VENTS single-phase switchboard with speed controller. RSA5E-4-M

VENTS RSA5E-4-M is designed to regulate the air flow rate of compatible single-phase fans by changing the motor speed. Unlike conventional electronic regulators, the model uses a transformer control principle , offering five predefined operating levels.

The desired speed is set via a mechanical rotary switch on the front panel . This makes control easy and allows the air flow to be adapted to the specific needs of the ventilation system – for example, a lower speed under normal conditions and a higher speed when intensive air exchange is required.

One of the important advantages of the RSA5E-4-M is the integrated motor protection . The controller can work with the thermal contacts of a compatible fan. If the thermal relay in the motor is activated due to overheating, the power supply to the fan is interrupted. After normalization of conditions, the power supply is restored automatically.

Additional terminals are also provided for connecting an external thermostat or air damper motor , which allows the regulator to be integrated into more complex air conditioning and ventilation installations.

The housing of the RSA5E-4-M model is metal and is designed for surface wall mounting. The protection is IP21 , and the permissible ambient temperature during operation is from +5°C to +40°C .

Technical characteristics

✔️ Manufacturer: VENTS
✔️ Model: RSA5E-4-M
✔️ Type: Transformer speed controller
✔️ Control: Stepper
✔️ Number of speeds: 5
✔️ Phases: 1
✔️ Supply voltage: 230 V / 50 Hz
✔️ Nominal motor voltage: 230 V / 50 Hz
✔️ Maximum rated load: 4.0 A
✔️ Fuse: 5.0 A
✔️ Protection level: IP21
✔️ Operating temperature: +5°C to +40°C
✔️ Housing: Metal
✔️ Installation: Surface wall mount
✔️ Dimensions: 241 × 184 × 132 mm
✔️ Weight: 4.5 kg
✔️ Terminals: screw type, 0.5–2.5 mm² .

🛡️ Features and protections

The RSA5E-4-M offers more than just speed control:

✔️ 5-speed fan speed adjustment
✔️ Mechanical rotary switch
✔️ Integrated motor overheating protection
✔️ Automatic power recovery after temperature normalization
✔️ Possibility to connect a thermostat
✔️ Possibility to control an air damper actuator .

🔧 Application

VENTS RSA5E-4-M is suitable for controlling compatible single-phase fans in:

• Greenhouses
• Nurseries
• Warehouses
• Production premises
• Workshops
• Technical premises
• Supply ventilation systems
• Suction ventilation systems
• Other professional systems where step control of the air flow is required.

🔌 Working principle

When selecting a different position of the rotary switch, the regulator supplies a different voltage to the fan motor. In this way, the speed and, accordingly, the air flow rate are changed in five separate stages .

This type of control is particularly suitable for compatible AC motors when reliable regulation is sought without the need for complex electronics.

📋 Installation and use

1. Mount the controller vertically on a stable wall.
2. Connect the power supply and fan to the corresponding terminals according to the VENTS wiring diagram.
3. If the motor has suitable thermal contacts, connect them to the controller's protection circuit.
4. If necessary, connect an external thermostat or air damper actuator.
5. After checking the electrical installation, turn on the power.
6. Select the required speed using the rotary switch.

⚠️ Important: The maximum rated load of the RSA5E-4-M is 4.0 A. Before connecting, the rated current of the fan motor and its compatibility with transformer regulation must be checked. The electrical connection must be made according to the diagram and the manufacturer's requirements.

💡 Tip from Urban Botaniks: A transformer regulator is a good choice for ventilation systems where the fan does not need to run at maximum speed all the time. Selecting an appropriate lower setting can reduce air flow and noise, while keeping the maximum speed available for periods when more intensive air exchange is needed.