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  • New item   -83.67€Single-phase autotransformer for fan speed control | Sentera Controls | ATR-1100L25
    New item   -83.67€Single-phase autotransformer for fan speed control | Sentera Controls | ATR-1100L25 1
    New item   -83.67€Single-phase autotransformer for fan speed control | Sentera Controls | ATR-1100L25 2

    Single-phase autotransformer for fan speed control | Sentera Controls | ATR-1100L25

    Code: ATR-1100L25
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  • Product description

    Single-phase autotransformer for fan speed control | Sentera Controls | ATR-1100L25

    ATR-1100L25 – Sentera Controls single-phase 230 VAC autotransformer up to 10 A with 8 secondary voltage taps (0-80-100-120-150-170-190-230 VAC) and screw terminals. Designed for installation in a control panel or equipment when an output voltage lower than the mains voltage is needed – primarily for speed control of single-phase AC fans.

    Key idea:
    This is the “heart” without an enclosure: an autotransformer from which a panel builder or automation installer creates their own stepped fan speed controller with their own switch, relays or controller. ATR-1100L25 is intended for high-power fans or fan groups in industrial and commercial premises (up to 10 A).
    What it is for ATR-1100L25:
    This model is designed for high-power fans (up to 10 A) – industrial fans in production halls, warehouses, farm buildings or a larger group of fans.
    Max. current
    10 A
    Output taps
    80 / 100 / 120 / 150 / 170 / 190 / 230 VAC
    Primary voltage
    230 VAC ±10 %, 50–60 Hz
    Protection
    IP20, for control panel installation

    Operating principle

    The autotransformer has a single winding with several taps: the 230 VAC primary voltage is applied to L, N, and the secondary voltages are taken from the taps – 80, 100, 120, 150, 170, 190 or 230 VAC. Screw terminals; the mounting brackets allow quick fixing to the control panel mounting plate.

    Fan speed is changed in steps: the motor is connected to the desired tap via a switch, relays or controller outputs (not included). Control is stepped, not stepless.

    The output voltage is sinusoidal because it is obtained by a transformer rather than by electronically “chopping” the sine wave. Therefore the motor runs quietly and does not hum – the autotransformer is also suitable for AC motors that hum at low speed with an electronic controller. The manufacturer specifies quiet operation and anti-corrosion protection.

    Engineer's note: the speed of an AC asynchronous motor is reduced by increasing slip, so less energy is saved than with an EC fan or frequency inverter. The greatest advantage of transformer control is quiet and reliable motor operation at all steps.

    Benefits ATR-1100L25?
    For panel builders and automation – a flexible basis for stepped control: 7 operating voltages from 80 to 230 VAC, class F insulation and compact dimensions.

    Technical specifications

    Product type Single-phase autotransformer for fan speed control
    Manufacturer / code Sentera Controls / ATR-1100L25
    Series ATR-1 (1.5 / 2.5 / 3.5 / 5 / 7.5 / 10 / 13 / 16 / 20 A)
    Primary voltage 230 VAC ±10 %, 50–60 Hz
    Max. current 10 A
    Secondary voltage taps 0-80-100-120-150-170-190-230 VAC
    Terminals Screw-type; L, N, PE and output taps
    Construction class II
    Insulation class F (155 °C)
    Electrical strength 2 500 VAC
    Protection class IP20 (EN 60529), for indoor use only
    Operating environment Up to +35 °C, < 90 % rH non-condensing
    Dimensions A / B / C / D / E 135 / 128 / 135 / 112.5 / 92 mm (according to the datasheet drawing)
    Weight 7.50 kg
    Compliance LVD 2014/35/EU, EMC 2014/30/EU, RoHS 2011/65/EU, WEEE 2012/19/EU

    Manufacturer documentation

    ✔ Recommended by Elektrotechnikos sprendimai

    Original manufacturer documentation – technical data, wiring diagrams and installation instructions.

    Main functions

    • 8 output taps – 0, 80, 100, 120, 150, 170, 190 and 230 VAC – freely selectable speed steps.
    • Sinusoidal output voltage – quiet motor operation without the hum of electronic control.
    • Screw terminals – fast and reliable connection.
    • Mounting brackets – simple installation on the control panel mounting plate.
    • Class F insulation – the insulation withstands up to 155 °C.

    Where is it used?

    • Ventilation and automation control panels
    • Ventilation unit manufacturing (OEM)
    • Step speed control of single-phase AC fans
    • Equipment requiring a voltage lower than mains voltage
    • Livestock and greenhouse ventilation systems

    On-demand operation

    For the panel builder.
    Compact autotransformer with screw terminals and brackets.
    For the automation engineer.
    7 operating voltages – the steps can be controlled by the controller relays.
    For the electrician.
    Clear taps and simple connection.

    Application guide: how it is used in practice

    Typical ATR-1100L25 applications:

    Site What is connected Result Installer's note
    Ventilation control panel Step switch → selected taps, motor → switch output Manual step speed control Select 3–5 taps according to the required speeds
    Control by a controller (PLC) Relay / contactor outputs → taps Automatic speed switching according to a program Ensure that only one tap is switched on at a time
    Ventilation unit manufacturing Motor → one tap (e.g. 170 VAC) Fixed, reduced fan speed Select the tap during testing
    A motor that hums with an electronic controller Autotransformer instead of an electronic controller Quiet motor operation Control becomes step-based

    How to select the controller current

    Rated current of the motor(s) Recommended model
    up to 1.5 A ATR-1-15L25 (1.5 A)
    1.5–2.5 A ATR-1-25L25 (2.5 A)
    2.5–3.5 A ATR-1-35L25 (3.5 A)
    3.5–5 A ATR-1-50L25 (5 A)
    5–7.5 A ATR-1-75L25 (7.5 A)
    7.5–10 A ATR-1100L25 (10 A) ← this model
    10–13 A ATR-1130L25 (13 A)
    13–16 A ATR-1160L25 (16 A)
    16–20 A ATR-1200L25 (20 A)
    Rule: autotransformer max. current ≥ motor rated current (see the motor nameplate). When connecting several fans – motors of the same type – add up their rated currents.
    When to choose another solution: a ready-made controller with an enclosure (IP54) and knob needed – STR-1; with an external switch – RTR-1; with 0-10 VDC control – STVS1; with Modbus RTU – RTVS8; with TK and automatic restart – STRA1; stepless electronic control – EVS-1.

    Pros

    • Sinusoidal output voltage – quiet motor operation
    • 8 taps: 0-80-100-120-150-170-190-230 VAC
    • Screw terminals and mounting brackets
    • Class F insulation, 2 500 VAC
    • Compact – 7.50 kg
    • Wide series range: 1.5–20 A

    Cons / limitations

    • IP20 – must be installed in a control panel or equipment enclosure
    • Has no switch, fuse or indication – these are selected by the control panel designer
    • Step control, not stepless
    • Single-phase AC motors only; not suitable for EC fans
    • Operating temperature up to +35 °C, indoor use only

    Safety and installation notes

    • Installation and connection must be carried out by a qualified electrician with the power disconnected.
    • Always connect the protective earth (PE).
    • IP20 – install only in a closed control panel or equipment enclosure protected against contact.
    • The load current must not exceed 10 A; provide overload and short-circuit protection according to the design.
    • Connect the motor to only one tap at a time – connecting several taps causes a short circuit between winding sections.
    • For indoor use only (up to +35 °C, < 90 % rH).

    Quick selection guide

    10 A
    230 VAC
    8 taps
    Sinusoidal voltage
    IP20
    Suitable when you need:
    • stepped single-phase AC fan control in a control panel up to 10 A;
    • control panel and ventilation unit manufacturing;
    • quiet motor operation with sinusoidal voltage.
    Check before use:
    • the motor rated current;
    • how the taps will be switched (switch, relays, controller);
    • the space in the control panel – dimensions, weight and ventilation (up to +35 °C).
    Important reminder: ATR-1100L25 – autotransformer without enclosure (IP20), switch or fuse; for a ready-made solution choose STR-1.

    FAQ

    How does it differ from STR-1?
    ATR-1 – autotransformer only (IP20) for installation in a control panel; STR-1 – ready-made controller with IP54 enclosure, knob and fuse.
    What voltages can be obtained?
    80, 100, 120, 150, 170, 190 and 230 VAC (taps 0-80-100-120-150-170-190-230 VAC).
    How do I switch the speeds?
    With a switch, relays or controller that connect the motor to the desired tap; they are not included.
    Is it suitable for EC fans?
    No, EC fans are controlled with a 0-10 VDC / PWM signal, e.g. with an SDP potentiometer.
    Can several fans be connected?
    Yes, provided their total rated current does not exceed 10 A.

    Single-phase autotransformer for fan speed control | Sentera Controls | ATR-1100L25

    Sentera ATR-1100L25 – single-phase 230 VAC autotransformer up to 10 A for fan speed control, 8 taps 0-80-100-120-150-170-190-230 VAC, screw terminals, class F insulation, IP20.

    Illustrative image may have been created using AI. The appearance of the product may differ slightly from the image shown. Please refer to the technical specification.

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