EU declaration conformity
Fan speed controller | TK monitoring | remote start-stop | 3,5 A
Product description
Transformer fan speed controller with five speeds designed for single-phase motors featuring thermal contacts. The maximum motor current, when combined, is 3,5 A.
The rotary switch with an OFF position can be used to adjust the fan speed. The digital inputs allow for the remote enabling or disabling of the motor. In the event that the motor overheats, the TK monitoring function deactivates it. The motor will start up automatically after a power outage. External devices can be controlled by the alarm and unregulated outputs to produce alerts or verify regular operation.
By lowering the motor voltage in five steps using autotransformers, the fan speed is controlled. This method produces an output voltage with a perfect sinusoidal form, ensuring silent motor running.
The enclosure has an IP54 rating for protection against moisture, dirt, and dust intrusion and can be surface mounted.
Documents
Additional specifications and description
5-step fan speed controller with extra features
The fan speed can be set via the rotary switch with 5 positions and OFF position to switch off the motor. This speed controller is only suitable for voltage-controllable motors. This is because the autotransformer technology reduces the motor voltage and the fan speed in 5 steps. If you are not sure whether your motor is voltage controllable, it is best to contact the motor manufacturer. Autotransformer technology is very reliable and robust. It generates a motor voltage with a perfect sinusoidal shape. This results in exceptionally quiet motor operation and extended service life. A special impregnated coating reduces the electrical noise from the autotransformers.
![STRA1-35L22 with air curtain](/en/files/article/image/description/stra1-35l22/control-fan-speed-air-curtain-tk.jpg)
Fans with TK contact can be thermally monitored
This fan speed regulator offers the same speed control as the standard STR-1 series with some extra options. One of these options is the possibility to monitor thermal motor contacts. TK or thermal contacts monitor the temperature inside the motor windings. In case of the motor overheating, the TK monitoring function will disable the motor to prevent motor damage and will activate the alarm output. If the motor is not equipped with TK contacts, both TK terminals of the controller can be bridged to simulate a normal motor temperature.
Inputs offer remote control possibilities
Furthermore, the STRA1 series offers more control options thanks to extra inputs. Via these inputs, the motor can be remotely enabled or disabled. This can be used, for example, to connect a smoke alarm to the input. If a smoke alarm occurs, the motor will be disabled - regardless of the status of the other input. In this way, spread of the toxic smoke gases through the ventilation system can be slowed down. Another example is to connect a door contact to control an air curtain. When the door is opened, the door contact activates the air curtain via the input of the STRA1 controller. The air curtain will then run at a fixed speed, set via the rotary switch.
Outputs to control external devices
The extra, unregulated output (230 VAC) is active when the motor is enabled. This output is either ON (230 Volt) or OFF (0 Volt), so it cannot be 'regulated'. Therefore, it is called an ‘unregulated output'. The maximum current of this output is 2 A. This output can be used to control an indicator lamp, open the closing grids of the air ducts, activate lighting, etc. The device connected to this output will operate simultaneously with the fan.
Auto reset after power failure
In case of a power failure, this controller will automatically reset itself. When the power is restored, the motor will restart automatically. With standard fan speed controllers, after a power failure, the rotary switch must be turned manually to the OFF position and then back to the desired speed position. This is not necessary with the STRA1 series.
Enclosure for indoor wall mounting
Make sure that the fan speed controller can sufficiently cool. Preferably install it in a cool place, best not in direct sunlight. The enclosure is designed and manufactured in-house. We use high-quality r-ABS VO (UL94) plastic. This material is flame extinguishing, very tough and offers good protection against impacts. It offers IP54 protection against the ingress of dust and water. This fan speed controller can be installed on a wall or panel indoors.
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