EU declaration conformity
Fan speed controller | TK monitoring | remote start-stop | 13 A
Transformer fan speed controller with five speeds designed for single-phase motors featuring thermal contacts. The maximum motor current, when combined, is 13 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 technology ensures silent motor operation by producing an output voltage with an ideal sinusoidal shape.
The enclosure has an IP54 rating for protection against moisture, dirt, and dust intrusion and can be surface mounted.
Additional specifications and description
5-step fan speed controller with extra features
The rotary switch of this fan speed controller has five positions, each corresponding with a different fan speed. With one of the positions the motor can be switched off directly: the OFF position. The autotransformer technology reduces the fan speed and motor voltage in 5 steps. Therefore, this speed controller is only suitable for voltage-controllable motors. If you are not sure if 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. Any remaining electrical noise from the autotransformers is further filtered by the special impregnated coating.
Inputs offer remote control possibilities
Furthermore, the STRA1 series offers more control options thanks to its 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. The smoke alarm input will override the status of the other input. 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. Whenever the door opens, the door contact is triggered. It then activates the air curtain via the input of the STRA1 controller. The air curtain will run at a fixed speed, set via the rotary switch.
Fans with TK contact can be thermally monitored
This fan speed controller offers the same speed control as the standard STR-1 series, but 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. Thanks to the TK, if the motor overheats, the motor will be disabled to prevent motor damage and the TK will activate the alarm output. This alarm output can be used to connect an external alarm module, such as a buzzer or a light. If the motor is not equipped with TK contacts, both TK terminals of the controller must be bridged to simulate a normal motor temperature.
Auto reset after power failure
This controller will automatically reset itself in case of a power failure. 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, but not with the STRA1 series.
Outputs to control external devices
The extra, unregulated output (230 VAC) is active when the motor is enabled. This output is always either ON (230 Volt) or OFF (0 Volt). It is called ‘unregulated output', because the output value cannot be regulated. 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.
Enclosure for indoor wall mounting
Make sure that the fan speed controller can sufficiently cool. For this reason, preferably install it in a cool place, away from direct sunlight. The enclosure is made out of high quality steel. This material is 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.