Convertisseur de tension AC vers DC Série STU STU 100VA-5000VA

Les convertisseurs de tension CA/CC sont fournis par un fabricant de confiance et une usine OEM/ODM, qui propose de faibles quantités, des prix de gros et des solutions personnalisées pour les applications industrielles et commerciales.

  • Model range: STU-100 to STU-5000 (11 models)
  • Capacité nominale : 100VA - 5,000VA
  • Tension d'entrée : 110 / 120 / 220 / 240V, rotary selector
  • Output voltage: 110-120V or 220-240V + 5A USB outlet
  • Phases: Single phase
  • Fréquence : 50 / 60 Hz
  • Protection: Input fuse + MCB, ON/OFF switch
  • Conversion: Passive AC-AC, bidirectional, no switching stage
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Description

STU series voltage converter 100VA–5000VA

  • Single or twin output sockets to order
  • Carrying handle up to the 3000VA frame
  • Rotary input voltage selector
  • ON/OFF switch with indicator
  • Fuse and MCB protection
  • Warranty: one year from the date of delivery

Fonctions

  • Bidirectional conversion across the full 110–120V and 220–240V mains range.
  • Primary tap selected by hand for the supply at the installation point.
  • Standard positions 110V, 120V, 220V and 240V, with bespoke windings available.
  • Secondary output at 110/120V or 220/240V, plus a 5A USB outlet on the case.
  • Typical duty: control circuits, automation panels, sensors and small drive systems.
Modèle Capacité Taille de l'emballage (cm) Qté/Colis
STU-100 100W 41.5×27×38 12PCS
STU-200 200W 41.5×27×38 12PCS
STU-300 300W 48×29×41 12PCS
STU-500 500W 48×29×41 12PCS
STU-750 750W 48×29×41 12PCS
STU-1000 1000W 49.5×33×21 2PCS
STU-1500 1500W 49.5×33×21 2PCS
STU-2000 2000w 49.5×33×21 2PCS
STU-3000 3000w 54.5×33×24.5 2PCS
STU-4000 4000w 54.5×33×24.5 2PCS
STU-5000 5000W 54.5×33×24.5 2PCS
STU-7500 7500W 42.5×33×28 1PCS
STU-10000 10000W 42.5×33×28 1PCS

The STU series is a passive AC-to-AC step up and step down converter: a single-phase transformer with selectable 110 / 120 / 220 / 240V input taps, an output at 110-120V or 220-240V, and an auxiliary 5A USB outlet on the case. Because there is no switching stage, it puts no high-frequency ripple onto the supply and radiates very little, which is why it is used inside automation panels next to PLC power supplies, relays, load cells and analogue instrumentation. Models run from 100VA to 5,000VA on three enclosure frames.

Typical duty is control rails, sensor supplies, HVAC control cabinets, telecom and CCTV enclosures and small drive systems. It is not a DC power supply: where a panel also needs a regulated DC rail, specify a separate DIN-rail unit alongside it. The passive design tolerates short-circuit surges and adds no harmonic distortion, so a fault on the load does not put switching noise back onto the panel supply.

The STU series is a passive AC-to-AC step up and step down converter: a single-phase transformer with selectable 110 / 120 / 220 / 240V input taps, an output at 110-120V or 220-240V, and an auxiliary 5A USB outlet on the case. Because there is no switching stage, it puts no high-frequency ripple onto the supply and radiates very little, which is why it is used inside automation panels next to PLC power supplies, relays, load cells and analogue instrumentation. Models run from 100VA to 5,000VA on three enclosure frames.

■ How to Choose This Transformer

Panels rarely draw a steady load: a cabinet might idle at 80W and peak at 600W when several contactors pull in together. Size for the peak plus a margin, and remember that the transformer sees that peak as a step change rather than a gradual ramp. Where the peak is driven by inductive devices, include the holding current of every coil that can be energised at the same time. The 100VA to 1000VA frames cover electronics and small control circuits; 1500VA upward is for panel supply and light machinery.

Three items to settle before ordering:

  • the simultaneous peak load, including coil holding currents;
  • the conversion direction and the mains voltage at the panel;
  • the socket standard and whether the unit will be plugged in or wired to terminals.

■ Panel Design with a Passive Transformer

Engineers choose a magnetic converter rather than a switching supply for one main reason: electrical quietness. A passive design puts no high-frequency ripple onto the supply and radiates very little, so it can share a cabinet with analogue instrumentation, load cells and signal wiring without an EMC filter. The trade-off is physical size and weight per watt. Serviceability is straightforward: fuses are accessible without removing the unit, and there are no fans or electrolytic capacitors to replace.

■ Pricing, Ordering & Quality Assurance

Step Up & Step Down Transformer Price Range (100VA–10KVA)

Pricing for the DT/ST series depends on capacity, the input/output voltage combination you need, socket type, and whether a voltage selector or MCB protection is fitted. The table below gives indicative FOB levels so you can budget before requesting a firm quotation.

Modèle Capacité Input / Output Voltage Application type Indicative FOB Price (per pc)*
ST/DT-100 100VA 110V ↔ 220V selectable Small electronics, chargers, control circuits US$ 10–15
ST/DT-200 200VA 110V ↔ 220V selectable Bench instruments, small appliances US$ 11–16
ST/DT-300 300VA 110V ↔ 220V selectable Audio equipment, laboratory benches US$ 12-18
ST/DT-500 500VA 110V ↔ 220V selectable Refrigeration units, printers, POS systems US$ 12-20
ST/DT-1000 1000VA 110V ↔ 220V selectable Power tools, kitchen equipment, single machines US$ 21-30
ST/DT-1500 1500VA 110V ↔ 220V selectable Motor-driven machines, imported appliances US$ 23-35
ST/DT-2000 2000VA 110V ↔ 220V selectable Compressors, welders, multi-outlet benches US$ 25-37
ST/DT-3000 3000VA 110V ↔ 220V selectable Small production lines, test rigs US$ 33-43
ST/DT-5000 5000VA 110V ↔ 220V selectable HVAC, industrial machinery US$ 52-62
ST/DT-7500 7500VA 110V ↔ 220V selectable Heavy workshop loads US$ 75-87
ST/DT-10000 10000VA 110V ↔ 220V selectable CNC equipment, whole-panel supply US$ 85-112

* Indicative FOB Ningbo/Shanghai, standard configuration, based on 50 pcs per size. Not a formal offer — final price depends on your voltage combination, socket standard, enclosure and order quantity.

  1. The efficiency of the DT/ST series is 80%. For equipment with motors or compressors, the starting current will multiply — always reserve adequate power margin.
  2. Pure resistive / electronic loads: choose a transformer with capacity ≥ 1.5× the equipment rated power.
  3. Inductive loads such as motors and compressors: choose a transformer with capacity ≥ 2.5–3× the equipment rated power.
  4. This table is for reference only. Confirm the final solution according to the rated power and duty cycle shown on your equipment nameplate.

MOQ, Lead Time & Ordering Information

Minimum Order Quantity (MOQ) 1 PC for standard DT models. Smaller trial orders can be discussed for first-time buyers.
Custom / OEM orders 50 PCS for custom voltage, custom socket layout, branded front panel or non-standard capacity.
Sample 1-2 pcs sample available for verified buyers. Sample lead time 3-5 working days.
Délai d'exécution 10-20 working days for standard models after order confirmation and deposit; 15-25 working days for OEM or custom configurations.
Emballage Export carton with foam. 1/2/6 pcs per carton – see the packing table above.
Payment terms 100% TT IN ADVANCE FOR RETAIL/SAMPLE; 30% TT IN ADVANCE AS DEPOSIT, THE BALANCE BEFORE SHIPMENT.
Shipping FOB Ningbo. CIF and door-to-door available on request.
Garantie 12 MONTHS FROM DELIVERY DATE

Certifications & Quality Assurance

DT/ST series step up and step down transformers are produced under our ISO 9001 quality management system, and every unit is 100% function-tested before packing.

CE Certified  |  RoHS Compliant  |  IEC Tested  |  ISO 9001  |  EMC Tested  |  12-Month Warranty

Certificates and routine test reports can be issued as PDF on request, for customs clearance, tender submissions or distributor onboarding.

■ FAQ

Is this an AC to DC converter?

The STU range is an isolating AC step up and step down transformer, catalogued on this site for control and instrumentation duty. If your load is genuinely DC, tell us the required output and we will confirm the correct product from the range.

How much margin should I leave on the rating?

At least 30 %. A passive transformer run at 70 % of its rating stays cooler, produces less noise and lasts longer than one run at its limit, particularly inside a closed cabinet.

Will it interfere with instrumentation on the same panel?

No. Being a passive magnetic device with no switching stage, it does not generate high-frequency noise and can be installed alongside analogue signal wiring.

What is the delivery time for a custom voltage?

15–25 working days for custom configurations against a minimum of fifty pieces per specification; standard models ship in 10–20 working days.

Typical applications for the STU series

Where buyers actually put this frame — matched to the markets and duty cycles we ship into.

  • Automation and PLC panelsA fixed 110V or 220V control rail for PLC power supplies, relays and interface boards.
  • Sensors and instrumentationThe passive design puts no high-frequency ripple on the supply, so analogue signals stay clean.
  • HVAC control cabinetsDamper actuators, controllers and thermostats imported at a different mains voltage.
  • Small drive and pump systemsFeed a single VFD or soft starter where the panel voltage differs from the plant supply.
  • Telecom and CCTV enclosuresCamera and recorder kits supplied at 110V into a 220V building.
  • Workshop test benchesUSB outlet on the case for programming laptops and handheld instruments.

Full specification — STU series step up & step down converter

Every rating below is what we build to at the factory. Confirm your voltage combination and country standard when you enquire.

Model range STU-100, 200, 300, 500, 750, 1,000, 1,500, 2,000, 3,000, 4,000, 5,000
Capacité nominale 100VA to 5,000VA
Number of phases Single phase
Tension d'entrée 110 / 120 / 220 / 240V standard tap positions, selected by rotary switch
Tension de sortie 110-120V or 220-240V, plus a 5A USB outlet on the case
Fréquence 50 / 60 Hz
Conversion Bidirectional AC-AC, passive transformer, no switching stage
Protection de l'environnement Input fuse + MCB, ON/OFF switch with indicator
Refroidissement Natural air convection, electrically quiet for instrumentation cabinets
Température de fonctionnement 0°C to +40°C
Enceinte Metal case with carrying handle up to the 3,000VA frame; single or twin output sockets to order
Conformité CE, RoHS; produced under ISO 9001 quality system
Garantie 12 months from delivery date

STU is a passive AC-AC converter, not an AC-to-DC power supply — the USB outlet is an auxiliary 5V tap only.

Download & documentation

Send these to your engineering or procurement team before you shortlist a supplier.

Get a firm quotation in one working day

Tell us four things and we can quote without a second round of questions:

  • Input voltage and output voltage (and the country standard)
  • Required capacity in VA or the load list in watts
  • Quantity for the first order and the annual volume
  • Whether you need OEM branding, a custom socket or a non-standard voltage

Engineering reply, not a sales auto-responder. Samples of 1-2 pcs available for verified buyers.

Talk to the factory directly

Related pages

FAQ

Is the STU series an AC to DC converter?

No. The STU series is a passive AC-to-AC step up and step down transformer. The output is a clean sine wave at the selected voltage, and the 5A USB outlet on the case is an auxiliary 5V tap for small devices, not a DC power supply. Where a panel also needs a regulated DC rail, specify a separate DIN-rail power supply.

What margin should I leave on the rating?

Add the running load in VA and apply 1.3x where motors or compressors are involved. For resistive and electronic loads, 1.15x is normally enough. Passive transformers tolerate short overloads well but run warmer, so the margin is about service life rather than immediate failure.

Can it sit inside a PLC cabinet without interference?

Yes. Because there is no switching stage, the STU series puts no high-frequency ripple on the supply and radiates very little, which is why it is used alongside analogue instrumentation and load cells. Keep the usual clearance for convection and route signal cables away from the winding.

Demande de devis

Indiquez-nous vos spécifications, la quantité souhaitée ou le cas d'utilisation, et nous vous proposerons un devis sur mesure.

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