Step Up Transformer 120V to 240V | STU Series
STU step up transformer for 120V to 240V. Automatic, copper wound, batch tested. Also steps 240V down to 120V. Overview This is our STU series set…
- Factory-direct pricing, no middleman markup
- Custom voltage, capacity and branding (OEM)
- MOQ from 10 pcs, production 15–25 days
- 12-month warranty with reliable support
STU step up transformer for 120V to 240V. Automatic, copper wound, batch tested. Also steps 240V down to 120V.
Overview
This is our STU series set for one specific job: taking a 120V supply and stepping it up to 240V for appliances and equipment that need it. It is the same automatic unit we ship worldwide, wound for the 120V to 240V combination, and it handles the conversion in both directions – so the same box that steps 120V up to 240V steps 240V down to 120V when you need it the other way. Everything is copper-wound and 100% tested in our own factory in Yueqing, China.
Who buys this? Mostly people who have moved equipment between voltage worlds – a 240V machine in a 120V country, or 120V gear in a 240V country – and want one reliable box to bridge the gap. Workshops, importers, appliance resellers and households all use the STU series for this. Because the unit selects the voltage automatically, there is no switch to flip and no room for wiring mistakes.
Key Specifications
| Parameter | Value |
|---|---|
| Input Voltage | 110V–120V ↔ 220V–240V (automatic) |
| Output Voltage | 110V–120V ↔ 220V–240V (automatic) |
| Capacity Range | 1000VA – 10000VA (STU series) |
| Frequency | 50Hz / 60Hz |
| Protection | Fuse / MCB protection |
| Output Sockets | Optional (US / EU / UK styles) |
| Winding | Copper, varnish-impregnated |
| Warranty | 12 months |
Features
- Automatic voltage selection – reads the input and switches itself, no manual tap.
- True bidirectional conversion – steps 120V up to 240V and 240V down to 120V.
- Real copper windings – runs cooler and holds regulation better under load.
- 50/60Hz rated – works on either mains frequency.
- Batch tested – every unit load-tested and recorded before shipping.
- OEM ready – your brand, your packaging, custom sockets.
Typical Applications
- 240V machines and tools running from a 120V supply
- US-market 120V equipment used in 240V countries
- Household appliances moved between voltage regions
- Workshop and import/resale stock for voltage conversion
Get a Factory-Direct Quote
MOQ 10 pcs · 15–25 days lead time · FOB Ningbo or Shanghai
More from This Range
ST-2000 Step Down Transformer2000VA step down with built-in RCD.
STU-3000 Step Up & Step Down Transformer3000W heavy-duty bidirectional converter.
STU-5000 Step Up & Step Down Transformer5000W automatic voltage converter.
Frequently Asked Questions
Can the STU series step 120V up to 240V automatically?
Yes. The STU series selects the input voltage automatically and converts between 110-120V and 220-240V in both directions. Feed it 120V and it outputs 240V; feed it 240V and it outputs 120V. No switch to set.
What size STU transformer do I need for my 240V appliance?
Check the appliance wattage, add 30% margin, and for motor loads double it. A 2000W machine wants at least a 3000VA unit. The STU range covers 1000VA to 10000VA.
Does the STU series work on 50Hz and 60Hz?
Yes, every STU unit is rated for both 50Hz and 60Hz, so the same transformer works across regions without modification.
Can I order STU transformers with my own brand?
Yes, OEM branding from MOQ 10 pcs per model, with custom sockets, packaging and your label on the case.
What is the MOQ and lead time?
MOQ is 10 pcs per model, production takes 15-25 days, FOB Ningbo or Shanghai, with CE / RoHS documents.