I want to make a circuit in which a bi color led changes color every time the circuit is switched on

bertus

Joined Apr 5, 2008
22,270
Hello,

How sure are you that after a main power failure the backup power is used and not a returning of the main power?

Bertus
 

Bernard

Joined Aug 7, 2008
5,784
Is there a difference in time when mains power dropps & gen. pichs up & the reverse? Seems that going from gen. to mains should be shorter, maybe somerhing like 10 sec?
Might be able to power ckt. with a charged cap. LEDs to come on only when power is restored.
 

tracecom

Joined Apr 16, 2010
3,944
I would expect that there is a discernible difference in the mains power and generator power, e.g., a slight difference in voltage, a slight difference in frequency, and almost certainly a difference in harmonic distortion. If this is correct, then a circuit could be designed that identified the power source based on that difference.
 

Thread Starter

fridodido

Joined Dec 27, 2014
18
Is there a difference in time when mains power dropps & gen. pichs up & the reverse? Seems that going from gen. to mains should be shorter, maybe somerhing like 10 sec?
Might be able to power ckt. with a charged cap. LEDs to come on only when power is restored.
Yes you are right but differentiating the source just on the basis of time variation wont be that accurate i guess
 

Thread Starter

fridodido

Joined Dec 27, 2014
18
I would expect that there is a discernible difference in the mains power and generator power, e.g., a slight difference in voltage, a slight difference in frequency, and almost certainly a difference in harmonic distortion. If this is correct, then a circuit could be designed that identified the power source based on that difference.
If that can be done, it would prove to be a fully automated solution to the problem but then i think i have to study the type of wave of each source which i have no idea how to do so. Also forgive me if im wrong as i dont have much knowledge about electronic circuitry

Thanks
 

MikeML

Joined Oct 2, 2009
5,444
I suspect that the real way of figuring out if the power is coming from the power company or from a generator will have to do with the frequency, voltage, harmonics, fluctuations, or other attributes of the AC waveform. In that case, a microprocessor based solution is likely to be required.

Oops, I just noticed that Tracecom already suggested this...
 

Thread Starter

fridodido

Joined Dec 27, 2014
18
I suspect that the real way of figuring out if the power is coming from the power company or from a generator will have to do with the frequency, voltage, harmonics, fluctuations, or other attributes of the AC waveform. In that case, a microprocessor based solution is likely to be required.

Oops, I just noticed that Tracecom already suggested this...
Yes if that can be made, nothing better then it, but for a bit simple though inaccurate solution we could have what GopherT has suggested (but only if your idea needs too much effort)

Y

You would need a Microcontroller with EEPROM. The ideas is that each time the Microcontroller turns on, it writes a flag it reads the current value of an EEPROM register and then changes that value (if it was "0" - backup, change to "1" - mains) and writes the new. Aloe to EEPROM. Then it lights the appropriate LED based on the 0 or 1.

This circuit assumes that EVERY time time the power goes out, the alternate power supply is used.

The circuit must be on all the time and you should check on a regular basis if it is in the proper state because it could happen that the same power supply comes on when power goes off.

Also, this circuit expects a zero power situation for both switch TO and FROM back-up power.
 

Bernard

Joined Aug 7, 2008
5,784
Just a straw mman to throw knives at: Also short on time. Assuming that there is a time difference , say that 15 sec.is shorter than mains to gen but longer than gen to mains, program SWs to 15 sec, digital comp will tell the dif. Got to goOutage Monitor. 00000.jpg
 

Bernard

Joined Aug 7, 2008
5,784
Short trip. If fridodido checks with gen. tech. might learn a lot about timing.
A short delay of 1 to 5 sec via R2, C2 should cover power spikes not taken care of by 5V charger. At outage, 555 triggers when C2 discharges to 1.5V causing pin 7 ( D1 anode ). When power comes back ,count is inhibited) Quick fix failed, what we need is an inverter from pin 3 to D1 anode so that 4060 count is enabled when pin 3, 555 is high. Count stops when power re established & is compared to programed count. A is SW selected Count. B is 4060 count. If A is less than B R14 LED comes on.
 

Thread Starter

fridodido

Joined Dec 27, 2014
18
Can there be some thing which i connect to the generator and then whenever the generator turns on the device transmits a wireless message to a led box at my apartment?

Sounds complicated but then it will not only solve my problem but also others living in the society

Is it possible? Maybe by some sort of radio waves or even through the internet?

Thanks
 

blocco a spirale

Joined Jun 18, 2008
1,546
How far is you apartment from the generator?

There are wireless current monitors that clip around an incoming power feed and transmit the value to a receiver with a display so that a property's power consumption can be monitored. Such a device could monitor the current at the output of the generator. I guess there may be IP based or Wi-Fi units out there. Have you considered pointing a web cam at the generator control panel?
 

MikeML

Joined Oct 2, 2009
5,444
Now you are understanding that your device needs two inputs, as I said way back in post #6. One input is that you have AC line voltage (but you don't know if it is coming from the power company or for a local generator). The other input is that the local generator is running, or not.

Can't you hear the local generator by putting your head out the window?
 

Thread Starter

fridodido

Joined Dec 27, 2014
18
Now you are understanding that your device needs two inputs, as I said way back in post #6. One input is that you have AC line voltage (but you don't know if it is coming from the power company or for a local generator). The other input is that the local generator is running, or not.

Can't you hear the local generator by putting your head out the window?
I know Mike you are right but as the generator is almost a mile away from my apartment i had to rule out that idea. But if there can be some sort of wireless link between a transmitter(at gen room) and the indicator(at apartment) it would solve the problem as drawing a mile long wire seems quite impractical
 

eetech00

Joined Jun 8, 2013
3,859
I know Mike you are right but as the generator is almost a mile away from my apartment i had to rule out that idea. But if there can be some sort of wireless link between a transmitter(at gen room) and the indicator(at apartment) it would solve the problem as drawing a mile long wire seems quite impractical
That depends on how sophisticated the generator is. The one at our facility can send snmp, email, or text alerts. If yours supported snmp, it could send any of these alerts via an snmp management station.

Do you know if the generator produces sine wave output?

eT
 
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