mains supply or generator supply?

[ADWSystems]

If the OP is in an apartment and has no control over the supply, be it from the utility or generator, what good does knowing the supply source do? Suppose the OP wants to unplug some susceptible consumer devices if the generator is in use, because (for argument's sake) the gen puts out damaging square waves. By the time the magic monitor has detected 'generator running' any damage is probably already done

No argument from me on that. On the other hand, the output of the magic monitor could be setup to "unplug" (ie., relay or contactor to disconnect) the susceptible device from the outlet. No we're getting fancy...

 

[jpanhalt]

It has also been assumed that the manager/owner would let the OP have access to the generator room to put the "baby monitor." That privilege is definitely not assured.

We still don't know why the OP feels he needs to do this.

According to the Indian standards, frequency of the grid must be held between 49.5 to 50.2 Hz

Source: https://www.electro-tech-online.com/custompdfs/2013/09/Indian_Electricity_Grid_Code.pdf

All Users, SEB,, SLDCs , RLDCs, and NLDC shall take all
possible measures to ensure that the grid frequency always
remains within the 49.5 –50.2 Hz band.

I read something this morning that that range was narrowed in September, 2012. Monitoring frequency may still be a viable alternative.

John

 

[Nigel Goodwin]

According to the Indian standards, frequency of the grid must be held between 49.5 to 50.2 Hz

No disrespect to our Indian members, but I'm not terribly confident about India maintaining accurate frequency controls.

 

[jpanhalt]

There is actually a great deal on the Internet about grid problems in India due in part to frequency stability problems. That is one reason the standard was tightened last September.

Just out of interest, while researching the question for India, I came across this site for the UK:

**broken link removed**

I could not find a similar site for India. The UK standard is +/- 0.5 Hz, which I believe is pretty close to the newest Indian standard. The UK is usually maintained +/-0.2 Hz according to the link just provided.

John

 

[samovar]

If you plug this magic thing we're helping design into an outlet with no load on it, there would be no voltage drop/change. Therefore we wouldn't have to worry about this.

Would be the case if all outlets were connected to generator in "star" configuration. But it's always some common wiring. Imagine you're running a 3 ton A/C with 0.6 power factor. The highest current will be when your voltage is around 60 volts. Current might be 30 amps. If common wiring (between the appartment and transformer) has 200mohm resistance, it'll be 6 volts of a drop. You'll see 54 volts instead of 60 volts. That's quite a distortion. If high current is present when voltage is close to zero, it'll be even worse distortion. Something you can easily mistake for a "bad" generator.

 

[alec_t]

Imagine you're running a 3 ton A/C with 0.6 power factor.

I'm imagining........ There's a guy in a tiny apartment on the third floor of a building in India. Most of the apartment is occupied by this 3 ton monster...........

 

[samovar]

I'm imagining........ There's a guy in a tiny apartment on the third floor of a building in India. Most of the apartment is occupied by this 3 ton monster...........

Haha!

Then imagine that when appartment was built they wanted to save money on wires and the whole appartment building is fed by a long #6 wire, which has 2ohm resistance, and when people start using power, the sine wave transforms into something totally unrecognizable and sometimes power goes off completely