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  • New item   -234.36€Transformer fan motor speed controller | Modbus RTU | 3.5A | 115-230VAC | surface-mounted | IP54 | Sentera Controls | RTVS8-35L22
    New item   -234.36€Transformer fan motor speed controller | Modbus RTU | 3.5A | 115-230VAC | surface-mounted | IP54 | Sentera Controls | RTVS8-35L22 1
    New item   -234.36€Transformer fan motor speed controller | Modbus RTU | 3.5A | 115-230VAC | surface-mounted | IP54 | Sentera Controls | RTVS8-35L22 2
    New item   -234.36€Transformer fan motor speed controller | Modbus RTU | 3.5A | 115-230VAC | surface-mounted | IP54 | Sentera Controls | RTVS8-35L22 3
    New item   -234.36€Transformer fan motor speed controller | Modbus RTU | 3.5A | 115-230VAC | surface-mounted | IP54 | Sentera Controls | RTVS8-35L22 4

    Transformer fan motor speed controller | Modbus RTU | 3.5A | 115-230VAC | surface-mounted | IP54 | Sentera Controls | RTVS8-35L22

    Code: RTVS8-35L22
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  • Product description

    Transformer fan motor speed controller | Modbus RTU | 3.5A | 115-230VAC | surface-mounted | IP54 | Sentera Controls | RTVS8-35L22

    RTVS8-35L22 – Sentera Controls transformer fan speed controller with Modbus RTU for single-phase AC motors up to 3.5 A. Supplied from a 115 or 230 VAC network, it changes the speed in 5 sinusoidal voltage steps (0-(80)-110-140-170-190-230 VAC at 230 VAC) – automatically according to the connected Sentera sensor or manually via Modbus.

    Key idea:
    Quiet transformer control integrated into digital automation: with a Sentera IAQ sensor connected, ventilation runs according to temperature, humidity, CO₂, TVOC, CO or NO₂, and the BMS monitors and controls the controller via Modbus RTU. RTVS8-35L22 is intended for medium-sized duct, roof or axial fans (up to 3.5 A).
    What it is for RTVS8-35L22:
    This model is intended for more powerful fans (up to 3.5 A) – roof or duct fans in warehouses, workshops, halls or a group of fans.
    Max. motor current
    3.5 A
    Control
    Modbus RTU (RS485), auto / manual
    Power supply
    115 or 230 VAC, 50–60 Hz
    Protection
    IP54, TK terminals

    Operating principle

    The supply (L, N, PE), the motor to the regulated output and the motor thermal protection contacts to the TK terminals are connected. The controller has a relay (unregulated) output of 16 A for resistive load and two RJ45 sockets: the main one – for Sentera devices (24 VDC supply and Modbus), and the “gateway” – for a computer with the 3SModbus software, a Sentera internet module or a BMS.

    Inside is an autotransformer with several output taps. Each step supplies the motor with a different preset voltage: 0-(80)-110-140-170-190-230 VAC (at 115 VAC: 0-(40)-55-70-85-95-115 VAC). Control is stepped, not stepless – speed changes in fixed increments. The lowest (80 V / 40 V) tap is present but not connected; other voltages for the 5 steps can be selected by changing the internal wiring.

    In automatic mode the speed is selected based on data from the Sentera device (IAQ sensor or Modbus RTU potentiometer) connected to the main RJ45 socket; via Modbus you select the control variable (temperature, humidity, CO₂, TVOC, CO, NO₂), the step sequence (from low to high or vice versa), hysteresis of 2–10 % and a switching interval from 5 s to 10 min. In manual mode the speed is set via a Modbus register. Analogue control via DADCM is also possible.

    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, heats up less and does not hum – the transformer speed controller is also suitable for AC motors that audibly hum at low speed with an electronic (triac) controller. 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 RTVS8-35L22?
    The quietness of a transformer controller and the flexibility of Modbus RTU in one device: air-quality-based control without a separate controller, settings and diagnostics via BMS or computer.

    Technical specifications

    Product type Transformer fan speed controller with Modbus RTU
    Manufacturer / code Sentera Controls / RTVS8-35L22
    Series RTVS8 (1.5 / 2.5 / 3.5 / 5 / 7.5 A)
    Supply voltage 115 or 230 VAC, 50–60 Hz
    Max. motor current 3.5 A
    Regulated output 0-(80)-110-140-170-190-230 VAC (230 VAC) / 0-(40)-55-70-85-95-115 VAC (115 VAC), sinusoidal voltage
    Relay (unregulated) output 16 A for resistive load; controlled manually or automatically via Modbus
    Communication Modbus RTU (RS485); RJ45 main socket (24 VDC, A, /B, GND) and RJ45 “gateway” socket (A, /B)
    Modes Automatic (according to the connected Sentera device) and manual (via Modbus)
    Control variables Temperature, humidity, CO₂, TVOC, CO, NO₂
    Hysteresis / switching interval 2–10 % / 5 s – 10 min
    Analogue control Via DADCM
    Motor thermal protection TK terminals
    Indication Communication, alarm, relay and output LEDs
    Fuse T-5.0 A-H, 5×20 mm
    Housing Plastic R-ABS, UL94-V0, grey RAL 7035
    Protection class IP54 (EN 60529), for indoor use only
    Operating environment -10…+35 °C, 5–85 % rH non-condensing
    Weight 5.0 kg net / 5.4 kg gross
    Packaging dimensions 325×210×155 mm
    Compliance LVD 2014/35/EU (EN 60529, EN 60730-1), EMC 2014/30/EU (EN 60730-1, EN 61000-6-1, EN 61000-6-3), 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

    • Modbus RTU (RS485) – integration into the BMS, settings via the 3SModbus software or a Sentera internet module.
    • Automatic mode – the speed is selected according to the temperature, humidity, CO₂, TVOC, CO or NO₂ measured by a Sentera IAQ sensor.
    • Hysteresis and switching interval – 2–10 % and 5 s – 10 min – stable operation without frequent step switching.
    • Relay output 16 A – for a damper, heater or other device, controlled manually or automatically via Modbus.
    • TK terminals and alarm LED – motor overheating and other faults are visible immediately.
    • 115 / 230 VAC – also suitable for 115 V networks (export projects).
    • SenteraWeb – via the Sentera internet module, the controller can be connected to the SenteraWeb cloud – remote control, monitoring and alerts via the internet.

    Where is it used?

    • Air-quality-based ventilation (CO₂, TVOC) in offices, schools and halls
    • Buildings with a BMS / Modbus RTU network
    • Production and storage premises
    • Livestock buildings (control according to temperature, humidity or NO₂)
    • Sites with 115 V mains

    On-demand operation

    For the automation engineer.
    Modbus RTU, clear registers and two RJ45 connectors – fast integration.
    For the electrician.
    TK, relay output and LED diagnostics without additional modules.
    For the ventilation installer.
    With a Sentera IAQ sensor the system works without a separate controller, and the motor runs quietly.

    Application guide: how it is used in practice

    Typical RTVS8-35L22 applications:

    Site What is connected Result Installer's note
    Classroom, office or hall Sentera IAQ (CO₂) sensor → main RJ45 Speed increases as the CO₂ concentration rises Set the control variable and hysteresis via Modbus
    Building with BMS BMS → RJ45 “gateway” (Modbus RTU) BMS sets the speed and sees the status Manual mode – speed via a Modbus register
    Commissioning and adjustment Computer → CNVT-USB-RS485-V2 → “gateway” Parameters are set with the 3SModbus software Modbus settings can be reset via the PROG contacts
    Livestock building Temperature / humidity sensor → main RJ45; motor TK → TK Ventilation based on indoor climate, motor protected Select the switching interval so that the steps do not jump back and forth
    Damper or heater Device → relay output Switched on manually or automatically via Modbus Relay load – up to 16 A (resistive)

    How to select the controller current

    Rated current of the motor(s) Recommended model
    up to 1.5 A RTVS8-15L22 (1.5 A)
    1.5–2.5 A RTVS8-25L22 (2.5 A)
    2.5–3.5 A RTVS8-35L22 (3.5 A) ← this model
    3.5–5 A RTVS8-50L22 (5 A)
    5–7.5 A RTVS8-75L22 (7.5 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.
    When to choose another solution: manual control is sufficient – STR-1; control by a 0-10 VDC signal without Modbus – STVS1; automatic restart and alarm output without Modbus – STRA1; stepless electronic control with Modbus – EVS-1; for an EC fan – SDP potentiometers; for a three-phase motor – STR-4.

    Pros

    • Sinusoidal output voltage – quiet motor operation
    • Modbus RTU (RS485), two RJ45 connectors
    • Automatic mode with Sentera IAQ sensors
    • Supply 115 or 230 VAC
    • TK terminals and LED diagnostics
    • Relay output 16 A

    Cons / limitations

    • Step control (5 steps), not stepless
    • Higher weight than electronic controllers (5.0 kg net)
    • A Modbus tool is required for settings (3SModbus, BMS or Sentera module)
    • Operating temperature -10…+35 °C, humidity up to 85 % rH
    • Single-phase AC motors only; not suitable for EC fans

    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).
    • The rated current of the motor (or the total of several motors) must not exceed 3.5 A; replace the fuse only with one of the same type and rating.
    • The controller is intended only for single-phase, voltage-controllable AC motors; it is not suitable for EC fans or three-phase motors.
    • Route data (RJ45 / RS485) cables separately from power cables.
    • Do not exceed 16 A on the relay output (resistive load).
    • For indoor use only (-10…+35 °C, 5–85 % rH).

    Quick selection guide

    3.5 A
    115/230 VAC
    Modbus RTU
    TK
    Sinusoidal voltage
    IP54
    Suitable when you need:
    • quiet stepped AC fan control up to 3.5 A via Modbus RTU;
    • air-quality-based ventilation with Sentera IAQ sensors;
    • integration into the BMS.
    Check before use:
    • the motor rated current and the mains voltage (115 or 230 VAC);
    • which Sentera sensor or BMS you will connect and how you will configure Modbus;
    • the ambient conditions (-10…+35 °C, up to 85 % rH).
    Important reminder: RTVS8-35L22 does not control EC fans or three-phase motors.

    FAQ

    Is a separate controller required?
    No, if you use a Sentera IAQ sensor: it is connected directly to the main RJ45 socket, and the controller selects the step itself.
    Can it be controlled by a 0-10 V signal?
    The datasheet specifies analogue control via DADCM; for direct 0-10 VDC control without Modbus, the STVS1 series is suitable.
    How do I set the parameters?
    Via Modbus RTU: 3SModbus software on a computer (e.g. via a CNVT-USB-RS485-V2 adapter), a Sentera internet module or a BMS.
    Is it suitable for a 115 V network?
    Yes, 115 or 230 VAC supply; at 115 VAC the steps are 55-70-85-95-115 VAC.
    Can several fans be connected?
    Yes, provided their total rated current does not exceed 3.5 A.

    Transformer fan motor speed controller | Modbus RTU | 3.5A | 115-230VAC | surface-mounted | IP54 | Sentera Controls | RTVS8-35L22

    Sentera RTVS8-35L22 – transformer fan speed controller with Modbus RTU up to 3.5 A, 115/230 VAC, 5 sinusoidal voltage steps, automatic mode with IAQ sensors, TK protection, relay output, 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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