Smart AC Power Circuit Breaker with Web Control?

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Ray
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Smart AC Power Circuit Breaker with Web Control?

Post by Ray »

We had a car that ran into a utility pole late yesterday and took out the AC power. This has happened several times before and is can be handled remotely with the station controller. This time however, the surge tripped a 115 VAC circuit breaker in the control room that powers the computer UPSs. It had to be reset manually. We were on backup audio for almost an hour. All the other breakers were fine including the 220 VAC Tx.

Has anyone used one of the new "smart" circuit breakers that are web enabled that we could reset remotely? It would be nice to have something that would substitute directly for the current breaker and not install a new panel box. The old panel box is about 40 years old.

Ray

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Re: Smart AC Power Circuit Breaker with Web Control?

Post by NECRAT »

Ray wrote:
Sat Jan 04, 2020 7:32 am
The old panel box is about 40 years old.
I would never want a circuit breaker that I can't reset in person. If something causes a trip, you're not sure, hit "reset", and it comes back, you could be looking at replacing the panel with the rest of the building that burned down. For the nuisance for an occasional trip, I'd leave well enough alone, however*

You mentioned the panel is 40 years old. Circuit breakers can "weaken" over time, and not run at their full capacity. I've seen it more than once. It may be worthwhile looking into having a licensed electrician replace the breaker in the panel.
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Re: Smart AC Power Circuit Breaker with Web Control?

Post by DaveSt »

NECRAT wrote:
Sat Jan 04, 2020 2:33 pm
Ray wrote:
Sat Jan 04, 2020 7:32 am
The old panel box is about 40 years old.
I would never want a circuit breaker that I can't reset in person. If something causes a trip, you're not sure, hit "reset", and it comes back, you could be looking at replacing the panel with the rest of the building that burned down. For the nuisance for an occasional trip, I'd leave well enough alone, however*

You mentioned the panel is 40 years old. Circuit breakers can "weaken" over time, and not run at their full capacity. I've seen it more than once. It may be worthwhile looking into having a licensed electrician replace the breaker in the panel.
Same here. It is certainly worth changing the circuit breakers and make sure they have the correct tripping characteristic for the load.

As NECRAT rightly says, you want to be within sight of the load when resetting a breaker to see where the smoke comes from.

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Re: Smart AC Power Circuit Breaker with Web Control?

Post by jthorusen »

Be advised:

If you can reset it, your friendly world wide located hacker can turn it off.

I agree that a purely manual breaker is the way to go.

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Re: Smart AC Power Circuit Breaker with Web Control?

Post by kcbooboo »

Reminds me of the photo in RadioWorld magazine's Workbench column that showed a Continental Electronics FM TX circuit breaker being pulled up/on through a rather large externally-mounted solenoid? Seemed like a clever idea but I too agree that you really want to be present when restoring power.

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Re: Smart AC Power Circuit Breaker with Web Control?

Post by kkiddkkidd »

One of my current clients (elderly engineer/tinkererer himself) has a washing machine agitator attached to a breaker in the main box that powered his old Collins (now stby) TX. He worked for days to get it attached and rigged with limit switches. If the power blinked several times rapidly (happened weekly on the mountain before the lines were improved), it would trip the tx panel breaker. He could control the agitator with the RC and not have to drive up to the TX just to reset the breaker.

Many years ago, I told him that they had just invented this thing called a "fused disconnect" and he had no idea what I was talking about or why he would need one.

kcbooboo wrote:
Tue Jan 07, 2020 5:30 am
Reminds me of the photo in RadioWorld magazine's Workbench column that showed a Continental Electronics FM TX circuit breaker being pulled up/on through a rather large externally-mounted solenoid? Seemed like a clever idea but I too agree that you really want to be present when restoring power.

Bob M.
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Re: Smart AC Power Circuit Breaker with Web Control?

Post by kkiddkkidd »

I concur... I have found that phantom breaker trips typically have a very real cause. Weak breaker, corroded breaker lug, overloaded circuit, borderline rated breaker, bad wiring, looming equipment fault, etc.

One of my FM TX sites developed an intermittent breaker trip on a breaker feeding the rack. The owner could typically get there before myself and for a while just reset the breaker without letting me know. At some point, he noted that he occasionally heard an odd buzz from the plywood wall and HVAC duct near the breaker panel when he reset the breaker AND occasionally it would trip a 2nd time. I freaked. I moved the rack plugs to a different circuit and checked the troublesome circuit. Totally disconnected on both ends, Instead of infinite resistance, the hot wire measured several hundred ohms to ground and the meta duct. They had plenty of circuits and outlets so I just pulled the breaker, outlets and cut the wire off at the boxes. I suspect that a mounting screw for the HVAC ducting had penetrated the romex inside the wall and was slowly deteriorating.

Although not exactly a fault, I was called to a sometimes client (now defunct) to replace a bad AC panel TX breaker (weird SS 10kw offshore FM box) that tripped every few days. On arrival I found that the breaker was correctly sized for the licensed TPO but thinking that it was weak, replaced it with a new one. Turned the TX back on and it now tripped the breaker after a few minutes. I paid more attention to the TX for the few minutes that the breaker would hold and instead of running it's licensed 5500w TPO, it was running WFO at about 11kw. And apparently had been for months. i reset the TX to licensed TPO and the current draw was well within the installed breaker & wiring. I doubt that anyone with the station could have figured out how to navigate the convoluted menus to change the TX power and it never happened again that know of.

Later,
jthorusen wrote:
Tue Jan 07, 2020 12:16 am
Be advised:

If you can reset it, your friendly world wide located hacker can turn it off.

I agree that a purely manual breaker is the way to go.

Regards,
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Bill DeFelice
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Re: Smart AC Power Circuit Breaker with Web Control?

Post by Bill DeFelice »

Likely a much safer bet would be to get something along the lines of a Eaton ATS rack PDU AC transfer switch and connect the inputs to two different 120vac circuits. Then you can connect your UPS to the output of it, so the UPS will only be used if both AC circuits failed. It's probable that if two different AC circuits failed, especially if they were on different phases of the incoming service, you'd probably be without service to operate the transmitter anyways.
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Re: Smart AC Power Circuit Breaker with Web Control?

Post by NECRAT »

kcbooboo wrote:
Tue Jan 07, 2020 5:30 am
Reminds me of the photo in RadioWorld magazine's Workbench column that showed a Continental Electronics FM TX circuit breaker being pulled up/on through a rather large externally-mounted solenoid? Seemed like a clever idea but I too agree that you really want to be present when restoring power.

Bob M.
I saw this modification in Central New York.

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Re: Smart AC Power Circuit Breaker with Web Control?

Post by jthorusen »

For Necrat regarding the Continental:

I can see one possible use for such a setup. On a Collins 831G (same transmitter, more or less) we once had a failure where there was such a hard short on the 208 line that one of our techs got his arm burned by the fire that came out of the front of the breaker. All subsequent breaker closures were made with a towel covering the hand and arm. The solenoid would have come in handy. :D

All kidding aside, I think it would be better to note the flames than close the breaker repeatedly by remote control, oblivious to the real problem.

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Re: Smart AC Power Circuit Breaker with Web Control?

Post by spareparts »

ABB (and I'm sure others) make motor operated circuit breakers.

The question is what is the breaker tripping in the first place?

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Re: Smart AC Power Circuit Breaker with Web Control?

Post by ChuckG »

Some of those continentals were known for nuisance plate breaker trips with no discernable cause. If you are looking at 4 hours one way to *click* and turn right back around...the solenoid makes a lot of sense.
If it trips twice, or the service breaker goes.... you get in the truck.
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Re: Smart AC Power Circuit Breaker with Web Control?

Post by kcbooboo »

"Some of those continentals were known for nuisance plate breaker trips with no discernable cause."

I worked on one such unit that was tripping the breaker every few days due to a phase loss internal to the TX. After replacing a couple of SCR modules, the SCR driver boards in the card cage, one of the phase-sense xfmrs behind the card cage, and the plate breaker, the issue was finally traced to some 3PDT 28VDC plug-in relays mounted above the plate xfmr. When the relays were swapped around, other more serious problems cropped up. Tapping the offending relay would cause the plate breaker to trip. Eventually through careful observation we noticed that one of the relay's flexible wires going from the moving contacts to the base terminal had never been soldered by the relay mfgr. It was wrapped around the lug and that was it. We took the cover off the relay, soldered the terminal, put it back, and it's been working fine ever since.

The relay was applying 3-phase power to the phase-sense xfmrs behind the card cage when PLATE ON was pressed. The slight vibration from the big fan at the top of the cabinet was causing the contact to be intermittent enough that the power controller briefly lost one phase. The subsequent overload would trip the plate breaker. The power controller will run fine with just one phase or all three, but not two.

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Re: Smart AC Power Circuit Breaker with Web Control?

Post by NECRAT »

spareparts wrote:
Tue Jan 07, 2020 8:17 pm
ABB (and I'm sure others) make motor operated circuit breakers.
Motor Operator Breakers are typically only found in machine control logic systems, where breakers are also tied to a shunt trip, and used as a method to reset. They are never found in life or property safety panels.
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Re: Smart AC Power Circuit Breaker with Web Control?

Post by radiowave911 »

All I can really add is to echo that blindly resetting a breaker without knowing why it tripped in the first place is a bad idea. Circuit breakers in a panel are there for safety. If one trips, then there was something not right with the power going through the breaker. As was mentioned, it could also have gotten weak. Having a licensed electrician inspect the panel and breakers is probably not a bad idea. Replacing the breaker is likewise probably not a bad idea.

If you can get to it via the internet, so can any one else. These 'Internet Of Things' devices sound great and very much talk up how you can easily control your lights and appliances and see who is at your door from your hotel room halfway around the world, etc. etc. The problem is, the design of many of these devices treats network security as an afterthought. From such ill-advised practices as using insecure communication channels, weak encryption (when it is present), limiting password length and complexity, running services on the device that are not needed but came bundled with the operating system they bought for the device, poor patch management (if it even exists), etc. I could go on and on, and I have not even started on how these devices could be used as a launchpad for an attack on other networks and systems within the facilities they are installed in.

None of this IoT stuff should ever, in my opinion, be anywhere near something critical - whether life safety or business mission critical. If it is important, it should be protected. Sacrificing protection for ease of use is an exeptionally bad idea.
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