Since 2007 we have built step up / step down transformers from 100VA to 10kVA and relay & servo voltage stabilizers from 0.5kVA to 1000kVA in Yueqing, Zhejiang — shipped to more than 20 countries with CE, RoHS and ISO 9001 documentation.
Send the input and output voltage, the kVA and the destination country standard — an engineer confirms the model within one working day.
Relay type 0.5–10kVA and servo type 5–120kVA stabilizers for 160–270V mains, single and three phase.
Step up / step down autotransformers from 100VA to 10kVA, plus custom windings for non-standard voltages and 60Hz markets.
Multi-stage charging with over-voltage, over-current and reverse-polarity protection for lead-acid and lithium banks.
Pure sine wave and modified sine wave inverters from 300W to 5.5kW, with MPPT solar charge controllers.
Yueqing Johsun Tec Electrical Co., Ltd has manufactured power conversion equipment in Zhejiang since 2007. The two core lines are step up / step down transformers from 100VA to 10kVA, and single- and three-phase voltage stabilizers from 0.5kVA to 1000kVA; inverters, battery chargers and frequency converters complete the range.
Winding, lamination stacking and final assembly all happen in our own plant, so a custom voltage combination is a drawing change rather than a new supply chain. That is why buyers come to us for 110V/220V export models, 60Hz variants for the Americas, and non-standard taps for panel builders. Every unit is function-tested before packing and ships with its routine test report; CE and RoHS declarations, ISO 9001 records and OEM branding are available on request.
Since 2007, we have specialized in voltage regulators and transformers. We offer full-spectrum customization.
ISO 9001:2008 managed and CE/FCC/IC certified. Our products undergo multiple rounds.
From industrial regulators to solar photovoltaic systems, we provide one-stop integrated power resources.
20+ years of expertise in Voltage Regulators, Transformers, and UPS for industrial safety.
Full customization from technical parameters to product appearance and sample development.
Sustainable Solar Photovoltaic systems, including inverters and panels for carbon neutrality.
Certified 15+ year supplier offering flexible trade terms (EXW/FOB/DDP) and remote technical guidance.
Our plant in the Xiangyang Industrial Zone covers winding, lamination stacking, vacuum varnish impregnation, assembly and final test under one roof. Copper or aluminium windings are wound to the drawing, the core is stacked and clamped, and each assembly is varnish-impregnated to lock the winding against vibration and moisture.
Before packing every unit goes through a turns-ratio check, a dielectric withstand (hi-pot) test and a full-load run. The routine test report for your serial numbers ships with the carton, which is what customs and tender reviewers usually ask for. Production capacity is roughly 3,000 units a month across transformers and stabilizers.
110/120V and 220/240V are stock tap positions; anything else is a winding change with a 15–25 day lead time.
One piece for standard models, 50 pieces for OEM branding or a custom panel.
CE and RoHS declarations, ISO 9001 records and a per-unit routine test report are supplied as PDF.
Most enquiries come down to three questions, and each one has a specific answer here rather than a brochure line.
ISO 9001:2015 quality management system, CE and RoHS declarations for EU shipments, and a routine test report issued per unit. Where a tender calls for it, we supply IEC 60076 and IEC 61558 test references, material certificates for the winding and core, and a factory acceptance test witnessed on video.
Documentation packs are issued as PDF within one working day of request.
Six situations account for most of the enquiries we quote as a transformer and stabilizer manufacturer. Pick the one closest to your job and go straight to the product family.
A 110V machine, tool or appliance running on a 220-240V site — the single most common reason buyers land on a DT/ST page.
A fixed control rail for PLC supplies, relays and sensors where the panel voltage differs from the plant supply.
Feeders that sag to 160-190V and climb past 250V. Relay stabilizers for general loads, servo for sensitive instruments.
Continuously adjustable 0-250V for sweep testing, burn-in racks, motor trim and relay pick-up checks.
Custom voltage, socket standard, front panel and packaging from 50 pcs, with CE / RoHS documentation.
Thirteen DT/ST capacities on three frames plus matching stabilizers, so one supplier covers 110V and 220V markets.
Ratings, protection, carton quantities and FOB bands on three pages each — the same documents our distributors file with their tenders. All four series are built in-house, not sourced.
Step up & step down autotransformer — ratings, cartons, FOB bands
Need the routine test report, a CE / RoHS declaration or an ISO 9001 reference for customs and tender submission? Ask for the documentation pack.
Give us these and an engineer replies, with the model, the price and the lead time:
Our products are trusted for their superior quality and reliability. Fill out the form and we will answer any questions you may have.
