Stabilizer for Air Conditioners

The name plate of the AC Unit will provide information on its power consumption.

Are all the units fed from a common location? If not how can you use a single stabilizer?

Who will be doing the installation? You?

Hi,

All the A/C's draw the power from the transformer and the connection is through Bus bar. By the way our electrician does this, but he is not having knowledge on these Voltage stabilizer. The primary thing now for us to know how much KVA stabilizer required for each of the 04Tonne A/C,

Best Regards,

Venkata Ramakrishna

If your electrician can't find that information on the nameplate and figure out how to wire it up, then it's time to hire one who can do more than just twist wirenuts.

Everything usually draws power from a transformer or generator. But I was talking about the final distribution. A typical 4 ton DX type condensing unit needs around 6KW power. And you need to know if it has a built in means of power factor correction to calculate the KVA of the stabilizer. Consult the manufacturer if you can't find the information. What does your local regulations say about this?

People from different countries are the ones answering here. Somebody who works within your locality would be best suited to solve this.

What components are being damaged?

Your indicating 4 Ton AC capacity, is this single phase condensing units?

What protection devices are on this system e.g. short-cycle timer.

Trying to understand if these are single phase systems, that have start/run capacitors.

Things you need to identify first and established before buying the needed voltage stabilizer(s);

1. What is causing the frequent power issues in your place?

2. Do you have the proper size of wiring conductors and distribution in your building?

3. Is the power issues local only inside OR also happening outside your facility (whole city)?

4. What is the minimum and the maximum voltage variations? Beyond allowable +/-10% ?

5. How frequent and how long the duration of voltage variations?

.

More important than stabilizer is time delay between loss of Mains Power and Return.

Reason being,

with Compressor running and if there is a short interruption in supply or heavy dip that compressor stops - on immediate return of Power Supply the motor is unable to start the compressor.

Reason being that there is already a pressure difference of approximately 200 lb/Sq inch between discharge and suction end of compressor.

As a result the motor draws very heavy current (6 to 8 times its full load current), without any cooling (because it is not turning) - called lock rotor condition of induction motor.

End result is that it is tripped by thermal over load relay.

The Thermal Overload relay in compressors (hermetically sealed) is of self reset type - which reset after some time and if the pressure on both end has not equalized above overload repeats.

Subjecting compressors motor to above type of repeated operation results in weakening of winding that it burns.

Hence what is more important is that once the compressor stalls and supply returns.

In case of Split units:

1. Only evaporator (fan coil unit which is mounted inside the building for cooling) shall be started first for a minute at least.

2. The compressor shall be started after a delay of one minuets.

For windows A/C,

The delay shall be at least 3 minuets for compressor to equalize its high and low side pressure.

For small packages up to 1.5 ton you get stabilizers with Optional Timer in India.

Earlier this used to be in all small packages, but with improved electronics (Microprocessor based controls) Now whether it a Window A/C or Split unit - this safety of first running only fan for approx. a minuet is built in.

Not a false claim - I was the first in India to invent this device that is Time Delay Relay in Small Voltage Stabilizers. That is back in 1971 - when I wanted to start my own business after graduation and assembled two 300VA stabilizers with Time Delay and went to best Electrical Dealer in the city to sell it. In nutshell the Dealer told me that he was not a qualified electrician and he had understood after 1/2 hour what I had developed. He further told that that was a very good product but should take him 1 hour to explain to Customer. I may leave the product with him and if it was sold I would be paid. (That was out of my scholarship money - did not have father and did not want to put burden on my mother). Well that was my first failure to try to be entrepreneur - made another attempt with other product - did not work out and took job.

I saw first commercial production of Stabilizer with Time delay in 1978, Alwyn Prest cold of India (a British Firm having production unit in Hyderabad then) had Full Page add in The Times of India (that was after 7 years)

Stabilizer is used for maintaining the voltage, which means that if the supply voltage fluctuates in your home, due to this fluctuation of voltage all other electronic appliances are effected by these, so for the safety of Ac and other electric appliances in our home we use Stabilizer. You must use the stabilizer in partial ratio as all is depend on the voltage of your home, like instead of using one stabilizer for one AC you can use 1 stabilizer for 2 AC, by these you can easily maintain the voltage of your house and Air Conditioners.