Manual control for AC fans
The transformer is an electromagnetic conversion device in which the electrical energy received by its primary winding is first converted into magnetic energy, which is re-converted into electrical energy in other circuits – secondary winding. Thus, the primary and secondary windings are not connected electrically, but coupled magnetically.
The transformers used for these transformer fan speed controllers are step-down transformers, which means that the secondary voltage is lower than the primary voltage.
The transfer of electrical energy between two circuits takes place through a transformer without the use of moving parts; a transformer therefore has higher efficiency and lower maintenance cost than rotating electrical machines.
These transformers reduce the voltage to the controlled device, i.e. the AC fan motor, to standardized voltage levels. Depending on the product series and versions, different output voltages are available to suit customer needs.
Transformers have made AC systems flexible because the various parts and equipment of the power system can be operated at economical voltage levels with suitable voltage ratios.
Why opt for this type of controllers
Simplicity! With manually operated transformer fan speed controllers, you set the desired fan speed based on your comfort or specific requirements using the integrated knob on the enclosure.
These controllers are straightforward to connect, use and maintain, contributing to their reliability. Their simplicity reduces the likelihood of technical issues and makes them easy for end users to operate without the need for much technical knowledge. Users have direct control over the fan speed and can customize the airflow based on personal comfort preferences or specific environmental conditions. With fewer electronic components compared to automated systems, a manually operated controller using a rotary knob reduces the likelihood of technical failures, contributing to the overall durability of the HVAC system.
Understanding product versions
As standard, the product series name is followed by the rated current and the last three characters of Sentera’s transformer fan speed controllers are a letter + two digits. For example, the complete name of a controller is STR-1-35L22. This means that the product series is STR-1, its rated maximum current is 3,5 A. The letter “L” stands for “Low”, meaning, the controllers are operated from low speed to high speed. Currently, depending on the output voltages, we offer the following versions:
L10 output voltages: 0, 80, 110, 14, 170 and 230 VAC
L20 output voltages: 0, 80, 100, 120, 140, 170 and 230 VAC
L22 output voltages: 0, 80, 110, 140, 170, 190 and 230 VAC
L25 product versions feature two transformers – one for low speeds and another one for high speeds. The output voltages are: 0, 120, 150, 170, 190 and 230 VAC for high speeds and 0, 80, 100, 120, 150 and 170 VAC for low speeds.
The transformer controllers have five output steps, but sometimes there are more than five output voltages available. These devices allow for change of the internal wiring in order to select the most appropriate output voltages according to the customer needs.
Moreover, because manually operated fan speed controllers have become so popular amongst customers, besides the basic standard series, there are versions featuring an external knob connection for remote motor control, TK monitoring functionality, an emergency button for smoke evacuation, a day and night mode, remote start-stop function and last but not least sensing input for gas flow control.
The controllers up to 7,5 A are available in plastic enclosure, while the models above 7,5 A are available in a metal enclosure.
The controllers up to 7,5 A are available in plastic enclosure, while the models above 7,5 A are available in a metal enclosure.