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  • New item   -263.66€Transformer three-phase fan motor speed controller with airflow-dependent gas valve interlock | TK | 4A | 400VAC | surface-mounted | IP54 | Sentera Controls | SFPR4-40L40
    New item   -263.66€Transformer three-phase fan motor speed controller with airflow-dependent gas valve interlock | TK | 4A | 400VAC | surface-mounted | IP54 | Sentera Controls | SFPR4-40L40 1
    New item   -263.66€Transformer three-phase fan motor speed controller with airflow-dependent gas valve interlock | TK | 4A | 400VAC | surface-mounted | IP54 | Sentera Controls | SFPR4-40L40 2
    New item   -263.66€Transformer three-phase fan motor speed controller with airflow-dependent gas valve interlock | TK | 4A | 400VAC | surface-mounted | IP54 | Sentera Controls | SFPR4-40L40 3
    New item   -263.66€Transformer three-phase fan motor speed controller with airflow-dependent gas valve interlock | TK | 4A | 400VAC | surface-mounted | IP54 | Sentera Controls | SFPR4-40L40 4

    Transformer three-phase fan motor speed controller with airflow-dependent gas valve interlock | TK | 4A | 400VAC | surface-mounted | IP54 | Sentera Controls | SFPR4-40L40

    Code: SFPR4-40L40
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  • Product description

    Transformer three-phase fan motor speed controller with airflow-dependent gas valve interlock | TK | 4A | 400VAC | surface-mounted | IP54 | Sentera Controls | SFPR4-40L40

    SFPR4-40L40 – Sentera Controls transformer speed controller for three-phase 400 VAC fan motors up to 4 A with air flow monitoring: the flow or pressure switch input controls the relay for a gas valve. 5 steps, sinusoidal voltage, TK terminals.

    Key idea:
    A controller for gas heaters and processes where combustion is permitted only when there is air flow: if no flow is detected within 60 s, the relay cuts off the gas supply.
    What it is for SFPR4-40L40:
    This model is designed for more powerful fans (up to 4 A) – roof or duct fans in warehouses, workshops, halls or a group of fans.
    Max. motor current
    4 A
    Airflow monitoring
    FL input + relay 230 VAC / 6 A
    Motor protection
    TK terminals
    Supply / protection
    3×400 VAC ±10 % + N; IP54

    Operating principle

    The controller is wall-mounted. The 3×400 VAC supply is connected to R, S, T and N, the motor – to U, V, W, the thermal contacts – to TK, a flow or pressure switch – to FL (normally closed), remote start / thermostat – to NC, and a gas valve or actuator – via the relay contacts COM / NO / NC.

    The controller is based on an autotransformer with several taps (steps). When the knob is turned, the motor is switched to another tap, so the output voltage changes in steps rather than steplessly. Regulated output voltages: 0 – 130 – 180 – 230 – 300 – 400 VAC (±5 %).

    The output voltage is SINUSOIDAL – without phase cutting as in electronic controllers. Therefore the motor runs quietly even at low speed, does not heat up due to higher harmonics and does not interfere with other equipment. This is the solution for motors that hum or buzz when controlled by an electronic controller.

    Air flow monitoring: the relay is controlled according to the state of the flow or pressure switch. If no air flow is detected within 60 seconds, the gas flow is stopped. The gas valve can be supplied with 230 VAC from L1 / N (with an external fuse of up to 6 A in phase R) or from an external 24 VDC source.

    Benefits SFPR4-40L40?
    Fan speed control and an airflow interlock for the gas valve in one device – no separate airflow monitoring relay needed.

    Technical specifications

    Product type Transformer three-phase fan controller with airflow monitoring
    Manufacturer / code Sentera Controls / SFPR4-40L40
    Series SFPR4 (1.5 / 2.5 / 4 / 6 / 8 A)
    Supply voltage 3×400 VAC ±10 %, 50–60 Hz, with neutral (R, S, T, N)
    Max. motor current 4 A
    Regulated output (U, V, W) 0 – 130 – 180 – 230 – 300 – 400 VAC (±5 %), positions 0–5, sinusoidal voltage
    Unregulated output (L1, N) 230 VAC, 2 A (in all positions 1–5)
    Flow / pressure switch input (FL) Normally closed contact
    Relay output (COM, NO, NC) 230 VAC, 6 A – for a gas valve or actuator
    Lockout logic If no air flow is detected within 60 s, the gas flow is stopped
    Gas valve supply 230 VAC from L1 / N with an external max. 6 A fuse in phase R, or external 24 VDC
    Remote start / thermostat NC input (normally closed)
    Motor protection TK terminals for motor thermal contacts
    Control 5-position rotary switch with OFF position
    Indication Blue LED – device switched on
    Cable glands 8–13 mm
    Housing Metal, powder-coated RAL 7035
    Protection class IP54 (EN 60529), for indoor use only
    Operating environment -20…+35 °C, 5–95 % rH non-condensing
    Dimensions A 425 / B 300 / C 175 / D 255 / E 355 mm (letter meanings – according to the datasheet drawing)
    Packaging (L × W × H) 440×310×200 mm
    Weight 18.2 kg (net)
    Compliance LVD 2006/95/EC (EN 61558-1, EN 61558-2-13), WEEE 2012/19/EU, RoHS 2011/65/EU

    Manufacturer documentation

    ✔ Recommended by Elektrotechnikos sprendimai

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

    Main functions

    • Air flow monitoring – a flow or pressure switch (FL) confirms that the fan is actually delivering air.
    • Relay 230 VAC / 6 A – gas valve or actuator control based on airflow status.
    • 60 s lockout – if no airflow is detected within 60 s, the gas supply is cut off.
    • TK terminals – connection of motor thermal contacts.
    • NC input – remote start or thermostat.
    • Sinusoidal output voltage – quiet motor operation at all 5 steps.

    Where is it used?

    • Gas air heaters and heating systems with a fan
    • Production processes where combustion is permitted only when there is air flow
    • Greenhouses, livestock and poultry buildings with gas heating
    • Industrial ventilation systems with three-phase fans

    On-demand operation

    For the heating / ventilation installer.
    Airflow interlock and fan control in one device – a simpler wiring diagram.
    For the electrician.
    Clear FL, NC, TK, COM / NO / NC terminals – quick connection.
    For the building owner.
    Gas is supplied only when the fan is actually blowing air.

    Application guide: how it is used in practice

    Typical SFPR4-40L40 applications:

    Site What is connected Result Installer's note
    Gas air heater Flow / pressure switch → FL; gas valve → COM / NO The valve opens only when airflow is present If there is no flow within 60 s, the gas is stopped
    Temperature-based heating Thermostat → NC input The system is switched on and off according to temperature Use a voltage-free contact
    Valve 230 VAC Valve supply from L1 / N No separate power source is needed External fuse of up to 6 A in phase R
    Valve 24 VDC External 24 VDC source via relay contacts Low-voltage valve control Relay contact limits – 230 VAC / 6 A
    Fan with thermal contacts Motor TK → TK terminals The motor is protected against overheating Connect the TK circuit according to the diagram in the manual

    How to select the controller current

    Rated current of the motor(s) Recommended model
    up to 1.5 A SFPR4-15L40 (1.5 A)
    1.5–2.5 A SFPR4-25L40 (2.5 A)
    2.5–4 A SFPR4-40L40 (4 A) ← this model
    4–6 A SFPR4-60L40 (6 A)
    6–8 A SFPR4-80L40 (8 A)
    Rule: controller max. current ≥ motor rated current (see the motor nameplate). When connecting several fans – motors of the same type – add up their rated currents. Choose a margin if the motor current is close to the model's limit or the fan often runs at the maximum step.
    When to choose another solution: without airflow monitoring – STR-4 or STRS4 (with TK); with NO/NC and alarm – STRA4 or STTA4; for 0-10 VDC control – STVS4; for two speeds – SC2A4 or ST2R4.

    Pros

    • Air flow monitoring and gas valve interlock
    • Relay 230 VAC / 6 A
    • TK terminals
    • NC remote start input
    • Sinusoidal output voltage
    • Metal IP54 enclosure

    Cons / limitations

    • Series only up to 8 A
    • Flow / pressure switch is not included
    • Speed is changed only with the knob
    • Step (not stepless) control – the speed is selected from fixed voltages
    • Heavy weight and large dimensions compared with electronic controllers
    • Indoor use only, operating temperature up to +35 °C
    • Not suitable for EC fans and motors controlled by a frequency inverter

    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).
    • Check that the motor is suitable for voltage control and that its rated current does not exceed 4 A.
    • The supply requires a neutral (N).
    • When supplying the gas valve from L1 / N, an external fuse of up to 6 A is required in phase R.
    • Gas equipment interlocks must comply with the requirements of the gas appliance manufacturer and applicable regulations.
    • The device is heavy – fix it to a load-bearing wall or structure using suitable fixings.
    • For indoor use only (-20…+35 °C, non-condensing); leave space for cooling.

    Quick selection guide

    4 A
    3×400 VAC
    Airflow monitoring
    Relay 6 A
    TK
    IP54
    Suitable when you need:
    • a three-phase fan up to 4 A with a gas heater interlock;
    • systems where combustion is only permitted when airflow is present;
    • motors with thermal contacts.
    Check before use:
    • the motor rated current and whether it is voltage-controllable;
    • the flow or pressure switch type (FL – normally closed);
    • the gas valve supply voltage (230 VAC or 24 VDC).
    Important reminder: SFPR4-40L40 is a fan controller with a flow interlock, not a gas burner controller.

    FAQ

    How does the air flow monitoring work?
    A flow or pressure switch is connected to FL; if no airflow is detected within 60 s, the relay cuts off the gas supply.
    What valve can be controlled?
    230 VAC (from L1 / N with an external fuse of up to 6 A) or 24 VDC from an external source; relay contacts – 230 VAC / 6 A.
    Is the flow switch included?
    The datasheet lists it as a connectable external device.
    What voltages does the motor receive?
    0, 130, 180, 230, 300 and 400 VAC (±5 %).
    Are there models for higher currents?
    SFPR4 series – up to 8 A.

    Transformer three-phase fan motor speed controller with airflow-dependent gas valve interlock | TK | 4A | 400VAC | surface-mounted | IP54 | Sentera Controls | SFPR4-40L40

    Sentera SFPR4-40L40 – transformer speed controller for three-phase fans up to 4 A with airflow monitoring and a gas valve relay (230 VAC / 6 A), 3×400 VAC, TK, 5 steps, sinusoidal voltage, IP54.

    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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