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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

Showing 7 responses by erik_squires

erik_squires
15,872 posts
 
Now, I should add that the electrician found corrosion on one leg in the meter outside due to water leakage


AHA!! :) I've read that corrosion can act as a diode. Lets see if this fixes it all. :) 
erik_squires
15,872 posts
 
Hey OP,

Those testers are very very simple devices that work well only with "normal" problems.

Chances are it looks for voltage on the neutral, and decides if it is there, that the voltage is inverted.

It doesn't know anything about balanced power. It's just very basic circuitry performing very simple IF...THEN calculations, and that is exaggerating the complexity already. :)

Best,

E
erik_squires
15,872 posts
 
You could have had a bad breaker this whole time.

Yes, it is possible to have DC in only 1 leg.

It can happen if a power supply sucks juice only on the positive, but not the negative cycle, on the same phase. I could also see something funky if  your neutral was loose, but it wouldn't be DC.


Best,

E
erik_squires
15,872 posts
 

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.


Oh, I missed this entirely. Have your circuit checked. You didn’t just go through a lot of ice or rain did you? :)

But it IS possible something blew in the conditioner too. You may have a short there you didn't have before.
erik_squires
15,872 posts
 
Well, routers usually are on 24/7, and the power requirements are minimal, so they don't usually draw enough, or cause enough DC offset to cause this.

Again, strongly suggest just turn off every single breaker except the one your conditioner is on.

 
erik_squires
15,872 posts
 
@lowrider

From your description though, it sounds like DC, not harmonics, and that's often caused by a switching power supply.  You didn't add a light dimmer either?? No new PC or router?

erik_squires
15,872 posts
 
Try turning off all other circuits in your home next time. :)

Did you add any new light bulbs, computers, or fancy LED lighting??
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