I have a unique project I need to complete. Around this time of year the power grid around where I live get's hammered from there being to many people on the grid and secondly from all the A/C units coming on at once it gets overloaded quick. So this usually results in 3 - 4 power outages a week. There usually not long, more of an on - off thing. For example today, power went out, you hear a transformer on a pole blow and then the secondary transformer kicks in and power is restored. Exploding transformers are a common sound around here.

Any ways I have a few servers that I need to have as little down time as possible. Now I know a UPS would be the right thing to do but at the moment I don't have the money for a large enough one so I need to make due with what I can make. I need something that will switch when the power goes off and then when power is restored wait 5 min and restore power to the servers booting them back up OR turning them back on via the power switch pins on the motherboard.

The reason I need it to wait 5 min or so is because around here we also get times where the power will go on-off-on-off-on-off-brown out-off-on within 30 seconds and will kill or damage any sort of computer you have. (already gone though 4 modems).

I've had a few ideas but none we're to complete maybe someone here has a few.

 

Just to understand: If you had a timer that would give a 5 minute countdown whenever it powered up, and then trips a switch to turn on everything else, that would do it?

Can you estimate the current draw that needs to be switched?

 

That on-off-on-off is a pattern here that means the power system is trying to reset, but there is a hard fault on the line. When I see that pattern, I know I will be phoning the power company to send a truck out. Point is, it isn't a strange thing. It's an auto-reset attempt.

I once made a circuit with a well filtered DC voltage reference compared to a barely filtered full wave rectification of the line voltage. Any missing pulses or brown out and the safety would switch in less than 17 milliseconds. That was my cure. Just shut down the equipment before the compressors stall and go into locked rotor current. Might not work for you, but It's an idea. You can find a missing pulse with an analog method.

 

Tell the power company that you are losing business, that puts them in liability and they will hasten to put in a recorder or other fix. It worked for me.

 

The power company didn't need a recorder to tell a whole substation was down.

Actually, my first reaction was, "Ha ha ha!"
I tried that once. The recorder showed a hundred drops to 58% of rated voltage in a week. They told me it was nothing to worry about...well, nothing for them to worry about. I was glad to leave that job!

 

Servers? and you don't have money for back up power?

Not a good business plan. Sorry to be so negative, but the first thing a prospective business owner should learn is 'what are the costs of doing business?' Lack of proper equipment does not earn my pity. Business operation is important(if you want to make money and stay in business), so doing less than the minimum required will almost always result in a loss, and then the 'going out of business sale'.

GET THE UPS YOU NEED, perhaps you need a small business loan.

 

Just to understand: If you had a timer that would give a 5 minute countdown whenever it powered up, and then trips a switch to turn on everything else, that would do it?

Can you estimate the current draw that needs to be switched?

Yes that would work. But the timer would need to be set to turn on once the power came back on after it shut off.

Not to sure what you mean about the current draw. On the motherboard of the computer once power is supplied to the motherboard all you need to do is jump two pins that usually connect to a momentary switch on the front of the case to turn on the computer. So what the timer would do is after 5 min jump these pins momentarily to switch on the computer.

The tricky part for myself is figuring out how I'm going to first detect that the power is off and then set the timer to come on when the power is restored. Keep in mind I have the computer set to stay off when the power is restored.

That on-off-on-off is a pattern here that means the power system is trying to reset, but there is a hard fault on the line. When I see that pattern, I know I will be phoning the power company to send a truck out. Point is, it isn't a strange thing. It's an auto-reset attempt.

I've called the power company but to my luck there all on strike..... sigh.

Servers? and you don't have money for back up power?

Not a good business plan. Sorry to be so negative, but the first thing a prospective business owner should learn is 'what are the costs of doing business?' Lack of proper equipment does not earn my pity. Business operation is important(if you want to make money and stay in business), so doing less than the minimum required will almost always result in a loss, and then the 'going out of business sale'.

GET THE UPS YOU NEED, perhaps you need a small business loan.

I'm mining bitcoin. I need them to stay on 24/7 for optimal payout. I'm trying to pay off the computer / server I built to mine with. Once I get it paid off then I will buy a UPS, until then I cant afford it.

 

I'm mining bitcoin. I need them to stay on 24/7 for optimal payout. I'm trying to pay off the computer / server I built to mine with. Once I get it paid off then I will buy a UPS, until then I cant afford it.

Sounds like you didn't plan this out very well. You said "Around this time of year the power grid around where I live get's hammered from there being to many people on the grid". Only now does it occur to you that this is a problem?

If it is important to you - get a loan. Get a partner with a UPS and split some profits from those magic 'bitcoins'. Sell something and buy a UPS. Settle for something less than 'optimal payout' You have lots of options.