Calling All Electricians - ID this mystery box

[rmaynard 15,427]

Yesterday morning we awoke to an electrical problem in our house. Some lights worked, some didn't. No water pump, oven, dryer etc., so there was no 240 volts.  So I started investigating. Meter read 120v at some outlets, 80v at others. LED's and CFL's flickered.  I took the cover of the electrical panel. I flipped the double breaker for the water pump to off and all the outlets that read 80v went off, as did all the lights that were flickering. I checked the incoming feeder line and found that one leg read 120V and the other read zero. Ah ha! 

 

So I determined that one phase of my incoming power from the power company was non-existent. I called the power company, they sent out a team, and discovered that one leg of the feeder to my house had burned out underneath my asphalt driveway. Not wanting them to dig up my driveway to make the repairs, I asked that they run a whole new wire since the old one had been there 40 years. They agreed but said it could be a couple of weeks since they had sent a large crew to North Carolina. Anyway, they said that they could restore my 240V with a temporary fix. This is what they installed.

 

 

I call it the mystery box.

 

In all my years, I have never seen one of these. Somehow it takes the one good 120V line and redirects it to a box on the hand truck and it comes back out as two separate 120V circuits to simulate the two 120V leads that were coming into my panel.

 

So my questions is HOW DO THEY DO THAT?

[ebinmaine 67,266]

Bob, I don't have the faintest idea but I'm curious to see what the answer is.

 

One question I have.

Do you now have half of the available previous amperage?

 

[buckrancher 2,679]

not sure what's in the upper box but the bottom one looks like a buck transformer

[rmaynard 15,427]

Eric, in answer to your question, I don't know. The "kids" that installed it didn't know how it worked, but when I asked the question about amperage, they said it would be the same. I doubt it. If that were the case, why run two wires in the first place. Just run one and a magic box.

 

Brian, what's a buck transformer?

 

 

 

 

Edited September 18, 2018 by rmaynard

[JPWH 6,032]

Probably a step up down transformer and a buck boost transformer.

[ebinmaine 67,266]

1 minute ago, rmaynard said:

when I asked the question about amperage, they said it would be the same.

Let's just put this first. I am no electrician.

 

 

But I just don't see how you can split voltage and still have it be the same amperage.

 

I'm looking forward to the actual answer on this one...

[rmaynard 15,427]

1 minute ago, JPWH said:

Probably a step up down transformer and a buck boost transformer.

 

Could you further enlighten us?

[rmaynard 15,427]

Here's a pic of the front. 

 

[WHNJ701 4,165]

probably shouldn't touch it

[WHX?? 48,763]

Hank nailed it but this explains it way better than I can. https://en.wikipedia.org/wiki/Buck–boost_transformer The one box may have capacitors in it to help shift the phase. These are sometimes used  in larger commercial HVAC applications.  @squonk might be able to elaborate more.

27 minutes ago, ebinmaine said:

split voltage and still have it be the same amperage

The voltage isn't split.....  the phase is shifted to 180 deg from the other one giving you back 240 volts. The amount of current of the whole affair can handle  is limited by the size of the in/out cables and the rating of the mystery boxes.

[WHX?? 48,763]

17 minutes ago, jabelman said:

probably shouldn't touch it

Lol ...it's all grounded and quite safe.

[WHX?? 48,763]

1 hour ago, rmaynard said:

Just run one and a magic box.

All power generation and  transmission systems, except for small portables,  revolves around having three phases that are manipulated by transformers, witchcraft and PFM. The power that gets sent to your house and small businesses is  two phase power derived from said transformers, witchcraft and PFM. Ok they are called really called  substations.   This is required  order to avoid cables the size of your leg running to your house. Mystery boxes also produce heat which means wasting power that could be uses to light your bulb. Hence you don't get to keep the mystery box but you do get to pay for the eddy current losses!

This concludes electrics 101... next lesson will be on the difference between delta and wye wired mystery boxes, I want you all to read chapter 5 of your textbooks.  Ther will be a quiz on Friday!

Edited September 18, 2018 by WHX20

[rmaynard 15,427]

2 minutes ago, WHX20 said:

Hence you don't get to keep the mystery box but you do get to pay for the eddy current losses!

Since the mystery box is on the power company side of my meter, aren't they paying for the eddy current losses? 

[WHX?? 48,763]

It all depends on how that adapter plate the meter plugs into is wired. Go pull the meter off and take a pic and we'll see.... second thought maybe not.....

[squonk 41,020]

30 minutes ago, WHX20 said:

Hank nailed it but this explains it way better than I can. https://en.wikipedia.org/wiki/Buck–boost_transformer The one box may have capacitors in it to help shift the phase. These are sometimes used  in larger commercial HVAC applications.  @squonk might be able to elaborate more.

The voltage isn't split.....  the phase is shifted to 180 deg from the other one giving you back 240 volts. The amount of current of the whole affair can handle  is limited by the size of the in/out cables and the rating of the mystery boxes.

Jim I'm thinking your thinking of a phase converter. Running 3 phase equip in a building that only has single phase feed. I'm thinking that box is a transformer converting 120 to 240 and along for the ride are some caps and heat sinks in the boxes to smooth out the power. @Sparky prolly knows for sure. 

[Machineguy 877]

Would this box allow a DeLorean to travel through time? I’m really having a tough time locating a flux-capacitor. 

Edited September 18, 2018 by Machineguy

[squonk 41,020]

1 hour ago, rmaynard said:

Here's a pic of the front. 

 

I like it! There a holder for either a BBO tank to start a quick fire or a reefer tank to put it out! 

 

Bob, looks like some nice dump trailer wheels and tires on there! 

Edited September 18, 2018 by squonk

[WHX?? 48,763]

Somethin  like that Mike, I forgot most of my power wiring crap since I was demoted to a lowly residential HVAC tech!

[WHX?? 48,763]

Aint that just like you clowns ....Poor Bob is suffering from Florence's beating and you wise guys are cracking jokes

 

This is where you hang the brat tongs on Bob.

Edited September 18, 2018 by WHX20

["D"- Man 827]

I work for an Electronic company, however I am a meter reader.  That being said, I have occasion on more than one of these boxes hooked up to a residents house.  They have to be receiving the power from the line side {hence prior to the meeting, } so the customer does not get charged for the "lost Eddy currents" as it is only metered kwh's that are billed.  The device has to have the 120 v AC transformered into 240 v AC w/ground or neutral, so that this provides an equal 2x 120 v AC  feeds.  Now it should be obvious that this will draw at least twice the current from the good leg, to provide the same power with the 2 legs.  

P.S. is the quiz open book?

[Racinbob 11,040]

Never seen anything like it after 45 years in the industry but I think Mike and Jim are on it. Transformers work in both directions. Caps might be used to correct the power factor but I don't see why that would be needed in your residential application. I seriously doubt that you have the full capacity of your service but that shouldn't be a problem. 

 

A buck/boost transformer is often used to correct a hi or low voltage situation. They can be much smaller than a transformer needed to power the given service rating. The best way I explain it is that it only carries the current needed based on the voltage it needs to correct. They wouldn't be boosting 120 to 240 with one though. Along with other limitations that would only give you one leg with 220 on it. 

 

For the short term Bob, I don't think you'll even notice any difference. 

[pfrederi 17,663]

Its magic to me ...just like a magneto Have read about them numerous times bottom line black magic....

[Machineguy 877]

All joking aside, electrical theory is fascinating to me. Electricity is powerful and amazing and the science behind it is really cool stuff. I should learn more about it. 

[953 nut 55,065]

The magic box is simply a two to one step-up center tapped transformer. They pulled your meter and installed a plug and play device that runs the 120 volts from the incoming line to the primary wingdings. The secondary part of the transformer has twice as many winding and the output will be split by the grounded center tap. The 240 volt AC (two 120 volt lines of instantaneous opposite polarity) will be returned to the plug in device and feed your panel. It operates on the same principal as the transformer on the power pole. 

Amperage depends on how much power you are using. In terms of plumbing the voltage is Pressure and amperage is Flow rate (GPM).

[squonk 41,020]

LETS ALL GO TO BOB'S HOUSE AND TURN EVERYTHING ON!!! WHO'S GOT A BIG COMPRESSOR THEY CAN BRING!!!!!! 

 

Just kidding Bob stay safe!