line from a subpanel which I’ve had for years.
Any advice is much appreciated.


128x128lowrider57
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lowrider57 OP
5,417 posts
 
@jea48 
Hi Jim. I had a good look at my outside power hookup.

There are 3 lines from the pole that run parallel to all the rowhomes; 2 heavy gauge, one thin cable. They are mounted to the rear wall and extend about 15" outward and 12" below the square weatherhead. 

The service drop consists of two black cables and one white. The drop is U-shaped but the black cables enter the side of the weatherhead and terminate inside. They are horizontal at the point of entry.
The white cable hookup looks like your diagram and enters the bottom of the box.

I'm awaiting your reaction to these findings. Thanks. 



jea48
4,484 posts
 
There are 3 lines from the pole that run parallel to all the rowhomes; 2 heavy gauge, one thin cable. They are mounted to the rear wall and extend about 15" outward and 12" below the square weatherhead.
Wow.

Well, it sounds like the utility power lines are below the " square weatherhead". That’s good.....

The service drop consists of two black cables and one white. The drop is U-shaped but the black cables enter the side of the weatherhead and terminate inside. They are horizontal at the point of entry.
"The drop is U-shaped but the black cables enter the side of the weatherhead and terminate inside."

weatherhead? Sounds more like a junction box. How big is the box? Just a guesstimate.


The drop is U-shaped but the black cables enter the side of the weatherhead and terminate inside. They are horizontal at the point of entry.
I have no idea what you have.... No Idea.... Has to be really old though.
What stops the rain from blowing in through the side of the box where power wires enter?
I assume the box is surface mounted? Is there a conduit that drops out of the bottom of the box?


The white cable hookup looks like your diagram and enters the bottom of the box.
240V Lines enter through the side of the box, and the white neutral wire enters from the bottom of the box. Correct?
Is the box made of steel?
.
lowrider57's avatar
lowrider57 OP
5,417 posts
 
@jea48 
I have no idea what you have.... No Idea.... Has to be really old though.
What stops the rain from blowing in through the side of the box where power wires enter?
I assume the box is surface mounted? Is there a conduit that drops out of the bottom of the box?
It is very old. This is an old neighborhood which used to have blackouts during storms. We finally got new transformers on the poles. Power is stable and higher now, 122-124VAC.

Nothing stops the rain from entering the box. The black cables from the drop make a 90° turn and enter through 2 holes on the exposed side. The white neutral enters through the bottom and keeps a perfect U- shape.
What's interesting is the electrician knew exactly where the water leak was. I was looking at the meter and he said no, it comes from up there.
I'm going to take pics. I'll try and post them for you over the weekend.

The box is surface mounted and looks like steel, about 6" x 4". The conduit drops out of the bottom and is very weathered looking; really beat up. 

I'm going to check out the hookups on some other homes.
Jim, I always appreciate your help.
Jim S.

lowrider57's avatar
lowrider57 OP
5,417 posts
 
@jea48 
These are pics of my service drop connection to my mains.

https://ibb.co/qpQnYf5 https://ibb.co/VVzq1W5 https://ibb.co/JCsg9jj https://ibb.co/Y3ynkkq


lowrider57's avatar
lowrider57 OP
5,417 posts
 
All the other rowhomes have this type of connection. 


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