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EU declaration conformity
Fan speed controller 400 V | TK monitoring | remote run-stop | 4 A
Product description
This is a 5-step fan speed controller for three-phase 400 VAC motors with thermal contacts. The motor current of 4 A. Fan speed is set manually via a rotary switch with an OFF position. The motor can be enabled or disabled remotely using the extra inputs.
To ensure motor safety, STRA4 incorporates a TK monitoring function. In case of motor overheating, the TK monitoring functionality deactivates the motor in order to prevent damage.
If a power failure occurs, the motor restarts automatically without any manual intervention.
STRA4 includes an alarm output and an unregulated output. The alarm output triggers external devices to generate alarms. The unregulated output can control external devices to confirm normal operation or activate additional equipment.
Fan speed is regulated by reducing the motor voltage using autotransformer technology. This ensures that the output voltage has a perfect sine shape, guaranteeing silent motor operation and minimizing electrical noise.
The enclosure is designed for surface mounting and features IP54 protection against ingress of dirt, dust, and moisture.
Additional specifications and description
Five-step fan control with advanced features
This fan speed controller features a rotary switch with five positions, each corresponding to a different fan speed. The technology employed in this controller utilizes autotransformers to reduce fan speed and motor voltage in five incremental steps. The available output voltages in the series are 130, 180, 230, 300, and 400 VAC. Additionally, it is equipped with TK contacts for thermal motor protection and run/stop contacts (NC – closed / NO open) for external or remote starting and stopping.
Reliable autotransformer technology
The autotransformer technology employed in this controller is renowned for its reliability and robustness. It generates motor voltage with a perfect sinusoidal shape, ensuring exceptionally quiet motor operation and an extended service life. Any residual electrical noise generated by the autotransformers is effectively filtered by a special impregnation.
Compatibility and motor wiring
This fan speed controller is appropriate only for 3-phase, voltage-controllable motors. If you are uncertain whether your motor supports voltage control, it is advisable to contact the motor manufacturer.
When wiring a three-phase fan motor, specific guidelines must be followed to ensure correct connections and safe operation. The controller is typically supplied using the R, S, and T terminals, while the motor leads are labeled U, V, and W for the three phases. The motor voltage should match the available power supply voltage, and the motor may need to be wired in a delta (Δ) or star (Y) configuration, as indicated by the motor nameplate or manufacturer's documentation. Always comply with grounding guidelines specified by local electrical codes.
Remote control possibilities
The STRA4 series introduces additional control options through extra inputs. These inputs allow remote enabling or disabling of the motor. For instance, you can connect a smoke alarm to the input. In the event of a smoke alarm, the motor is disabled, overriding the status of other inputs. This feature is especially useful in environments where the spread of toxic smoke gases through the ventilation system needs to be slowed down. Additionally, you can connect a door contact to control an air curtain. When the door opens, the contact triggers the air curtain via the STRA4 controller's input. The air curtain will run at a fixed speed.
Thermal monitoring with TK contacts
This fan speed controller offers the same speed control as the standard STR-4 series but with more options. One of them is monitoring thermal motor contacts or TK contacts. These contacts monitor the temperature inside the motor windings. Thanks to TK contacts, the motor is disabled if it overheats, preventing motor damage and activating the alarm output. This alarm output can be used to connect an external alarm module, such as a buzzer or a light. If your motor lacks TK contacts, you must bridge the two TK terminals of the controller to simulate normal motor temperature.
Automatic reset after power failure
The STRA4 series includes an automatic reset feature in the event of a power failure. When the power is restored after an outage, the connected motor will restart automatically. This is a convenient and time-saving feature, especially in applications where continuous motor operation is essential without human intervention in the event of a power interruption. This feature is particularly valuable in ventilation systems, ensuring a constant fan speed for proper air circulation and control.
Outputs for external devices
The unregulated output provides a fixed output voltage of 230 VAC when the motor is enabled. This output is always either ON (230 Volt) or OFF (0 Volt) and cannot be adjusted or regulated. It has a maximum current rating of 2 A. This unregulated output allows for the simultaneous operation of other devices or equipment that need to work in coordination with the fan. For example, you can connect an indicator lamp to this output to provide a visual indication when the fan is running. If you have air ducts with closing valves that need to be opened or closed when the fan is running, you can use this output to control their actuation.
Durable and cooling-optimized enclosure for indoor use
The enclosure of this controller is constructed from high-quality steel, offering robustness and excellent protection against impacts. It is rated with an IP54 protection level, effectively guarding against dust and water ingress. This fan speed controller is designed for indoor installation on walls or panels. To ensure optimal cooling and performance:
• Select a cool installation location.
• Avoid direct sunlight and high-temperature areas.
• Use the controller exclusively for indoor applications.
This fan speed controller features a rotary switch with five positions, each corresponding to a different fan speed. The technology employed in this controller utilizes autotransformers to reduce fan speed and motor voltage in five incremental steps. The available output voltages in the series are 130, 180, 230, 300, and 400 VAC. Additionally, it is equipped with TK contacts for thermal motor protection and run/stop contacts (NC – closed / NO open) for external or remote starting and stopping.
Reliable autotransformer technology
The autotransformer technology employed in this controller is renowned for its reliability and robustness. It generates motor voltage with a perfect sinusoidal shape, ensuring exceptionally quiet motor operation and an extended service life. Any residual electrical noise generated by the autotransformers is effectively filtered by a special impregnation.
Compatibility and motor wiring
This fan speed controller is appropriate only for 3-phase, voltage-controllable motors. If you are uncertain whether your motor supports voltage control, it is advisable to contact the motor manufacturer.
When wiring a three-phase fan motor, specific guidelines must be followed to ensure correct connections and safe operation. The controller is typically supplied using the R, S, and T terminals, while the motor leads are labeled U, V, and W for the three phases. The motor voltage should match the available power supply voltage, and the motor may need to be wired in a delta (Δ) or star (Y) configuration, as indicated by the motor nameplate or manufacturer's documentation. Always comply with grounding guidelines specified by local electrical codes.
Remote control possibilities
The STRA4 series introduces additional control options through extra inputs. These inputs allow remote enabling or disabling of the motor. For instance, you can connect a smoke alarm to the input. In the event of a smoke alarm, the motor is disabled, overriding the status of other inputs. This feature is especially useful in environments where the spread of toxic smoke gases through the ventilation system needs to be slowed down. Additionally, you can connect a door contact to control an air curtain. When the door opens, the contact triggers the air curtain via the STRA4 controller's input. The air curtain will run at a fixed speed.
Thermal monitoring with TK contacts
This fan speed controller offers the same speed control as the standard STR-4 series but with more options. One of them is monitoring thermal motor contacts or TK contacts. These contacts monitor the temperature inside the motor windings. Thanks to TK contacts, the motor is disabled if it overheats, preventing motor damage and activating the alarm output. This alarm output can be used to connect an external alarm module, such as a buzzer or a light. If your motor lacks TK contacts, you must bridge the two TK terminals of the controller to simulate normal motor temperature.
Automatic reset after power failure
The STRA4 series includes an automatic reset feature in the event of a power failure. When the power is restored after an outage, the connected motor will restart automatically. This is a convenient and time-saving feature, especially in applications where continuous motor operation is essential without human intervention in the event of a power interruption. This feature is particularly valuable in ventilation systems, ensuring a constant fan speed for proper air circulation and control.
Outputs for external devices
The unregulated output provides a fixed output voltage of 230 VAC when the motor is enabled. This output is always either ON (230 Volt) or OFF (0 Volt) and cannot be adjusted or regulated. It has a maximum current rating of 2 A. This unregulated output allows for the simultaneous operation of other devices or equipment that need to work in coordination with the fan. For example, you can connect an indicator lamp to this output to provide a visual indication when the fan is running. If you have air ducts with closing valves that need to be opened or closed when the fan is running, you can use this output to control their actuation.
Durable and cooling-optimized enclosure for indoor use
The enclosure of this controller is constructed from high-quality steel, offering robustness and excellent protection against impacts. It is rated with an IP54 protection level, effectively guarding against dust and water ingress. This fan speed controller is designed for indoor installation on walls or panels. To ensure optimal cooling and performance:
• Select a cool installation location.
• Avoid direct sunlight and high-temperature areas.
• Use the controller exclusively for indoor applications.
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