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    4 kVA Isolation Transformer, Single Phase, 220V to 110V

    5 out of 5 based on 3 reviews | Write a review
    Single phase dry isolation transformer features 4 kVA power capacity, 50Hz/ 60Hz frequency, step down 220V primary voltage to 110V secondary voltage, 110V to 220V step up version or other voltages can be customized. Optional enameled copper wire or aluminum wire, IP20 enclosure type or open type.
    30-day Returns
    Delivery date: 10-20 days

    4 kVA dry type isolation transformer for sale at affordable price. It is designed to step up/down the AC single phase voltage between 220 volt and 110 volt that with frequency 50Hz/60Hz. Customizable 1-phase isolation transformer works with superior performance and lower energy losses.
    Isolation transformers serve as secure power sources and are commonly employed in machine repair and maintenance to provide protection, prevent damage from lightning, and filter out electrical disturbances. Here is a demonstration video of a single phase isolation transformer.


    Single phase isolation transformer has a reasonable design, is safe and reliable, and has no waveform distortion, completely insulates the electrical between the primary and secondary sides and isolates the circuit. It is widely used in transportation, construction sites, printing, CNC machine tools, docks, precision equipment, industrial mining enterprises and tunnels for power transmission and distribution to solve voltage conversion problems.

    Basic Specifications

    • Model: ATO-DG4kVA
    • Capacity: 4kVA
    • Phase: Single phase
    • Winding Material: Aluminum/Copper wire (Optional)
    • Frequency: 50Hz/60Hz
    • Work Efficiency: ≥95%
    • Primary Voltage: 220V AC (optional: 110V/ 120V/ 208V/ 230V/ 240V)
    • Secondary Voltage: 110V AC (optional: 120V/ 208V/ 220V/ 230V/ 240V)
    • Weight: 50 kg

    Technical Specifications

    • Cooling Mode: Natural or air cooling
    • Insulation Resistance: ≥50 MΩ
    • Electrical Strength: 2000V AC/1 min
    • Noise: ≤35dB (1 meter)
    • Insulation Grade: Grade B (130℃), Grade F (155℃), Grade H (180℃)
    • Overload Capacity: Allow more than 1.2 times rated load to work for up to 1 hour
    • Induced Overvoltage Withstand Test: 125Hz/800V/min
    • Impedance Voltage: About 6%
    • Total Losses: 10%
    • Certification: CE, ISO
    • Temperature: -15℃~+45℃
    • Enclosure Protection Grade: IP20
    • Warranty: 12 months


    • Heat dissipation holes and fans: The enclosure is a multi-hole design, the back of the transformer installed cooling fan, can be strong and effective heat dissipation, reduce the temperature of the machine, to better protect the internal components.
    • Two-color indicator: Input and output using LCD digital display meter, equipped with indicators to accurately display the voltage when working state.
    • High temperature resistant enameled wire: High temperature resistance up to 180℃, good insulation and not easy to aging, prolong the service life of the machine.
    • Oriented silicon steel sheet: Cold rolled oriented silicon steel sheet is used, which has the advantages of good heat dissipation coefficient, low core loss and good magnetization characteristics.
    • Long-term continuous work: With a wide range of applicable loads, can withstand transient overload, can work continuously for a long time.
    • Universal casters: Isolation transformer with four universal wheels, easy to move, can rotate 360 degrees, more energy-saving when pushing.
    • Enclosure: With strong enclosure to effectively prevent dust and protect the internal transformer.


    1. Transformer can only convert voltage and CANNOT convert frequency.
    2. Transformer CANNOT convert single phase to 3 phase voltage.
    3. Support voltage customization, various specifications customization.

    800 VA-15 kVA single phase isolation transformer schematic diagram


    Single Phase Isolation Transformer Details

    Tips: Faults of Single Phase Step UP/Down Isolation Transformer

    Internal faults
    Internal faults of a single phase step up & step down isolation transformer include interphase short circuit, turn-to-turn short circuit of the winding and grounded short circuit of earth neutral system and winding grounding system. These faults are quite serious, because the high temperature arc generated by short-circuit current will not only burn the iron core of winding insulation box, but also makes the insulating material and isolation transformer oil to decompose, thus producing a large amount of gas, which might lead to local deformation and break of transformer oil tank, or even explosion hazard. Therefore, when an internal fault occurs in the transformer, the transformer shall be removed quickly.

    External faults
    External faults of a single phase isolation transformer mainly include the interphase short circuit and grounded short circuit occurring on the bushing shell and outgoing line of the transformer. In case of such a fault, the transformer should also be rapidly removed, so as to minimize the impact of short circuit current on the transformer.


    1-phase isolation transformer dimension

    Aluminium Wire Transformer Size

    Without Enclosure: a*b*c=210*230*230mm

    Mouting Size: D*E=150*170mm (aperture: 18*8mm)

    With Enclosure: A*B*C=300*440*500mm

    Copper Wire Transformer Size

    Without Enclosure: a*b*c=192*210*220mm

    Mouting Size: D*E=140*160mm (aperture: 17*8mm)

    With Enclosure: A*B*C=300*440*500mm


    360 Days warranty

    Thank you for buying industrial automation products on, all products sold by ATO and the partner cover a 360-days-warranty, effective from the date of receiving the products.

    What is covered?

    ATO is responsible for providing free spare parts, free technical support to assist the customer to repair the defective products until the problem is solved.

    What is not covered?

    • Product purchased from anyone other than ATO store or a ATO authorized reseller.
    • Expendable parts.
    • Routine cleaning or normal cosmetic and mechanical wear.
    • Damage from misuse, abuse or neglect.
    • Damage from use of parts other than ATO approved.
    • Damage from use outside the product’s usage or storage parameters.
    • Damage from use of parts not sold by ATO.
    • Damage from modification or incorporation into other products.
    • Damage from repair or replacement of warranted parts by a service provider other than a ATO authorized service provider.
    • Damage caused by the application environment not meeting the product usage requirements and the failure to perform preventive maintenance.
    Existing reviews of 4 kVA Isolation Transformer, Single Phase, 220V to 110V
    Can you make these for us?
    We are using a buck boost transformer in equipment we are manufacturing. We are using it to generate the 12V at 250A by using both outputs in parallel. We are in the process of redesigning this equipment and we would like a smaller form factor that your toroid transformer would allow.  Our current need is for 25 pcs. Can you make these for us?
    From: Bruce | Date: 27/07/2022
    Was this review helpful? Yes No (0/0)
    ATO Responded
    Ok, just to clarify, below is a 3000VA toroidal transformer, not 3000KVA, right?
    Please let us know what the input is and output voltage of the toroidal transformer? And what are your requirements for the size of the toroidal transformer?
    Information about 4kW isolation transformer
    I'm led to believe you can supply transformers to the United Kingdom. I'm looking at the following item:
    Part Number: SKU: ATO-T-DG4KVA
    Winding material: Copper wire
    Primary voltage: 230V ac
    Secondary voltage: 110V ac
    Transformer type: Protected type
    Mounted option: Moveable wheels
    Cost: $999.46
    Can you tell me what the delivery schedule and cost for shipping to the UK will be please? I assume if I order via your website the international shipping charge will be payable at that point?
    One final question, I'm looking to run 2 pieces of equipment from this transformer. Does the secondary winding output facilitate for 2 pieces of equipment 2 output terminals).
    From: Ronwood | Date: 31/08/2021
    Was this review helpful? Yes No (0/0)
    ATO Responded
    1. Yes, you can order via our website, and the international shipping charge will be payable at that point. Order by credit card on:
    2. Yes, you can run 2 pieces of equipment from this transformer. As the secondary winding output facilitate for 2 pieces of equipment or more, just do Not go above transformer max power capacity "4kVA".
    Would like to buy your 4kVA isolation transformer
    For your 4kVA single phase isolation transformer, does it work safely based on  /- 4% input voltage tolerance "supply"?
    From: Robert Alcala | Date: 28/07/2020
    Was this review helpful? Yes No (0/0)
    ATO Responded
    Yes, its okay up to 5% supply voltage varaiation tolerance.
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