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EU declaration conformity
Fan speed controller | TK monitoring | remote start-stop | 20 A
Product description
5-speed transformer fan speed controller for single-phase motors with thermal contact. The (combined) maximum motor current is 20 A.
The fan speed is set with the rotary switch with OFF position. The motor can be remotely switched on or off via digital input
The TK monitoring function stops the motor in case of overheating. The motor restarts automatically after a power failure. Alarm and uncontrolled outputs can be used to control external devices to issue warnings or check normal operation.
The fan speed is controlled by a five-stage reduction of the motor voltage through an autotransformer. This technology results in a perfectly sinusoidal output voltage and guarantees quiet motor operation.
The metal enclosure can be surface mounted and is IP54 rated against dirt, dust and moisture.
Additional specifications and description
5-step fan speed controller with extra features
Via the rotary switch with 5 positions, the fan speed can be set. There is also an OFF position to switch off the motor. 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 and 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.
Fans with TK contact can be thermally monitored
This fan speed regulator has some extra options, but offers essentially the same speed control as the standard STR-1 series. One of these is the possibility to monitor thermal motor contacts. TK or thermal contacts monitor the temperature inside the motor windings. In case of motor overheating, the TK monitoring function will disable the motor to prevent motor damage and activate the alarm output. If the motor is not equipped with TK contacts, both TK terminals of the controller must be bridged to simulate normal motor temperature.
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 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. Another example is 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.
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.
Outputs to control external devices
The extra 230 VAC unregulated output is active when the motor is enabled. This output is called ‘unregulated output' because it is either ON (230 Volt) or OFF (0 Volt). 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 cool sufficiently. 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.
Via the rotary switch with 5 positions, the fan speed can be set. There is also an OFF position to switch off the motor. 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 and 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.
Fans with TK contact can be thermally monitored
This fan speed regulator has some extra options, but offers essentially the same speed control as the standard STR-1 series. One of these is the possibility to monitor thermal motor contacts. TK or thermal contacts monitor the temperature inside the motor windings. In case of motor overheating, the TK monitoring function will disable the motor to prevent motor damage and activate the alarm output. If the motor is not equipped with TK contacts, both TK terminals of the controller must be bridged to simulate normal motor temperature.
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 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. Another example is 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.
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.
Outputs to control external devices
The extra 230 VAC unregulated output is active when the motor is enabled. This output is called ‘unregulated output' because it is either ON (230 Volt) or OFF (0 Volt). 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 cool sufficiently. 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.
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