Electrical Bits But Nothing Is Simple!

[nobber9999]

Hi,

I live approx 30 km outside of Korat and am in dire need of a AVR (auto voltage regulator) due to the ups and downs from the power Company. My main cause of problems are my AC units and water pumps eat a lot of juice on startup and the other is just the quality of power that arrives on my doorstep. Using rough calculations I would need a AVR with a power rating of 15 KVA which would cover max only any one time but may not be enough to cover say 2 or 3 pumps kicking in at the same time. My swimming pool pump has some effect but it only has a rating of 1.1 KW but that is running for long periods rather than clicking in and out. Having read posted articles about this I feel the AVR is the solution but my problem is where the hel_l do you buy one of these things??? I have searched high and low in all the obvious and less obvious places including Do Home but to no avail. The internet isn't much help either but one Company (Siliconthai) in Bangkok came back with a quote roughly around the 100,000 bht mark excluding fitting and transportation. Similar options exist in neighbouring Countries but although a hel_l of a lot cheaper, if you try and import we are up to the same figure or more!!! The one in Bangkok was in fact made in Thailand and not an import!!!

I have no problem travelling a bit to be able to find one of these things but is there someone out there who can point me in the right direction???

I did have a second idea and that was to use a split load CU and just run the heavy stuff solely from one of the splits but with a AVR for those items only. Unfortunately I have no idea whether doing that would still cause problems with lights dimming etc etc or would it be better to stick with plan A and use an AVR for everything???

Any ideas please?????

[danfred]

have you considered converting to 3-phase power? i think i read somewhere the power is more balanced or smooth or something like that. we have 3-phase, 30/90 amp service at the house here in Roi Et and i'm running 4 x 60,000 BTU and 1 x 36,000 BTU air conditioning units (all 3-phase) PLUS 3 x 13,000 BTU and 1 x 24,000 BTU units (all single-phase) and even turning them ALL on at the same time (i only tested this once!) does not cause any lights to flicker or any other perceivable load on the electrical system (of course in reality only 1-3 air conditioners are ever running at the same time).

i'm from the US and they don't use 3-phase for residential use so i didn't think i needed it. but the thai electric company said i had to have 3-phase because of the number of amps i wanted (i wanted as close to 100 amps as possible). the cost was about 40,000 baht for them to install the 3-phase meter at the front of the property and about 35,000 baht for the wire and poles to the house (about 90 meters). of course you also need a 3-phase breaker box (about 6,000 baht for 30 slot Square-D box with 100amp main breaker included and 100 baht for each circuit breaker). so that's about 80,000 baht and you'll have plenty of power to spare.

good luck!

[danfred]

oh and i should mention checking your individual circuits. all my AC units are on their own dedicated circuits. however i do have a 6000 watt water heater and the lights DO dimm when i turn on the hot water tap... but that's because the electrician put the water heater on the same circuit as the bathroom lights.

[nobber9999]

oh and i should mention checking your individual circuits. all my AC units are on their own dedicated circuits. however i do have a 6000 watt water heater and the lights DO dimm when i turn on the hot water tap... but that's because the electrician put the water heater on the same circuit as the bathroom lights.

Danfred,

Many thanks for some details of your experience. I had in fact read somewhere that 3 phase would probably sort out the problem but was told by the local power Company staff in Jakkarat that I could not have 3 phase because I was not a registered business! I think I may do what you did and tell them the power I need and see if that has any effect. Probably water off a ducks back as usual as its easier to say no with authority rather than say I don't know but I will ask someone!!!!

I have had the house rewired recently including an earth all round on proper 3 core wire but believe it or not the wire still manages to change colour prior to meeting up with the fitting!!!!! I find it quite amazing that the idea of "waste not" especially when they are not paying for the wire and you have already told them to keep the same colour code throughout, they still manage to find bits of different coloured wires to throw the task into confusion. I still rely on my multi meter even when the job has been done by a "qualified sparky" !!!!! I tried to get a split load C/Unit but its like hitting your head against a wall so I think I will reforet to 2 c/u's instead.

Thanks again for your help...

Nobber9999

[crazyeddie]

I live in Korat and have 30 + years experience working as a ship's engineer. I do have a pretty good understanding of electricity and would be willing to look at your system and possibly offer some helpful advice. When one of your pumps starts, the motor initially draws "starting amps", which is a brief spike. Volatge being the inverse of amperage (Ohm's Law), this would cause a voltage drop of roughly equal duration. May I ask what is the problem being caused by this not so stable voltage? If it is your computer, then just get a UPS. Sounds to me like your service is less than adequate, as in too small a wire gauge or poor connections in the circuit somewhere. First rule of electrical work is "Make a visual inspection". Look for burned looking components and connections. Use your nose; is there any odor of burning electrical insulation? This would all cause voltage drops as amp flow increases. The use of 3 phase power would be nice, as you could use 3 phase motors of 450-480 VAC nominal rating. Draw much less amps that way, and the motors can last nearly forever with no maintenance. The only AVR I can think of at the moment is the kind used to regulate the output of an alternator or generator. I do not think this would apply in your case, as you are hooked up to the public power grid. Another rule to remember is: "If it ain't broke, don't fix it". Good luck!