Undervoltage and damages

[donim]

35 minutes ago, CGW said:

44 minutes ago, Kwasaki said:

" unless you were to turn off at breaker " that's what your suppose to do. ????

? so when the power goes off you are supposed to turn the power off at the breaker, then when the power comes back on again you turn it back on again at the breaker, why - what's the difference in just leaving it? ????

 

Two storys.  The power is totally off OR the power is dancing low (brownout) as we speak of in this thread.

 

I know when the power turns off 100% , I can not controll my aircon obviously.

And when the power come back to live, so is the aircon as it remembers what it did the last.

 

At brownouts, the compressor stops working. The fan turns slowly, and the led light is going weird.

Sometimes it will listen to the commands from the remote controller and I am able to turn it off.

But if the power is very very low the miroprocessor inside the indoor unit is not able to work out the signals from the remote controller, it wouldn't listen even if an led lights on.

 

Then the breaker is the only way to cut the power, if you don't have a breaker in the room then you can find it at the consumer unit.

 

If there is no breaker in the same room as the aircon, then consider to have a breaker installed near the aircon when this happen reguarly.

[opensea]

You can ruin a compressor by wiring it wrong.  If it is wired to work in the wrong direction you can damage a compressor.  But undervoltage in general does not cause damage, stuff just wont work well or at all - voltage is what pushes the amps, the electrons. Electrons are what makes electricity work, voltage is the "pressure" that pushes the electrons through the wires - but a compressor wired wrong and working "backwards" can cause damage to the compressor even if it's underpowered, granted there's enough power to make the compressor work.

Edited May 2, 2019 by opensea

[Road Warrior]

as a retired electrician fro uk .under voltage WILL NOT DAMAGE THE STATS IN FACT LOW VOLTAGE WILL NOT DAMAGE ANY APPLIANCE

[sometimewoodworker]

11 minutes ago, Road Warrior said:

as a retired electrician fro uk .under voltage WILL NOT DAMAGE THE STATS IN FACT LOW VOLTAGE WILL NOT DAMAGE ANY APPLIANCE

Shouting does not make you correct, neither does you previous profession.

 

Prolonged low voltage will damage some motors and they can burn out

Quote

Queensland University of Technology

Motor current = (motor voltage applied - motor back emf) / winding resistance.

As the motor slows the motor back emf drops so the numerator increases and the ohmic loss in the winding increases. Ultimately it burns out.

Winding power = motor current ^2 x winding resistance.

That is one condition where low voltage damages appliances.

[Fruit Trader]

1 hour ago, Road Warrior said:

as a retired electrician fro uk .under voltage WILL NOT DAMAGE THE STATS IN FACT LOW VOLTAGE WILL NOT DAMAGE ANY APPLIANCE

I am guessing you missed the theory classes.

[khunPer]

17 hours ago, sometimewoodworker said:

For single phase use they are automatic reset over/under voltage protection device they are commonly used with a contactor 

 

Phase protection devices are designed to prevent 3 phase equipment only being fed 1 or 2 phases by cutting all 3 if 1 goes down or low/high voltage. So if you are using a 3 phase supply as 3 independent single phase supply's they are the wrong devices to use, not to mention much more expensive than you need.

Thanks for posting another option.

 

The method I described is the one used in general by electrician in the part of Thailand where I live, including the pre-manufactured control-boxed for water pumps and pool pumps for sales in many electrical parts stores; and also custom made boxed, like the one I got for three pool and Jacuzzi-pumps.

 

Often its best to just let the workers use their well known and experienced methods, the part prices were not astronomical; 680 baht for a magnetic relay, and 990 baht for a phase protector, so total part costs per phase was less than, or about, 2,000 baht. But of course, money and prices are relative.

 

However, in my view it's a cheap one off insurance fee for aircons and pumps, no matter which solution chosen for voltage deviation protection...????

[sometimewoodworker]

1 hour ago, khunPer said:

Thanks for posting another option.

 

The method I described is the one used in general by electrician in the part of Thailand where I live, including the pre-manufactured control-boxed for water pumps and pool pumps for sales in many electrical parts stores; and also custom made boxed, like the one I got for three pool and Jacuzzi-pumps.

 

Often its best to just let the workers use their well known and experienced methods, the part prices were not astronomical; 680 baht for a magnetic relay, and 990 baht for a phase protector, so total part costs per phase was less than, or about, 2,000 baht. But of course, money and prices are relative.

 

However, in my view it's a cheap one off insurance fee for aircons and pumps, no matter which solution chosen for voltage deviation protection...????

The items in my picture are.

 

The single phase Adjustable under / over voltage trip $15.60 

Contactor with over ride $8.84 + $2.61 shipping 

 

So about ฿900