what should I do in a serious BROWNING ?

[ETatBKK]

hi there

last night in the rain, the electric cut off for a while then started up with very unstable very low supply. some major appliances back with power, but CFL light bulbs not able to start up, fan not turn, and of course UPS still cut off.

actually, what should I do in this situation ? totally switch off the consumer unit, or else ?

I am in a standard moo baan setting.

thanks . . .

[bankruatsteve]

I would. (shut off the main until normal voltage)

[Crossy]

Me too ^^^, the only issue of course is not knowing when the mains returns to normal.

Leaving the lighting circuit connected would be a low cost indicator of normality (we have a voltmeter on the incoming supply).

Perhaps an undervoltage relay and contactor to remove the supply automatically when it goes outside a sensible range would be a good idea if it's a regular occurance.

[Pib]

I would recommend cutting the power. I'm on single phase 220V and whenever we have a brown-out here in western Bangkok the voltage normally drops to around 100V and varies a lot....but sometimes it drops to around a 180V and may slowly vary down to around 100V (or much lower)....each brown-out seems to be different.

Now since some of my electronics work on 120V or 220V they could continue on say at around 100V but I still may kill power to them to play it safe. Now, my 220V "only" electronics can't continue on much below 180V without possible damage...maybe not immediate damage but damage if the low voltage situation is repeated too many times And my water pump will run continuously trying to rebuild water pressure if the voltage drops to only around 200V. Basically, my 220V items runs a real chance of damaging themselves unless they happen to have some type of low voltage protection built-in.

I have a voltmeter on my main circuit box power input and whenever there is a brown-out I'll look at the meter to check the voltage level and if it's varying to determine whether I want to kill power to the whole house or just certain circuits. Plus, when the power comes back I'll may wait a few minutes before turning back on the circuits breakers because many times when the power comes back it will immediately drops off a few seconds later...sometimes only once...sometimes twice....so to avoid this on-off surge I normally wait a few minutes before restoring power to the circuits.

[ETatBKK]

last night the first thing in my mind was an incandescent light bulb, but reachable I only have CFL or LED, both not able to startup. then I ran to the fan, not able to start neither. I know it was very low.

voltmeter could be a new item in the next upgrade. thanks . . .

Me too ^^^, the only issue of course is not knowing when the mains returns to normal.

Leaving the lighting circuit connected would be a low cost indicator of normality (we have a voltmeter on the incoming supply).

Perhaps an undervoltage relay and contactor to remove the supply automatically when it goes outside a sensible range would be a good idea if it's a regular occurance.

[ETatBKK]

is there any 'low voltage protection' I could build into the CU ?

when I am not at home, it could help to cut off the power in the brown-out.

I would recommend cutting the power. I'm on single phase 220V and whenever we have a brown-out here in western Bangkok the voltage normally drops to around 100V and varies a lot....but sometimes it drops to around a 180V and may slowly vary down to around 100V (or much lower)....each brown-out seems to be different.

Now since some of my electronics work on 120V or 220V they could continue on say at around 100V but I still may kill power to them to play it safe. Now, my 220V "only" electronics can't continue on much below 180V without possible damage...maybe not immediate damage but damage if the low voltage situation is repeated too many times And my water pump will run continuously trying to rebuild water pressure if the voltage drops to only around 200V. Basically, my 220V items runs a real chance of damaging themselves unless they happen to have some type of low voltage protection built-in.

I have a voltmeter on my main circuit box power input and whenever there is a brown-out I'll look at the meter to check the voltage level and if it's varying to determine whether I want to kill power to the whole house or just certain circuits. Plus, when the power comes back I'll may wait a few minutes before turning back on the circuits breakers because many times when the power comes back it will immediately drops off a few seconds later...sometimes only once...sometimes twice....so to avoid this on-off surge I normally wait a few minutes before restoring power to the circuits.

[Crossy]

is there any 'low voltage protection' I could build into the CU ?

when I am not at home, it could help to cut off the power in the brown-out.

Yes, assuming single-phase get one of these http://www.ebay.co.uk/itm/Adjustable-Over-Under-Voltage-Protective-Relay-/221381033800?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item338b567f48 and use it to drive a suitable contactor (a giant relay) maybe like this http://www.ebay.co.uk/itm/Schneider-15959-CT-Double-Pole-25a-NO-Contactor-240v-Coil-Used-/151031227579?pt=UK_BOI_CircuitBreakers_RL&hash=item232a29a4bb (parallel contacts for higher current).

Note: If you go direct to GenControl this unit is cheaper (they do ship to Thailand), they have 3-phase units too.

[ETatBKK]

very nice ! but seems this type of device is not available in Thailand. and a Thai electrician not able to understand it :-(

one more detail though - it seems this relay automatic switching off the mains when it confronts with brown-out. when the supply voltage stabilised, would it switch the mains back on again ? just concerns if we don't back home that evening, everything will be off then.

is there any 'low voltage protection' I could build into the CU ?
when I am not at home, it could help to cut off the power in the brown-out.

Yes, assuming single-phase get one of these http://www.ebay.co.uk/itm/Adjustable-Over-Under-Voltage-Protective-Relay-/221381033800?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item338b567f48 and use it to drive a suitable contactor (a giant relay) maybe like this http://www.ebay.co.uk/itm/Schneider-15959-CT-Double-Pole-25a-NO-Contactor-240v-Coil-Used-/151031227579?pt=UK_BOI_CircuitBreakers_RL&hash=item232a29a4bb (parallel contacts for higher current).

Note: If you go direct to GenControl this unit is cheaper (they do ship to Thailand), they have 3-phase units too.

[Crossy]

very nice ! but seems this type of device is not available in Thailand. and a Thai electrician not able to understand it :-(

If you find an electrical specialist outlet rather than HomeWorks etc. they should know what you want and have / be able to order same (along with the associated contactor).

It's not rocket science to connect up, if your sparks doesn't understand, get another sparks.

If you do get a unit and contactor, post details here and I'll do a simple connection diagram for your man.

EDIT in fact the Ebay link has the connection diagram

[CharlesHH]

"Brown-outs" are the accidental or purposeful reduction of voltage supplied to your home.

Most Thai appliances can work down to about 180 volts (VAC) but the devices which convert the needed 220 VAC to the various voltages INSIDE the appliance are stressed via higher heating which will accelerate their failure.

Most fixed 220VAC electronics devices will heat lots on lower voltages, and parts inside will fail especially if the units are on.

Many modern items use either a "wall transformer" the cube that plugs into the wall and its trailing wire plugs into your device, or a transformer with a wire to plug into the wall and a trailing wire to plug into the device. Read on the transformer case which usually indicates it will work from 100 VAC to 250VAC meaning it should be immune to brown-outs (above 100). These units can just go on running with no expected increased failure rates.

Operating any other device at voltages below about 180 VAC will produce significant heating and a danger of fire, or will just stop working, like a fan.

A cheap way to keep an eye on your voltage is to have one incandescent light bulb turned on, not LED and not fluorescent, and see what the light output is at normal and how it looks at low voltage. A volt meter is better.

Thailand shops sell transformers, called "step up", to install for a whole house or a room which has a meter and a switch on it so if 180VAC is shown coming in, the switch can be turned to another position indicating that it is passing a higher voltage on to the house or room. These devices do work, and local electricians know about them. My family always turned ours to the lowest setting (behind my back) because they reasoned wrongly that the lower the voltage, the lower the cost for electricity.

The opposite is true due to waste electric energy that just heats appliances, etc.

Another danger is total loss of all electric power and then reinstating it. Although this can confuse certain timing circuits, usually it is no harm, EXCEPT if the voltage does not come back on at full 220VAC; then you are at the brown-out problem again. The return of power also can contain a higher than normal voltage; also not good for electrical devices.

It is best to avoid using any device at voltage lower than 180. Just turn them off and wait, or unplug them. Ask more if this is not complete enough.

[Crossy]

+1 Charles ^^^

Thailand shops sell transformers, called "step up", to install for a whole house or a room which has a meter and a switch on it so if 180VAC is shown coming in, the switch can be turned to another position indicating that it is passing a higher voltage on to the house or room. These devices do work, and local electricians know about them. My family always turned ours to the lowest setting (behind my back) because they reasoned wrongly that the lower the voltage, the lower the cost for electricity.

A better (but slightly more expensive) solution is the AVR (Automatic Voltage Regulator) sometimes called a stabilizer, does what Charles' device does but fully automatically, no need to fiddle with switches.

Available in sizes from < 500VA to 15KVA and above.

[tifino]

yeah I reckon a Stabiliser as just mentioned could be a safe way out.

I have tried using UPS blocks, but the inpiut variances eventually takes the UPS out.

Another experiment I have dabbled in is to utilise a Mains Delay device:

typical example, which you can search for whatever VA capacity neede for your application:

http://www.ebay.com.au/itm/120855536282?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

- purely to protect the UPS from repeatedly being tortured.

these surges, especially the micro-duration ones do most of the damage.

Apply one of the above to mains input for the UPS, and another on the UPS's output.

If the duration of the brownout is short, the UPS will carry the Load for that short time.

If there happens to be a longer duration i.e. power failure, where the UPS finally drains out, then:

Upon restoration of usable mains power, the UPS starts, and the 2nd device protects (the supplied equipments) from the UPS while it is starting up and still reaching usable output.

The same units are applicabe for protection of airconditioners, from restarting too quickly, on a short duration brown out