Low voltage single phase - whole house stabilizer or get 3 phase and split?

[bankruatsteve]

Could be carlyai's genset is typical of the Chinese versions that have (?) AVR's that just don't push out for the rated amps. Although, I don't have experience with genset that ever does deliver max amps. The ones I have will shake rattle and role when they get close to max and it's like - OK baby we won't do that to you again.

[carlyai]

The gen set feeds into the changeover switch. Changeover switch is: mains on genset off, both off, genset on mains off.

Where are the AVRs in relation to the changeover?

Genset breaker rating?

[carlyai]

I can't see the breaker rating, and someone left my user book out in the rain. I will try and get inside the genset cover tomorrow to check the breaker rating.

My 3 Lioa Avrs are between the mains and the input to the change over switch. So when i rotate the switch to gen set position they should not be in circuit.

When i was adjusting the house load to the genset, i did notice that at around 14A supplied from the genset was Ok, but then when i turned another airconditioner on to increase the load, the genset voltage dropped to about 215-218 v, so I shed that load.I was still not drawing near 20 A.

The genset has it's own Avr on it's output.

I presume that the genset can't supply the 22.7A or 5Kva.

[carlyai]

Could be carlyai's genset is typical of the Chinese versions that have (?) AVR's that just don't push out for the rated amps. Although, I don't have experience with genset that ever does deliver max amps. The ones I have will shake rattle and role when they get close to max and it's like - OK baby we won't do that to you again.

[carlyai]

Could be carlyai's genset is typical of the Chinese versions that have (?) AVR's that just don't push out for the rated amps. Although, I don't have experience with genset that ever does deliver max amps. The ones I have will shake rattle and role when they get close to max and it's like - OK baby we won't do that to you again.

[carlyai]

I think this is the case with my little Chinese genset.

Now I'm not too sure how they rate gensets, but there is probably some technical graph data somewhere that lets them claim 5kva or 22.7A.

Anyway it's all good to know, and without Crossy's meter suggestion I Still wouldn't know how much current i was drawing.

For anyone else that drives a single phase genset into 3 seperate phases, the first time i thru the genset breaker, the 3 phase SafetyCut tripped, but when i reset it , it never tripped again. (The genset goes thru a 3 phase changeover switch into the SafetyCut).

[carlyai]

Carl.

Are you typing replies? None of your recent posts seem to contain any text.

Seems I have trouble when I use my mobile phone with TV.

I am now using my laptop, and can see now that there is no text, where I see text that I typed using the iphone.

[Crossy]

Carl.

Are you typing replies? None of your recent posts seem to contain any text.

Seems I have trouble when I use my mobile phone with TV.

I am now using my laptop, and can see now that there is no text, where I see text that I typed using the iphone.

You may wish to post in Forum Support for some idea of what's going wrong.

[Naam]

thread: http://www.thaivisa.com/forum/topic/671566-voltage-drop-solved/page-2

Naam, on 13 Apr 2015 - 11:05, said:

IMHO, on 13 Apr 2015 - 09:54, said:

well, it's obvious not applicable in my case. installing the stabiliser between public grid and my "thingy" would most probably trigger one of the fuses of the thingy when low voltage causes high amps. installation after the "thingy" won't help because of the automatic shutdown.

is my thinking correct? if yes, how was it possible that IMHO's gadget had an output of 90 amps without blowing any of his regular fuses?

Here's my setup:

Meter > Stabilizer > 3 CU's (one of them 70-80M away & via a 63A Safe-T-Cut)

The only over-current protection I have in ultra-low voltage situations is the 2 pole 100A breaker in the stabilizer itself - it has so far never tripped, but the unit has shut down in severe brownouts/blackouts.

I can't see why this wouldn't work for you - your "thingy" will never see low voltage/high amps - only the stabilizer sees that.

going to Global House, Chonburi today to look what is available and (very important) taking measurements.

plan: 3 x single phase 20kva units or perhaps each 15kva after a revised max load calculation.

[Naam]

Also, don't forget that a 10kW load on the output @ 220V drawing about 45A will draw nearly 60A on the input side if the supply is down to 170V.

If your incoming breaker is 50A then that's about the limit.

my incoming breaker is Siemens 5SX73 50A (i assume 50A each phase), = can i increase capacity without any problems?

Crossy, can you confirm IMHO's claim your "thingy" will never see low voltage/high amps - only the stabilizer sees that ?

[crs]

Is stabilizer same as AVR? In any case, what happens if load exceeds capacity?

Yes. Overload it and its incoming breaker will open, cutting off the supply and protecting the AVR.

Also, don't forget that a 10kW load on the output @ 220V drawing about 45A will draw nearly 60A on the input side if the supply is down to 170V.

If your incoming breaker is 50A then that's about the limit.

I'm a little concerned about total amp draw on my 15/45 meter if incoming voltage is relatively low. I'm not so worried about the 63A amp MCBs I have fitted now - but am worried a little worried about the 45 meter.

What exactly would happen if the meter is overloaded? Will it just trip out somehow or blow? No chance of it happening until next hot season but...

I could swap out 63A MCBs in the CU and pre-stabiliser for 100A MCBs and upgrade to a 100 meter, I guess. (The stabiliser already has a 100A breaker.)

Cheers.

[Naam]

I'm a little concerned about total amp draw on my 15/45 meter if incoming voltage is relatively low. I'm not so worried about the 63A amp MCBs I have fitted now - but am worried a little worried about the 45 meter.

What exactly would happen if the meter is overloaded? Will it just trip out somehow or blow? No chance of it happening until next hot season but...

I could swap out 63A MCBs in the CU and pre-stabiliser for 100A MCBs and upgrade to a 100 meter, I guess. (The stabiliser already has a 100A breaker.)

Cheers.

that would have been my next question.

[Crossy]

Electricity meters are very robust. A 15/45 will quite happily supply a 100% overload pretty well forever so I wouldn't worry about it being on a 63A incomer although that is the biggest I would use. PEA won't permit anything over 50A on a new installation (at least our local office won't).

The incomer will open well before the meter suffers any ill effects.

[crs]

Thanks, Crossy. No worries then

[Naam]

Electricity meters are very robust. A 15/45 will quite happily supply a 100% overload pretty well forever so I wouldn't worry about it being on a 63A incomer although that is the biggest I would use. PEA won't permit anything over 50A on a new installation (at least our local office won't).

The incomer will open well before the meter suffers any ill effects.

how does that tally with IMHO's claim?

When we tested mine, a load of just 12,000 watts was using 90 amps of supply current to stabilise to 220V (i.e. supply voltage dropped to 130'ish)

http://www.thaivisa.com/forum/topic/671566-voltage-drop-solved/#entry7574922

[Crossy]

Electricity meters are very robust. A 15/45 will quite happily supply a 100% overload pretty well forever so I wouldn't worry about it being on a 63A incomer although that is the biggest I would use. PEA won't permit anything over 50A on a new installation (at least our local office won't).

The incomer will open well before the meter suffers any ill effects.

how does that tally with IMHO's claim?

When we tested mine, a load of just 12,000 watts was using 90 amps of supply current to stabilise to 220V (i.e. supply voltage dropped to 130'ish)

http://www.thaivisa.com/forum/topic/671566-voltage-drop-solved/#entry7574922

IMHO doesn't indicate his incoming breaker size. Assuming it is 63A then @ 90A it should last 5-10 minutes before the thermal element opens it.

I see no conflict, 12kW @ 90A indicates a supply of about 130V.

[crs]

For me, if the meter isn't the weak point, I'll know to upgrade meter and breakers to 100A if my 63A breakers ever trip...

Also, my stabiliser cuts out at <150 or 160v - so a really high amps draw due to a really low voltage shouldn't happen.

I've even got an adjustable voltage range control switch I could wire in pre stabiliser if I want to limit the operation range further - eg. to +180v - but can't see that being necessary.

[bankruatsteve]

I thought the stabilizer in front of CU? Or, not? If in front and it's stabilizing to 220v then wouldn't the CU be seeing the "normal" 55 amps?

[Naam]

Electricity meters are very robust. A 15/45 will quite happily supply a 100% overload pretty well forever so I wouldn't worry about it being on a 63A incomer although that is the biggest I would use. PEA won't permit anything over 50A on a new installation (at least our local office won't).

The incomer will open well before the meter suffers any ill effects.

how does that tally with IMHO's claim?

When we tested mine, a load of just 12,000 watts was using 90 amps of supply current to stabilise to 220V (i.e. supply voltage dropped to 130'ish)

http://www.thaivisa.com/forum/topic/671566-voltage-drop-solved/#entry7574922

IMHO doesn't indicate his incoming breaker size. Assuming it is 63A then @ 90A it should last 5-10 minutes before the thermal element opens it.

I see no conflict, 12kW @ 90A indicates a supply of about 130V.

what could happen if i replace my 50A breaker with a 100A one? if i leave the present 50A it makes no sense to install stabilizers which might draw >50A for an extended period of time. perhaps my logic is flawed?

[crs]

I thought the stabilizer in front of CU? Or, not? If in front and it's stabilizing to 220v then wouldn't the CU be seeing the "normal" 55 amps?

Got a 63A MCB before the stabiliser (as an isolator more than anything - but this should also safeguard the meter) and the CU with 63A breaker after stabiliser.

[Crossy]

@Naam

If you are on a 15/45 your 100A breaker wouldn't think of opening before 120A possibly more, meters are robust, but that's really taking the Michael.

A 63A incomer is the biggest I would be happy putting on a 15/45.

If it's really an issue then upgrade to a 30/100 meter which will be more than happy on a 100A MCB.

[bankruatsteve]

I thought the stabilizer in front of CU? Or, not? If in front and it's stabilizing to 220v then wouldn't the CU be seeing the "normal" 55 amps?

Got a 63A MCB before the stabiliser (as an isolator more than anything) and the CU with 63A breaker after stabiliser.

OK but if (was it IMHO?) had 130v and drawing 90 amps from the grid then he must have a 12KVA stabilizer, right? Or (back to my earlier question) it seems the AVR would have tripped. It seems any breaker or AVR capacity should consider the capacity of the mains cable and that's it. (?)

[crs]

I thought the stabilizer in front of CU? Or, not? If in front and it's stabilizing to 220v then wouldn't the CU be seeing the "normal" 55 amps?

Got a 63A MCB before the stabiliser (as an isolator more than anything) and the CU with 63A breaker after stabiliser.

OK but if (was it IMHO?) had 130v and drawing 90 amps from the grid then he must have a 12KVA stabilizer, right? Or (back to my earlier question) it seems the AVR would have tripped. It seems any breaker or AVR capacity should consider the capacity of the mains cable and that's it. (?)

I think it mentions a 20kva stabiliser in that thread. If so, they have a 100A breaker. (Think it is the same Liao model as mine, actually - so thought it would have cut out already before reaching such a low voltage???)

EDIT: models specs here: http://www.lioa.com/en/san-pham/ap-ap-1-pha/automatic-voltage-stabilizer-1-phase (Maybe does go down to 130v? hard to know for sure from the specs.)

[Crossy]

It seems any breaker or AVR capacity should consider the capacity of the mains cable and that's it. (?)

Soooo, by that logic I can put some 35mm² copper on a 5/15 meter and pull 140A ?

[bankruatsteve]

Except for use of breaker as an isolator in front of the stabilizer I'm not getting where the CU main breaker even matters.

[bankruatsteve]

It seems any breaker or AVR capacity should consider the capacity of the mains cable and that's it. (?)

Soooo, by that logic I can put some 35mm² copper on a 5/15 meter and pull 140A ?

Yeah, maybe. Do you know of any meters that have melted?

[Crossy]

Except for use of breaker as an isolator in front of the stabilizer I'm not getting where the CU main breaker even matters.

It doesn't any more

But it's cheaper to leave it in than to replace with an isolator.

The breaker in front of the stabiliser is what is now protecting the supply.

[crs]

Except for use of breaker as an isolator in front of the stabilizer I'm not getting where the CU main breaker even matters.

No, it won't be the break point now - but not much point in taking it out. (The CU was fitted prior...)

EDIT: posted same time as Crossy - and, yes, you do still need a way to isolate there...

[crs]

It seems any breaker or AVR capacity should consider the capacity of the mains cable and that's it. (?)

Soooo, by that logic I can put some 35mm² copper on a 5/15 meter and pull 140A ?

Yeah, maybe. Do you know of any meters that have melted?

Yeh - do they melt or what???

[Crossy]

It seems any breaker or AVR capacity should consider the capacity of the mains cable and that's it. (?)

Soooo, by that logic I can put some 35mm² copper on a 5/15 meter and pull 140A ?

Yeah, maybe. Do you know of any meters that have melted?

Yeh - do they melt or what???

A 5/15 with a 10x overload will likely go bang!

Taking it past 2 x rated current will cause loss of accuracy (they never read low of course) and eventually the current sense coil will overheat and fail open circuit.

In reality they will likely just stop working but it is generally unwise to continuously operate any piece of electrical kit beyond it's maximum ratings.

EDIT Of course if you fry your meter the electricity authority will want to know why and may come a-calling to inspect your installation.