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Light grey plastic enclosure, blue label, knob
Light grey plastic enclosure, blue label, knob
Light grey plastic enclosure, blue label, knob
Light grey plastic enclosure, three cable glands
Light grey plastic enclosure, blue label, knob
Light grey plastic enclosure

Fan speed controller | TK monitoring | remote start-stop | 7,5 A

Product description

5-speed transformer fan speed controller for single-phase motors with thermal contacts. The (combined) maximum motor current is 7,5 A. The fan speed can be set via the rotary switch with OFF position. The motor can remotely be enabled or disabled via the digital inputs. The TK monitoring function deactivates the motor in case of overheating. After a power failure, the motor will automatically restart. The alarm output and the unregulated output can control external devices to generate alerts or to confirm normal operation. The enclosure can be surface mounted and offers an IP54 protection against ingress of dirt, dust and moisture. The fan speed is regulated by reducing the motor voltage via autotransformers in 5 steps. This technology generates an output voltage with perfect sinusoidal shape, guaranteeing quiet motor operation.

Article code
Advanced fan speed control - TK monitoring
Current stock
6 U.
Factory lead time
5 Day(s)

Additional specifications and description

5-step fan speed controller with extra features

This fan speed controller has a rotary switch with 5 positions, through which the fan speed can be set. One of the positions is 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. 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.
 STRA1-75L22 with air curtain
Fans with TK contact can be thermally monitored
This fan speed regulator offers the same speed control as the standard STR-1 series. However, it comes 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 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 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 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. Because this output is either ON (230 Volt) or OFF (0 Volt), it is called ‘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 
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.
Enclosure for indoor wall mounting
Make sure that the fan speed controller can cool sufficiently. 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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