what capacity voltage stabilizer to buy?

[rahulmumbai]

hi guys!! I just bought a 29 inch CRT TV,and AIRTEL DTH set top box for DTH service.now there is lot of electricity fluctuation problem in my area.hence i am looking for a voltage stabilizer that can protect TV as well as set top box.now voltage stabilizers normally come in capacity like 200VA,300VA,500VA etc.but since i have two equipments to protect,what will be the correct rating i should go for?will the 300VA be sufficient or should i go for 500VA one,how to calculate?Thanks.

 

[adder]

hi guys!! I just bought a 29 inch CRT TV,and AIRTEL DTH set top box for DTH service.now there is lot of electricity fluctuation problem in my area.hence i am looking for a voltage stabilizer that can protect TV as well as set top box.now voltage stabilizers normally come in capacity like 200VA,300VA,500VA etc.but since i have two equipments to protect,what will be the correct rating i should go for?will the 300VA be sufficient or should i go for 500VA one,how to calculate?Thanks.

well a ur airtel set top box consumes 25watts of power and a ur 29inch tv would consume about 160 to 170watts,so assuming u wont add any other device to ur stabilizer u are fine with a 300va but since u may add more devices in future like a dvd player etc recomended to get 500va which can take a load of around 300watts.

 

[asheet]

Hi
Pl understand how the Stablilizer rating is calculated.

VA is not same as wattage. VA is just a multiple of Voltage x current.
Wattage is Voltage x current x power factor. For all inductive loads, the power factor is less than 1. So actual Wattage will be less but VA will be more.

Method of selecting stabilizer :-
1. Chk the Voltage & current rating of the device. It will be written on the sticker near power socket else check teh manual.
2. Voltage will be 220V always.
3. So multiply 220 x Current of all devices and then add the individual devices VAs. Suppose your final figure after adding all VAs is 500, add 25% safety margin to arrive at Stabilizer rating. If u r planning to add more devices later, keep buffer for them.

Hope this helps.

In case ur Stabilizer has a rating in watts also, assume a Power factor of 0.8.

 

[janitha]

In addition to what asheet has said, you have to consider the surge current which flows when you switch on the TV. Depending on the circuitry and picture tube, (eg. the earlier Sony Trinitron which needed a heavy surge) it can be few times the normal usage current.

 

[rahulmumbai]

Hi
Pl understand how the Stablilizer rating is calculated.

VA is not same as wattage. VA is just a multiple of Voltage x current.
Wattage is Voltage x current x power factor. For all inductive loads, the power factor is less than 1. So actual Wattage will be less but VA will be more.

Method of selecting stabilizer :-
1. Chk the Voltage & current rating of the device. It will be written on the sticker near power socket else check teh manual.
2. Voltage will be 220V always.
3. So multiply 220 x Current of all devices and then add the individual devices VAs. Suppose your final figure after adding all VAs is 500, add 25% safety margin to arrive at Stabilizer rating. If u r planning to add more devices later, keep buffer for them.

Hope this helps.

In case ur Stabilizer has a rating in watts also, assume a Power factor of 0.8.

hi asheet!!thanks for a very detailed reply.my samsung TV has
115 watt power mentioned on its back cover sticker.so lets do the calculation, please correct me if iam wrong. as per the formula, 1) wattage=voltage X current X powerfactor
2)VA=voltage X current
lets assume power factor of 0.8 for TV as well as the set top box.

calculating total VA for TV:
wattage=voltage X current X powerfactor
115=220 Xcurrent X 0.8
115
current = ------------ =0.653 amps 0r roughly 0.7 amps
220 X0.8

VA = voltage X current
VA = 220 X 0.7
VA =154
now considering safety margin of 25% , 154 X 1.25=192.5 VA or roughly 200 VA is required for TV alone.

calculating total VA for SET TOP BOX:

wattage=voltage X current X powerfactor
25=220 Xcurrent X 0.8
25
current = ------------ =0.142 amps 0r roughly 0.15 amps
220 X0.8

VA = voltage X current
VA = 220 X 0.15
VA = 33. considering safty margin of 25 % , 33 X 1.25 =41.25 or roughly 50 VA.

so total VA = 200(TV) + 50 (STB) =250 VA Required.

also considering what janitha mentioned about "surge current" i guess 300 VA is what i should be looking for.hope i have got the calculations right. i am looking for V-guard stabilizer,is there any other good brand ?