Power failure detection device

[bankruatsteve]

So, you just want to know external power failure and if that doesn't happen but your device does then you will assume internal problem, yah? And, the internal problem would then be an intermittent sub-second power out. OK. In any case, if the issue is the power outage to the device, you should have a UPS. Otherwise, I don't get it. Good luck.

[JesseFrank]

So, you just want to know external power failure and if that doesn't happen but your device does then you will assume internal problem, yah? And, the internal problem would then be an intermittent sub-second power out. OK. In any case, if the issue is the power outage to the device, you should have a UPS. Otherwise, I don't get it. Good luck.

I know I need a UPS to protect my device, but that is not the subject of this thread, since a UPS will tell me there is a power outage but it won't tell me if the problem lay with the PEA or is a bad connection somewhere in my house wiring.

If ALL appliances in the house would go off at the same time, I would be sure that it is a PEA issue, but since only the appliances in the part of the house that is the closest to the CBB are affected it is a guess what causes it.

If it should be determined that the power cut isn't caused by the PEA, then I think it is important that I get a sparky in as soon as possible, but I'm not gonna waste money on a sparky if there is no need for.

[RichCor]

[...]

The homemade devices I have on the other appliances must cost next to nothing to build, since the electrician didn't even charge me for them. It's just a small plastic box with an led glued into it and a plastic pressure switch to reset it.

Too bad they are designed for a 12V DC system otherwise I would remove one and install it on the breaker.

Probably possible to connect a common 240vac/12vdc power adapter. The only issue would be if power adapter is providing residual carry-over current (from a capacitor) and your 12v device not drawing down the current quickly enough (thus allowing short transient power loss issue to be masked).

You could test this by plugging the newly wired kit into a switched power extension cord and quickly toggling the on/off switch to see what power-off gaps it will detect.

And, as Crossy stated, if you open one of your boxes the circuit design of your current power-fail detector could probably easily be copied so you could have several working at the same time. Just need the right power supply adapter.

[JesseFrank]

[...]

The homemade devices I have on the other appliances must cost next to nothing to build, since the electrician didn't even charge me for them. It's just a small plastic box with an led glued into it and a plastic pressure switch to reset it.

Too bad they are designed for a 12V DC system otherwise I would remove one and install it on the breaker.

Probably possible to connect a common 240vac/12vdc power adapter. The only issue would be if power adapter is providing residual carry-over current (from a capacitor) and your 12v device not drawing down the current quickly enough (thus allowing short transient power loss issue to be masked).

You could test this by plugging the newly wired kit into a switched power extension cord and quickly toggling the on/off switch to see what power-off gaps it will detect.

And, as Crossy stated, if you open one of your boxes the circuit design of your current power-fail detector could probably easily be copied so you could have several working at the same time. Just need the right power supply adapter.

Indeed the power adapter is slowing down the effect. The devices are actually alarm sensors which are powered by an adapter and installed outside, and the power will have to go off for a few seconds before they lose power.

Do you know the answer if I can easily replace the wireless module in the Step i501, which I posted in #20, with such a small pressure switch since that device works on 220V and does the same as the 12V DC devices.

Edit : forget about the last question, because i notice that the step has also a few capacitors inside, so it probably will not switch fast enough anyway.

Edited August 21, 2014 by JesseFrank

[RichCor]

Indeed the power adapter is slowing down the effect. The devices are actually alarm sensors which are powered by an adapter and installed outside, and the power will have to go off for a few seconds before they lose power.

Do you know the answer if I can easily replace the wireless module in the Step i501, which I posted in #20, with such a small pressure switch since that device works on 220V and does the same as the 12V DC devices.

If the wireless module is a 'dry' contact closure (very little current, or short to ground occurring) then the answer is yes.

The the wireless module is a 'wet' contact closure (closes or opens a circuit that passes a current), then the replacement switch would need to be rated at the current being passed.

As there are different type of 'switches', you'd need to discover if it was 'normally open', 'normally closed' and duplicate that action.

[JesseFrank]

OK the simplest answer:-

Untitled-1.jpg

How it works:-

Mains power goes to J1,

Lamp 1 lights to indicate mains present, Lamp 2 is off.

Press S1

Relay K1 pulls in, Lamp 2 lights.

Release S1

K1 remains energised by its NO contact (9 and 5)

If the mains fails K1 will drop out.

When mains returns we are back to the start, Lamp 1 lights to indicate mains present, Lamp 2 is off.

Whilst it will work, there are a number of issues:-

The voltage at which the relay drops out is indeterminate, a couple of tests on ones I have with 220V AC coils shows that once energised they stay pulled in even when the supply goes down to 120V

The time of an outage required to drop the relay is also indeterminate, I currently have no means to measure this, but 50ms would not be unreasonable.

Crossy, what is 13 and 14 in the diagram ?

The wireless device I have has a Songle srd-12vdc-sl-c , can I use this one instead of the Omron MY2N ?

[JesseFrank]

Indeed the power adapter is slowing down the effect. The devices are actually alarm sensors which are powered by an adapter and installed outside, and the power will have to go off for a few seconds before they lose power.

Do you know the answer if I can easily replace the wireless module in the Step i501, which I posted in #20, with such a small pressure switch since that device works on 220V and does the same as the 12V DC devices.

If the wireless module is a 'dry' contact closure (very little current, or short to ground occurring) then the answer is yes.

The the wireless module is a 'wet' contact closure (closes or opens a circuit that passes a current), then the replacement switch would need to be rated at the current being passed.

As there are different type of 'switches', you'd need to discover if it was 'normally open', 'normally closed' and duplicate that action.

How I know if I have a wet or dry contact closure ?

[RichCor]

How I know if I have a wet or dry contact closure ?

Depending on the circuit, if safe and prudent to measure, this could be done using a DigitalMultiMeter (DMM).

Generally, we want to know:

1. if the circuit in question (the wires going to the wireless module) carry current, what type, and how much.

2. how the wireless module functions in this circuit, what does it do in a normal state, what does it do in an alternate state (stays switched, momentary on, other?), possibly even the length of each state.

Let's say [black probe to gnd] the red probe of a DMM (measuring the two wire leads entering the wireless controller) indicated 12vdc on one input lead, and normally 0vdc (or no voltage) and then 12vdc only when the remote was pressed on the other input lead.

This would indicate the wireless module is acting as a contact switch, normally held OPEN (no thru contact), MOMENTARY closure (has thru contact), then returns to OPEN.

The wireless module in this hypothetical case could be replaced with a momentary switch with a rating of 12-14vdc and the proper ampere rating of the circuit or the max output of the power supply.

edit: I had tried using google to get a good description of a 'Wet' vs 'Dry' contact closure but that only proved that most people who post to the Internet on Electrical or Electronic nomenclature are very, very stupid or just not qualified to post answers. Anyway, just be careful as a 'Circuit', 'Switch' or 'Relay' might be low-voltage isolated signal bearing or high-voltage load bearing.

Edited August 21, 2014 by RichCor

[Forkinhades]

You are not going to find a power monitor / analyser that will give meaningful results for much less than USD 1000, although those units shown by richcor actually look pretty useful at 500.

Back home one would go and hire one, here, I've not seen test equipment hire although it's doubtless available.

To be honest, if you are seeing short dips the chances are strong it's just dirty switching of the supply network, get a UPS for the computer. Many UPSs have simple monitor functions built in so could be usable if plugged into your outside outlet if you are that worried.

I have UPS and a NAS box, monitors the systems very nicely, even with pc equipment off. (NAS box on though)

[Daffy D]

As I understand it the OP wants to know whether the power out is from the power company or some fault within the house.

When we get a power out first thing I do is check the neighbors lights

Why not connect a digital clock to the supply as it comes into the Consumer unit before any internal wiring.

The clock does not have to be visible all the time just used for checking after a power glitch.

Just a bit extra info which might be useful to someone. Some time ago the power went of in the house, checked the neighbors and they were OK so checked my consumer unit and that had live feed so could not figure why nothing worked.

Eventually discovered that the Negative/Neutral connection in the consumer unit had been arcing due to bad connection and so there was no return feed so nothing worked.

Connected all the Neutral wires back together and all was fine.

[JesseFrank]

As I understand it the OP wants to know whether the power out is from the power company or some fault within the house.

When we get a power out first thing I do is check the neighbors lights

Finally someone who can read an OP, or maybe one who cares to read, however with a glitch of a fractional second it's a problem to check if the neighbors lights went out at the same time.

Why not connect a digital clock to the supply as it comes into the Consumer unit before any internal wiring.

The clock does not have to be visible all the time just used for checking after a power glitch.

Just a bit extra info which might be useful to someone. Some time ago the power went of in the house, checked the neighbors and they were OK so checked my consumer unit and that had live feed so could not figure why nothing worked.

Eventually discovered that the Negative/Neutral connection in the consumer unit had been arcing due to bad connection and so there was no return feed so nothing worked.

Connected all the Neutral wires back together and all was fine.

I was already playing with the idea of a AC powered digital clock, as Richcor suggested, but I'm not sure if I can find one at a reasonable price. It doesn't make much sense to pay 2000 Baht for a device you need only once. So any suggestions welcome.

[jawed]

Hii Jesse where are u from

Sent from my HTC Vision using Thaivisa Connect Thailand mobile app

[IMHO]

Just run a couple of wires in parallel from your meter, and sit your microwave at the bottom of the mains post for a day or two - set the clock of of course

[wayned]

I actually have one of those cheap analog voltmeters sitting on my desk. I shortened the leads and put a standard electric plug on the other end and plugged it in. I can see what's happening when it happens, but it does not record the event. Everyday my power was switching between 140vac and 220vac, at regular intervals, I could watch the event, but not record it, and it would never happen when PEA was there. My village was on a single phase transformer and they finally came and installed a three phase transformer, additional wiring. and redistributed the power in the village. The problem went away. I suspect that the culprit was/is the gravel yard about 1 kilometer away.

Even with the new distribution, we still get momentary outages every morning, probably switching, and the power is off frequently, the last time yesterday afternoon for about 4 hours, a clear bright day. The only way that you will "record" the event to be able to show anyone is to use a recorder as I said earlier, but they are not cheap and I don't know where you can rent one.