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EU declaration conformity
400 V transformer fan speed controller | TK monitoring | 2,5 A
Product description
Transformer fan speed controller with thermal connections for a 400 V motor. The maximum motor current (combined) is 2.5 A.
The fan speed may be adjusted using the rotary switch on the front panel. In the event of overheating, the TK monitoring feature shuts the motor.
The fan speed is controlled in five stages by lowering the motor voltage. The exact sinusoidal form of the output voltage ensures silent motor running.
The enclosure is surface mountable and provides IP54 protection against dirt, dust, and moisture entry. The power supply voltage is 400 volts.
Additional specifications and description
General
The STRS4-25L40 utilizes transformer-based fan speed control technology, which refers to the use of transformers in controlling the speed of electric fans. Traditional electric fans typically have a few pre-set speed levels controlled by mechanical switches / knobs. Transformer-based control systems provide an efficient and flexible way to regulate fan speed. The unit includes a transformer, which transfers electrical energy between circuits. It consists of primary and secondary windings wound around a magnetic core.
The primary purpose of using a transformer in fan speed control is to vary the voltage supplied to the fan motor. By adjusting the voltage, the rotational speed of the motor can be altered, thereby changing the fan speed. The transformer is equipped with multiple taps or terminals along the primary winding. These taps allow for different voltage levels to be selected, which correspond to various fan speed settings, in this case the output voltages are: 130, 180, 230, 300 and 400 VAC. The control mechanism is a 5-step rotary switch enabling users to select the desired fan speed setting. Each step corresponds to the one of the output voltages. When a particular speed setting is selected, the control mechanism adjusts the transformer taps, thereby changing the voltage supplied to the fan motor.
Efficiency
Compared to other speed control methods, transformer-based control systems are generally more energy-efficient. By adjusting the voltage supplied to the motor, power wastage is minimized, resulting in better overall energy utilization. What is more, transformer-based fan speed control produces a motor voltage with a perfect sine shape. This results in smoother motor operation and reduces electrical noise, leading to exceptionally silent motor operation. Also, the autotransformers incorporated in Sentera’s controllers are impregnated with a special coating which contributes further to the quieter motor operation.
Extra connections
The series features TK or contacts for monitoring thermal motor protection. Electric motors generate heat during operation, and excessive heat can damage the motor or pose a safety risk. To prevent overheating, motor manufacturers incorporate thermal overload protection mechanisms. Thermal contacts are located within the motor windings or housing. They are designed to detect the temperature of the motor. When the temperature exceeds a predetermined threshold, the thermal contacts change their state. They can either open the circuit to interrupt power to the motor, or in some cases, they can close a circuit to activate an alarm or signal the need for maintenance. After a thermal overload event, the motor contacts need to be manually reset or automatically reset once the temperature returns to a safe level. This ensures that the motor remains protected and prevents immediate reactivation if the cause of the overheating is not resolved.
Also, the STRS4 controller features an additional, unregulated output of 230 VAC. This output becomes active when the fan is running. This extra output can be utilized to control various external devices or components such as a run-indicator or a damper. For example, you can connect a run indicator to this output to indicate the operational status of the fan. When the fan is activated, the run indicator will be powered and display that the fan is running. Conversely, when the fan is deactivated, the run indicator will be unpowered, indicating that the fan is not in operation.
Surface mounted enclosure
The STRS4-25L40 features a steel enclosure with paint coating resistant to external mechanical impacts. It can withstand accidental hits or other physical forces without compromising its structure or the items inside. This is particularly important for ensuring the protection of the enclosed components. The ingress protection rating of IP54 guarantees that the enclosures are designed to provide a high level of protection against dust and water ingress, they are effectively sealed against dust particles and can withstand water splashes from any direction, making them suitable for moderately harsh environments.
The primary purpose of using a transformer in fan speed control is to vary the voltage supplied to the fan motor. By adjusting the voltage, the rotational speed of the motor can be altered, thereby changing the fan speed. The transformer is equipped with multiple taps or terminals along the primary winding. These taps allow for different voltage levels to be selected, which correspond to various fan speed settings, in this case the output voltages are: 130, 180, 230, 300 and 400 VAC. The control mechanism is a 5-step rotary switch enabling users to select the desired fan speed setting. Each step corresponds to the one of the output voltages. When a particular speed setting is selected, the control mechanism adjusts the transformer taps, thereby changing the voltage supplied to the fan motor.
Efficiency
Compared to other speed control methods, transformer-based control systems are generally more energy-efficient. By adjusting the voltage supplied to the motor, power wastage is minimized, resulting in better overall energy utilization. What is more, transformer-based fan speed control produces a motor voltage with a perfect sine shape. This results in smoother motor operation and reduces electrical noise, leading to exceptionally silent motor operation. Also, the autotransformers incorporated in Sentera’s controllers are impregnated with a special coating which contributes further to the quieter motor operation.
Extra connections
The series features TK or contacts for monitoring thermal motor protection. Electric motors generate heat during operation, and excessive heat can damage the motor or pose a safety risk. To prevent overheating, motor manufacturers incorporate thermal overload protection mechanisms. Thermal contacts are located within the motor windings or housing. They are designed to detect the temperature of the motor. When the temperature exceeds a predetermined threshold, the thermal contacts change their state. They can either open the circuit to interrupt power to the motor, or in some cases, they can close a circuit to activate an alarm or signal the need for maintenance. After a thermal overload event, the motor contacts need to be manually reset or automatically reset once the temperature returns to a safe level. This ensures that the motor remains protected and prevents immediate reactivation if the cause of the overheating is not resolved.
Also, the STRS4 controller features an additional, unregulated output of 230 VAC. This output becomes active when the fan is running. This extra output can be utilized to control various external devices or components such as a run-indicator or a damper. For example, you can connect a run indicator to this output to indicate the operational status of the fan. When the fan is activated, the run indicator will be powered and display that the fan is running. Conversely, when the fan is deactivated, the run indicator will be unpowered, indicating that the fan is not in operation.
Surface mounted enclosure
The STRS4-25L40 features a steel enclosure with paint coating resistant to external mechanical impacts. It can withstand accidental hits or other physical forces without compromising its structure or the items inside. This is particularly important for ensuring the protection of the enclosed components. The ingress protection rating of IP54 guarantees that the enclosures are designed to provide a high level of protection against dust and water ingress, they are effectively sealed against dust particles and can withstand water splashes from any direction, making them suitable for moderately harsh environments.
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