Product Range
Variable Transformer (Variac) Models We Build
American Style Variac 500VACompact variac for labs and repair benches, 0-260V dial.
American Style Variac 1KVA1KVA adjustable variac for testing and calibration.
American Style Variac 2KVA2KVA variac with smooth 0-260V output for workshops.
American Style Variac 3000VA3KVA heavy-duty variac for industrial test setups.
TDGC3-500W Variable Transformer500W single phase digital variac with LCD, 0-300V adjustable output.TDGC2J-1KVA Digital Variable Transformer1000VA with LCD voltmeter, 0-300V output.
TSGC2-3KVA Three Phase Variable Transformer3000VA three phase variac, 0-430V adjustable.TSGC2-6KVA Three Phase Variable Transformer6000VA three phase variac for industrial motor testing.
TDGC2 AC Single Phase Variable Transformer500VA-30KVA contact type manual voltage regulator, 220V to 0-250V.
A variable transformer — a variac, as most buyers call it — does one thing no fixed transformer can: it lets you dial the output voltage to any value between zero and 260V and hold it there. Turn the knob, watch the meter, stop where you need to. Laboratories use them to test power supplies, workshops use them to soft-start motors, plating shops use them to control a bath heater, and repair benches use them to bring old equipment up slowly. That single ability is why the variac has stayed in production for almost a century.
Overview
What This Series Does
A variable transformer (variac) provides continuously adjustable AC output voltage from 0 to 260V single phase, or 0 to 430V three phase. Because the output is tapped directly off a toroidal winding by a carbon brush, the waveform stays a clean sine wave — no chopping, no switching noise, no stepped output like you get from a cheap electronic regulator. That is what makes a variac suitable for calibration work and for equipment that is sensitive to a distorted supply.
Used in laboratories and universities, on equipment test and repair benches, for motor testing and soft-start, and in plating, heating and lamp-testing applications worldwide.
Model comparison: which variac fits which job
Nine models, three series. The table below is the short version of how we match a buyer to a unit — capacity first, then phase, then whether you need a digital readout.
| Series / model | Capacity | Phase | Output | Meter | Typical use |
|---|---|---|---|---|---|
| TDGC2 / TDGC2J | 500VA – 3kVA | Single | 0–250V / 0–260V | Analog or LCD | Lab benches, repair, calibration |
| TDGC2 (AC) | 500VA – 30kVA | Single | 0–250V / 0–300V | Analog or LCD | General purpose, OEM panels |
| TDGC3-500W | 500W | Single | 0–300V | LCD digital | Precision bench work, 2A fuse |
| TDGC2J-1KVA | 1kVA | Single | 0–300V | LCD digital | Test benches needing exact readout |
| TSGC2-3KVA | 3kVA | Three | 0–430V | Analog or LCD | Three-phase motor testing, small panels |
| TSGC2-6KVA | 6kVA | Three | 0–430V | Analog or LCD | Larger motors, production test benches |
| TSGC2 (to order) | up to 30kVA | Three | 0–430V / 380V / 415V | Analog or LCD | Plant commissioning, export builds |
All ratings are continuous at full output voltage. Above approximately 10kVA single phase we would normally steer you to the three-phase TSGC2 series instead of a larger single-phase unit.
Specifications
Key Specifications
| Output Range | 0–260V or 0–130V (single phase) / 0–430V (three phase) |
| Capacity | 500VA – 30KVA single phase / 3KVA – 30KVA three phase |
| Frequency | 50Hz / 60Hz |
| Display | Analog voltmeter or digital LCD (voltage + current) |
| Output Waveform | Pure sine wave, stepless adjustment |
| Cooling | Natural convection; fan-assisted on larger ratings |
| Socket Standard | US style as standard; EU / UK / AU or bare terminals on request |
| Warranty | 12 months from delivery |
How a Variac is different
Unlike a fixed transformer with one output, a variac has a carbon brush that rides along the exposed winding. As you turn the knob, the brush taps the winding at a different point and the output voltage changes continuously — that is why it is called stepless. Because it is still a transformer, it isolates the load and keeps a clean sine wave, which matters when you are testing equipment that is sensitive to the chopped waveforms some cheap regulators produce.
Our range at a glance
- Single-phase TDGC2 series — 500VA up to 30KVA, 0-250V or 0-300V output, the standard for labs and workshops.
- Digital display models — TDGC2J and TDGC3 with LCD readout showing output voltage and current, handy for test benches.
- Three-phase TSGC2 series — 3KVA to 6KVA and up, 0-430V output, for motor testing and three-phase equipment.
- Socket options — US style sockets as standard; EU, UK or AU available, or bare terminals for panel mounting.
Choosing the right rating
Size a variac the way you size any transformer: load plus headroom. For continuous duty, pick a rating at least 30% above your load. If the load has a motor or a transformer inside it, allow more — inrush will be several times the running current. One thing buyers often miss: the knob position matters. A variac rated 2KVA delivers that at full output voltage; at lower knob positions the output current limit stays about the same, so you do not gain much headroom by turning it down.
Three Phase
Three Phase Variac (TSGC2 Series)
A single-phase variac cannot drive three-phase equipment, and that is the request we get most often from industrial buyers. The TSGC2 series is our three-phase answer: three ganged brush assemblies on a common shaft, so one knob adjusts all three phases together and the output stays balanced. That balance is the whole point — if the phases drift apart, motors run hot and test readings stop meaning anything.
- TSGC2-3KVA — 3000VA, 0-430V output, the usual choice for three-phase motor testing and small control panels.
- TSGC2-6KVA — 6000VA, 0-430V output, for larger motors, workshops and production test benches.
- Larger ratings — we wind three-phase units up to 30KVA to order, including 380V and 415V line voltages common in the Middle East and Africa.
Typical three-phase variac jobs: running a three-phase motor at reduced speed during commissioning, testing three-phase power supplies and inverters, calibrating panel meters, and slowly energising rebuilt equipment so a fault shows up before full voltage does. If you are not sure whether your application needs single or three phase, tell us what you are testing and we will confirm.
Pricing
Variac Price & Ordering
Buyers searching for a variac price usually get one of two answers: a number that turns out to be for a model that will not do the job, or a request for your email before anyone will talk. We do neither — here is the actual starting price for the smallest unit, and the rules that move it up as the rating grows.
| Starting price | US$18 per unit — TDGC2-500VA single phase, 0–250V input / 0–300V output, analog meter, copper winding, FOB Ningbo or Shanghai, MOQ 1 pc for stock units, 10 pcs for custom voltage |
| What US$18 covers | Copper wound toroidal autotransformer, brush arm aligned and torqued at the factory, no-load and load test before packing, 12-month warranty, standard export carton |
| Capacity above 500VA | Price scales with copper and core weight — a 3KVA unit costs roughly three to four times a 500VA unit, with 1KVA and 2KVA in between. Send the rating and we quote it exactly |
| Single or three phase | Three-phase units carry three windings and cost materially more than the same VA single phase |
| Analog or LCD | Digital LCD metering adds a small premium per unit over the analog version |
| Order quantity | MOQ 1 pc for stock units, 10 pcs per model for custom voltage; container-load volumes move the unit price down, and OEM branding is available from MOQ |
| Lead time | 15–25 days production, plus shipping |
| Payment | T/T 30% deposit and 70% against the B/L copy, L/C at sight, or Trade Assurance |
| Other Incoterms | FOB Ningbo or Shanghai is standard; CIF and door delivery on request |
Why US$18 is possible: we wind the coils in our own workshop in Yueqing, buy copper by the tonne, and ship from the factory floor — there is no trading company standing between you and the machine. The same 500VA unit therefore leaves here at a price a distributor cannot match, and every unit is still load tested before it is packed.
When you compare suppliers, ask all of them for the same three things: copper winding, load test before shipment, and the actual VA rating at full output voltage. Those three answers separate a variac that lasts ten years from one that fails in the first season.
How to order a variac for sale
Every rating above 500VA is quoted to order, so the sequence from enquiry to delivery is short and does not begin with a registration form.
- Send three things — the capacity, the input and output voltage range, and the socket standard your market uses.
- Get an FOB price within 24 hours — with a production date and a carton dimension, so you can cost the freight before you commit.
- Confirm with a deposit — 30% by T/T and the balance against the B/L copy; L/C at sight and Trade Assurance are accepted too.
- Test a sample if you need to — a single unit of any rating can ship ahead of the production run so it reaches your own bench first.
- Production and inspection — 15 to 25 days, with load test records available before shipment and third-party inspection welcome.
FOB price, landed cost, and what changes by market
US$18 is an FOB price. It covers the unit and its export carton and stops at the port, which means three costs are added on the way to your door: freight, duty and local handling. For a buyer in the Philippines the usual route is Ningbo or Shanghai to Manila, LCL for a first order and FCL once volume justifies it; the same cartons serve the Gulf, Africa and South America through the same two ports. Ask us for the carton weight and CBM of the rating you need and your forwarder can cost the rest — or send us your forwarder’s details and we will hand the dimensions over directly.
Two details make the landed cost easier to plan. Every rating ships in a carton with the model number, VA rating and voltage range printed on the outside, so customs classification does not depend on guesswork. And several ratings can be consolidated into one shipment — a mixed pallet of 500VA and 1KVA units costs less per unit in freight than two separate orders.
Why buy from the factory
We have been winding variacs in Yueqing for years, and build quality is the difference between a tool that lasts a decade and one that carbon-fouls in a year. Every unit gets a no-load and load test before packing, the brush arm is aligned and torqued at the factory, and we stand behind it with a 12-month warranty. MOQ is 1 piece for stock units, 10 pieces for custom voltage, lead time 15 to 25 days, FOB Ningbo or Shanghai — and we can print your brand on the case if you are reselling.
Applications
Applications & Benefits
- Laboratories and universities for experiments and calibration
- Equipment repair benches and appliance testing
- Motor soft-start during test runs
- Lamp brightness and heater testing
- Plating and surface-treatment bath control
- Three-phase equipment commissioning and verification
FAQ
Questions Customers Ask Us
What is the warranty?
12 months from delivery on every unit.
What is the minimum order quantity?
From 1 pc on stock 110V/220V units (10 pcs per spec for custom voltage). OEM labels are free with no MOQ.
Can you customize voltage and capacity?
Yes — any voltage combination, capacity and enclosure is built to order.
What is the typical lead time?
Stock units ship in 3–5 working days; made-to-order units take 15–25 days production, plus shipping to your country.
What is the price of a variac?
It depends on capacity, single or three phase, and metering. Send us your capacity and quantity and we return an FOB price within 24 hours.
Do you make three-phase variacs?
Yes. The TSGC2 series covers 3KVA to 6KVA and up with 0-430V output, and larger ratings are wound to order.
What is the difference between a variac and a voltage stabilizer?
A variac is manually adjustable — you set the voltage. A stabilizer holds a fixed voltage automatically. They solve different problems; we build both and will tell you which one your case needs.
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