# Stablizer

#1

i have purchased 'STAC' Stablizer 7000W for 1.5 ton Air Conditioner, there is no input range written on stablizer, however shopkeepr told that it will work from 160VAC, but as I have observed when input decreases to 200v the steplizer steps up to 230VAC, while at 165VAC the output become 195VAC, however it should increase upto 230VAC again. i want to know how many relays are available inside 'STAC', and will it realy work with 160VAC or not, i have not tested with any regulator, but this electricity problem is available in our city, and i have digital volt meters at input and output.

#2

I have not used that particular make/model, but my comments will apply to all stabilizers using tap-switching to regulate the AC voltage.

1) The transformer in a tap-switching stabilizer has multiple taps in the winding.

2) The number of relays inside the stabilizer depends upon how many taps the transformer has.

3) Since taps are at fixed number of turns, so don't expect a tight output regulation.

For example, consider a stabilizer that has been designed to provide regulated 220V from input (160-250V). Now this range of 250-160 = 90V should have multiple taps. The greater the number of taps in this 90V range, the better output regulation you will have. Generally the taps spaced at 10-15V provide optimum regulation. With 15V tap spacing and a good control circuit, you will have +7.5 to -7.5 Volt error (output will remain in 212 - 227V range)

In your case, what I can understand is that your stabilizer can boost the voltage by maximum 30V (because when you have 165V input, you get 195V output and when you have 200V input, the output becomes 230V)

Mostly stabilizers available in market have just two relays inside which can accommodate a maximum 3 taps. If we take one tap for 250V input, then on lower voltage side, you have 2 taps left. This is the simplest but worst design.

#3

thanks for replying but i have now observed that it steps up at about 195V(not exactly at 200V) to level of 233 or 235 but as compressor starts about 5v drops and reaches to 230 or 231V. and when main real voltage reaches to 200V for some some 'time' then it will step down and output reaches at level of 200V.

means for step up at 195V and step down at 200v,

it means it has 35V steps and contains i think 2 relays.

normally we have 185V to 195V and the output of stablizer is in b/w 215 to 225v

[quote=", post:2, topic:14789"]

I have not used that particular make/model, but my comments will apply to all stabilizers using tap-switching to regulate the AC voltage.

1) The transformer in a tap-switching stabilizer has multiple taps in the winding.

2) The number of relays inside the stabilizer depends upon how many taps the transformer has.

3) Since taps are at fixed number of turns, so don't expect a tight output regulation.

For example, consider a stabilizer that has been designed to provide regulated 220V from input (160-250V). Now this range of 250-160 = 90V should have multiple taps. The greater the number of taps in this 90V range, the better output regulation you will have. Generally the taps spaced at 10-15V provide optimum regulation. With 15V tap spacing and a good control circuit, you will have +7.5 to -7.5 Volt error (output will remain in 212 - 227V range)

In your case, what I can understand is that your stabilizer can boost the voltage by maximum 30V (because when you have 165V input, you get 195V output and when you have 200V input, the output becomes 230V)

Mostly stabilizers available in market have just two relays inside which can accommodate a maximum 3 taps. If we take one tap for 250V input, then on lower voltage side, you have 2 taps left. This is the simplest but worst design.