Servolink Sizing Engine

Find the Right Servo Stabilizer

Select your appliances or equipment and Servolink will automatically calculate the connected load, running kVA, safety margin and recommended stabilizer capacity.

🏠 Domestic 🏢 Commercial 🏭 Industrial 📄 Print / PDF Report

1 Select Application

Choose the type of installation to load the relevant equipment library.

2 Electrical System

Select phase, input voltage range and sizing margin.

3 Select Appliances / Equipment

Tap an appliance to add it. Tap again to increase quantity.

4 Your Connected Loads

Adjust quantities or remove items from your load list.
Equipment W / Unit Qty Total

5 Add Custom Equipment

For equipment not available in the preset library.
Recommended
0 kVA
Select appliances below

What Is a Servo Voltage Stabilizer?

A servo voltage stabilizer is equipment designed to stabilize unstable incoming input voltage. It continuously monitors the input supply voltage, senses irregular voltage flow, and automatically makes corrections so that it provides a stabilized output voltage to the connected appliances.

The main role of a servo voltage stabilizer is to protect electrical and electronic equipment. Since we cannot sense voltage fluctuations visually, these fluctuations can lead to permanent damage to equipment, reduced performance, and unexpected shutdowns. To prevent this damage, a servo voltage stabilizer corrects the input voltage supply before it reaches the connected load.

Why Correct Sizing Matters

An undersized stabilizer will overload and trip repeatedly, or fail to protect connected equipment during voltage surges. An oversized unit costs more upfront and wastes standby power. The Servolink sizing engine calculates your actual running load (kVA), factors in motor starting current for compressors and pumps, and applies an appropriate safety margin so you land on the right capacity — not just a rough estimate.

Where Servo Stabilizers Are Used

  • Homes and apartments — refrigerators, ACs, TVs, water pumps
  • Offices and retail — computers, servers, lighting, HVAC
  • Hospitals and labs — imaging and diagnostic equipment
  • Factories — CNC machines, motors, compressors, production lines

How Much kVA Servo Stabilizer Do You Actually Need?

Sizing a servo stabilizer correctly can feel tricky, and every manufacturer adds a 20–30% margin at the end regardless — so customers don't have to worry about future expansion. Once you see the actual math, it stops being intimidating.

kVA Isn't the Same Thing as What Your Machine "Uses"

Think about buying a kilogram of mangoes. What you actually want to eat is what's inside the fruit. But nobody sells you just the fruit — you pay for the whole kilogram, peel included. Motors work the same way electrically — part of the current goes toward useful work, and part goes toward magnetizing coils and other overhead that never shows up as output, but the stabilizer still has to supply it.

That combined total — useful work plus the extra — is kVA, not kW. This one distinction is probably responsible for more undersized stabilizers than any other mistake.

Converting kW to kVA

kVA = kW ÷ Power Factor

Defaulting to 1.0 because it's easier is exactly how stabilizers end up too small. When in doubt, 0.8 is a safe average to use across mixed loads.

Worked Example 1: A House With Multiple ACs

Connected Load Breakdown

LoadCalculationkW
6 × Split ACs (1.5 ton each)1.5 ton × 1.75 ÷ 0.8 × 6 units19.69
Refrigerator—0.30
Washing Machine—0.50
Water Pump (1 HP)1 HP × 1.75 ÷ 0.82.19
Lighting, fans, TV, kitchen—1.50

Total: 24.18 kW → ÷ 0.8 PF = 30.2 kVA → × 1.25 (25% margin) = 37.8 kVA

✓ Result: This house should size a 40 kVA stabilizer — higher than a rough guess, because it's built around real compressor and motor draw.

Worked Example 2: A Small Diagnostic Clinic

Connected Load Breakdown

LoadPower FactorkVA
X-ray Machine (6 kW)0.827.32
Ultrasound & monitoring gear (1.2 kW)0.901.33
Two AC units (3 kW)0.803.75
General lighting (0.8 kW)0.950.84

Total running load: 13.2 kVA. Clinics should use 30% margin due to imaging equipment — 13.2 × 1.30 = 17.2 kVA.

✓ Result: This clinic should land on a 20 kVA unit — enough headroom without paying for unused capacity.

Frequently Asked Questions

Do I really need a servo stabilizer for an inverter AC, or is it a waste of money?

A servo stabilizer's main job is to correct voltage fluctuations. A non-inverter AC has a heavy-duty compressor, while an inverter AC uses a much lower-capacity compressor that can tolerate low voltage, sometimes running even below 200V, down to around 180V. But if the voltage drops even further than that, the inverter compressor stops working too. And if the PCB gets damaged due to irregular voltage, that damage isn't covered under warranty. So the real question is: why not take that precaution beforehand? Precaution is better than cure — it's simply protecting yourself from future problems.

Why do two stabilizers of the same kVA rating from different brands cost so differently?

It largely depends on the brand. An unbranded or local manufacturer — producing units without following the routine testing required under IS standards — can offer the same kVA rating for a much lower price. A branded manufacturer has an in-house manufacturing unit, trained engineers, and proper quality checks. That process costs money, and it shows up in the price. But it also means you're protected — with a branded company you know who to hold accountable if something goes wrong.

Is a single large stabilizer for the whole house better than separate smaller ones per room?

Yes, a single unit on the main line is the best choice. It provides stable, fluctuation-free voltage to the whole house — including small appliances like LED bulbs, whose drivers can get damaged by high or low voltage fluctuations too. It's simply not practical to install a separate stabilizer for every small appliance in the house, but installing one on your main line protects everything downstream of it.

Digital display vs analog meter stabilizers — does it actually matter?

Yes, it matters a lot. At Servolink, we use an LCD display with a True RMS controlled card, which is far more responsive and accurate than an analog card. It shows real-time voltage and current readings without any delay — not just a rough needle reading that lags behind what's happening on the line.

Can I install a servo stabilizer myself, or does it need an electrician?

Installing a servo stabilizer is actually very easy — you just need proper guidance. Every stabilizer has two terminals: one input terminal where the incoming supply is connected, and one output terminal from which the stabilized voltage goes out to your load. If you're still unsure during installation, you can contact us — we're happy to guide you through it at no charge.

How do I calculate the right kVA rating for a servo voltage stabilizer?

Add up the running wattage of every appliance you want to protect, convert the total to kVA using the power factor, then apply a safety margin — typically 20–30%, higher where motor-driven or compressor loads make up a larger share of the total. The calculator above automates this calculation for you.

What safety margin should I use for a servo stabilizer?

A 20–25% margin is generally sufficient for electronic and lighting loads. Installations with a higher proportion of motors, compressors or pumps need a 30% margin to account for high starting (inrush) current.

What is the difference between single phase and three phase servo stabilizers?

Single phase servo stabilizers regulate a 230V supply and suit homes, shops and small offices. Three phase servo stabilizers regulate a 415V supply and are used for commercial buildings, factories and industrial machinery with higher connected loads.

Servo Voltage Stabilizer Sizing & Selection Sheet

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