★ 4.9
In stock · dispatch in 3–5 days
Simple, Affordable Protection for Homes and Shops
Servolink automatic voltage stabilizers are relay type stabilizers for homes, flats, shops and small offices. They come in two forms: a mainline stabilizer, installed once after the meter to protect the whole house, and an AC stabilizer, which protects one air conditioner.
Both correct the voltage in steps by switching relays between transformer tappings. This keeps the output inside a safe band around 230 V — which is all that ACs, fridges, pumps and household appliances need. They cost much less than a servo stabilizer, install easily, and need almost no maintenance.
SERVOLINK makes mainline stabilizers in ratings 3, 5, 7.5 and 10 kVA and AC stabilizers in 3, 4 and 5 kVA, with copper wound transformers made in our own factory in Ghaziabad.
Voltage in residential colonies and markets is rarely steady. It dips in the evening when everyone switches on ACs and lights, and shoots up late at night when the load drops. Appliances designed for 230 V slowly wear out on this — compressors run hot, PCBs fail and motors burn.
A typical home today also has far more electronics than the one or two appliances people usually protect: LED lights and drivers, BLDC fans, a washing machine with a control card, a water pump, a microwave, TVs, a Wi-Fi router and an inverter charging its battery. Buying a separate stabilizer for each one is costly and still leaves most of the house unprotected. Correcting the voltage once — at the meter, or right at the AC — is the simple answer.
Inside is an auto-transformer with several tappings and a set of relays. The control card reads the input voltage all the time. When the voltage drops, it switches a relay to a higher tapping, which boosts the output; when the voltage rises, it switches to a lower tapping, which reduces it. Each relay step corrects the voltage by a fixed amount, so the output stays inside a safe band around 230 V.
This step correction is right for household appliances, because they need a voltage inside a safe range, not an exact voltage. For equipment that needs ±1% accuracy, a servo stabilizer is the better choice.
A mainline stabilizer is connected once, after the electricity meter and main switch, and before the distribution board (MCB box). Every circuit in the house then gets corrected voltage — lights, fans, pumps, the inverter and every appliance — without a separate stabilizer at each socket.
Add the wattage of everything that runs together — ACs, fridge, pump, geyser, lights and fans. Divide by 1000 to get kW, and divide by 0.8 to get kVA. Then choose a rating so that this load stays around 60–70% of the stabilizer rating. Or use our kVA calculator.
If your house runs 3 or more ACs together, a lift, or medical and lab equipment, choose a single phase servo stabilizer instead.
An AC stabilizer is wall mounted next to the AC and sized for that one AC, with a compressor time delay built in. For up to 1 ton choose 3 kVA, for 1.5 ton choose 4 kVA, and for 2 ton choose 5 kVA.
See our AC Stabilizer page for full details.
| Point | Mainline Stabilizer | AC Stabilizer |
|---|---|---|
| Protects | Whole house or shop | One AC |
| Ratings | 3–10 kVA | 3 – 5 kVA |
| Connected | After the energy meter | At the AC’s power point |
| Mounting | Wall mounted | Wall mounted |
| Time delay | Yes | Yes |
| High / low cut-off | Yes | Yes |
| Point | Automatic (Relay) Stabilizer | Single Phase Servo Stabilizer |
|---|---|---|
| Correction | In steps, through relays | Smooth, through motor-driven variac |
| Output accuracy | Safe band around 230 V | 230 V ±1% |
| Ratings | 3, 4 & 5 kVA | 3 – 50 kVA |
| Price | Lower | Higher |
| Best for | Homes and shops on a budget | Many ACs, clinics, offices, sensitive equipment |
| Parameter | Mainline Stabilizer | AC Stabilizer |
|---|---|---|
| Type | Relay type (step tapping) | Relay type (step tapping) |
| Capacity | 3 – 10 kVA | 3, 4 & 5 kVA |
| Supply | Single phase, phase + neutral | Single phase, phase + neutral |
| Input Working Range | 90-280 V · 110-280 V · 130-280 V · 170-280 V | 90-280 V · 110-280 V · 130-280 V · 170-280 V |
| Output Voltage | 200–240 V | 200–240 V |
| Frequency | 50 Hz | 50 Hz |
| Time Delay | 10 sec | 10 sec |
| Protection | High/low cut-off, time delay | High/low cut-off, time delay |
| Display | Digital, input and output voltage | Digital, input and output voltage |
| Transformer | Copper wound, made in-house | Copper wound, made in-house |
| Mounting | Wall mounted | Wall mounted |
We have been making stabilizers since 1980 at our own 16,000 sq ft factory in Ghaziabad. The transformer in every automatic stabilizer is wound in-house, and every unit is tested before dispatch. Buying direct from the manufacturer means factory pricing and service from the team that built your stabilizer.
After the electricity meter and the main switch, before the distribution board (MCB box). Get it installed by a qualified electrician.
No. The mainline stabilizer already protects every AC in the house, as long as it is sized for the total load.
That is the time delay. After a power cut, the gas inside AC and fridge compressors is still under pressure. The stabilizer waits until it settles, so the compressors do not restart under strain.
That is the relay changing taps when the voltage changes. It is normal. Very frequent clicking means your supply voltage is changing a lot.
The stabilizer cuts off the output to protect your appliances, and switches back on after the time delay once the voltage returns. If this happens often, your area needs a wider-range servo stabilizer.
Yes. Connect the inverter after the mainline stabilizer, so the inverter also gets stable voltage while charging its battery.
ISO 9001:20152024–2027
NSIC Registration2025–2027
MSME / UdyamRegistered 2021
Importer–Exporter CodeIssued 2019
Industrial Registration2010 record
CE — Certificate of Compliance2015–2016 record
NSIC–ONICRA Rating2016–2017 rating
ISO 9001:20152021–2024
ISO 9001:20152018–2021
ISO 9001:20082015–2018
ISO 9001:20082011–2014
Tell us the appliances you want to protect, or the size of your AC, and we will tell you the right rating. Buying direct from the factory means factory pricing and service from the team that built your stabilizer.
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