Volt drop problem

[danno99]

Hi, Im new here & unfortunately an electrician & not an electronics wizard.
I am hoping someone with greater electronics knowledge may be able to help me.
So, thanks in advance if you can!

I live in Italy & have a bad electrical supply authority. When I load my house up over 5KW the volt drop is as low as 165V instead of the supposed 220V
The authority are very slow responding & I need to cure a problem while waiting the months or years it takes them to deal effectively with their infrastructure.
I have a swimming pool heater which I believe is designed somewhat like an aircon unit. It has a compressor which cannot start at these lower voltages. I wonder if there is a relatively inexpensive way of making the unit work within the voltage ranges of 165V - 220V. The unit can demand upto 2.8kw although im not sure how much of that is merely the compressor & not really too sure what other parts are in trouble due to the lower voltage. I have got over a similar problem with my PC by buying a power supply capable of working within a range of 100V - 240V but I am now dealing with high wattages & am at a loss on the best option to take. Many thanks for any ideas.

 

[colin55]

1. Does the voltage drop in a linear way, as the wattage increases?
2. Do you have access to 2 phases?
3. Can you get a 50v transformer with 5 or 10 amp secondary?

 

[danno99]

Hi colin,
cheers for your quick reply, Im afraid I have extremely basic knowledge of electronics, but like to think im a good electrician
(-; So im hoping if someone gives me pretty laymen terms, I might just be able to answer. So assuming I have interpreted your queries correctly
1) The voltage drops in relation to the wattage, i.e more wattage less voltage. But does vary daily, i.e some days I can use 4KW with minimal volt drop. Possibly due to other users on my network from the substation.
2) I only have 220V single phase
3) I do not have such a transformer, but if it could cure my problem, I guess I would try & order 1
Thanks again

 

[colin55]

It's going to be a very difficult problem if the voltage rises and falls all the time.
Here is a voltage stabiliser circuit that will maintain 220v at 5 amps, even though the input may fall to 180v.

The only other thing you can do is manually add a 250w (50v x 5 amp) transformer so that the output adds to the incoming voltage. You can have a simple "sense circuit" that detects when the voltage reaches 200v and drops the transformer off the line.
If you put 2 x 250w transformers in parallel you can cater for 2kW.

 

[danno99]

Hi Colin, thanks for taking the time to try & help me out. I guess without simple drawings for me to follow your transformer & sensing circuit, I would probably end up getting it wrong. But maybe I will now take your ideas to someone that can put them to use, i.e a local electronics wizz kid (if I can find one that speaks English, as my Italian is nearly as bad as my electronics knowledge) All the best, Dan

 

[Diver300]

It may be very difficult indeed. As the voltage drops, you have to take more current to generate the same amount of power. You are already down to 165 V with 5 kW, and a transformer that increases the voltage will increase the current drawn from the supply. Your computer will take more current at 165 V than at 220 V but it's not big enough to make a difference.

Can you run the pool heater at night only? What other loads have you got?

 

[danno99]

Hi, I vaguely remember power divided by voltage = current. So I guess I lot of my equipment in the house will have a shortened life due to additional heat etc!
But getting back to my main problem, the heat pump for the pool, can only work when the pool pump is on to push water through it. The pool pump is 2KW on its own. So this makes the problem worse & pool pumps need to be on during the day. I did notice that some companies sell voltage stabilisers, but I dont know if they can allow such a low input voltage & presume they are quite expensive. Thanks for your post.