What is SG Low-Voltage Transformer？

2026-07-24 0 Leave me a message

Anyone who's bought imported equipment knows the problem: the nameplate says one voltage, but your workshop has another. Voltage mismatch means the equipment can't run.

The SG threephase lowvoltage transformer is built to solve exactly that problem.

It's a threephase drytype isolation transformer. Feed it your local supply—380V, 400V, 415V—and it can give you whatever the equipment needs: 220V, 200V, 110V, 36V, you name it. At the same time, it completely isolates the input from the output—so grid noise, harmonics, and surges stop right there.

In plain language: it converts the voltage to what you need and keeps the interference out.

Where Does SG threephase lowvoltage transformer Fit?

The SG series works in pretty much any lowvoltage threephase application that needs voltage conversion and electrical isolation.

Here's where you'll find them:

Application	Why It's Used
Imported equipment	Your local grid doesn't match what the machine needs? The SG converts it. 380V to 220V and 380V to 200V are the most common requests
Machine tools and automation	CNC machines, machining centres, and all kinds of industrial equipment. One transformer handles both control and power circuits
Lighting and indicators	Workshop lighting, machine indicator lights, local illumination
Rectifier power supplies	Frontend power for electroplating, electrolysis, and DC drive equipment
Critical facilities	Power plants, data centres, medical equipment, communication systems
Highrise buildings and public spaces	Office buildings, shopping centres, museums—indoor locations with strict fire safety requirements

The SG series is also widely used in mining and industrial enterprises, airports, and anywhere with high safety and fire protection requirements.

In short: wherever you need to change voltage or keep interference out of a lowvoltage threephase system, the SG fits.

What Makes SG threephase lowvoltage transformer Different?

Drytype construction, no oil. No leaks, no fire risk. You can install it indoors, in a cabinet, right next to the equipment—without worrying about oil spills. The insulation materials are flameretardant and selfextinguishing, and they don't release toxic gases when heated.

Isolation design. Primary and secondary windings are completely separate. Grid noise, harmonics, and surges stop at the transformer—they don't reach your equipment. Control circuits stay clean, equipment stays stable.

Low losses, high efficiency. With a wellbuilt SG transformer, noload loss can be under 0.8%, and fullload efficiency can exceed 97.5%. That means less wasted electricity and lower operating costs.

Low noise, low partial discharge. Vacuumcast windings mean no voids or bubbles in the insulation—partial discharge below 5pc. Running noise is typically under 65dB. It runs quiet enough that you barely notice it's there.

Pure copper windings, Class H insulation available. Good conductivity, low heat generation. Class H (180°C) insulation means it can handle continuous heavy loads without cooking itself.

Customisable. Input/output voltage, connection group, tap positions (±5% or ±10%), winding capacity distribution, enclosure—all can be built to your requirements. Coils can be epoxycast for extra protection against moisture, oil, and water.

Open or protected enclosure. IP00 (open) or IP20 (protected) are standard; higher ratings available on request.

Built for continuous operation. SG transformers can handle widely varying loads, bear instant overloads, and run continuously for long periods.

SG Low-Voltage Dry-Type Transformer

How to Pick the Right One

Three things matter most: capacity, voltage, and installation environment.

Step 1 — Determine your load

Add up the total power of everything you're connecting, then leave about 2030% margin. Motors and compressors draw high startup current—size generously. SG capacities range from under 1kVA up to 2500kVA.

Step 2 — Specify input and output voltages

Parameter	Options
Input voltage	200V, 220V, 380V, 400V, 660V, 690V, 800V, 1140V—whatever your site supplies
Output voltage	690V, 400V, 380V, 220V, 110V, 36V—whatever your equipment needs
Connection group	Y/yn0, Y/d, D/y, D/d—choose what fits your system
Taps	±5% or ±10% for line voltage adjustment

Step 3 — Consider the installation environment

Condition	Requirement
Altitude	≤2000m standard
Ambient temperature	-5°C to +40°C (indoor); -30°C available for outdoor
Humidity	≤90% at +25°C
Atmosphere	No corrosive gases, no conductive dust, no explosive substances
Vibration	No severe vibration or shock

Enclosure or not? If it's going inside a cabinet, open type (IP00) works. If it's freestanding, add a protected enclosure (IP20 or higher).

Final Thoughts

The SG lowvoltage drytype transformer isn't flashy. It doesn't connect to WiFi, doesn't have a touchscreen, doesn't make headlines.

What it does is straightforward: it gets the voltage right and keeps the interference out.

For factories, workshops, and laboratories that have been wrestling with voltage mismatches and equipment glitches, the difference is immediate. Equipment starts working. Interference disappears. Production doesn't stop.

It's not the star of the show. It's the stage that makes the show possible.