Fan speed controller: models, features and connection diagram

Fans are widely used in various fields of human activity. Devices can be found in residential and public premises, they are used to cool computers and laptops, they are installed in exhaust and supply and exhaust ventilation units and air conditioning systems. However, the operation of the device at full capacity is not always necessary and expedient. Therefore, to limit the rotational speed of the blades, special devices are used - fan speed controllers.

A fan speed controller is a small device that can reduce or increase the rotational speed of the working shaft. The controllers are connected to the fans according to a certain scheme and are controlled using a manual method or automation. Automatic models are closely interconnected with other devices of the ventilation unit, for example, with sensors that detect temperature, pressure, movement, as well as with photo sensors and devices that detect humidity. The data from these devices are transmitted to the controller, which, on the basis of them, selects a suitable speed mode.

Mechanical models are manually operated. The rotation speed is controlled by a wheel mounted on the device body. Often, controllers are mounted into the wall according to the principle of a switch, which makes their use convenient, and allows you to smoothly change the number of revolutions at any time. The devices are available in a wide power range and are capable of operating from both 220 and 380 V.

During constant operation of the fan at maximum speed, the resource of the device is exhausted quickly enough. As a result, the power of the device is noticeably reduced, and the device fails. This is due to the fact that many parts are not able to maintain such a rhythm, which is why they quickly wear out and break. To limit the speed of rotation of the blades and increase the life of the fan, a speed controller is built into the air handling unit.

In addition to saving operating resources, controllers perform an important function of reducing noise from operating ventilation systems. So, in office premises, where there is a large accumulation of office equipment, the noise level can reach 50 dB, which is due to the simultaneous operation of several devices, the fans of which operate at maximum speed. In such conditions, it is difficult for a person to tune in to a working mood and concentrate.

The way out of this situation is to equip ventilation units with speed regulators. Another compelling argument in favor of using regulators is economical energy consumption. As a result of a decrease in the number of revolutions and a decrease in the total power, the fan starts to consume less energy, which has a positive effect on the budget.

The principle of operation of the controller is to change the voltage that is supplied to the winding of the fan motor. There are more expensive models that can regulate the speed of rotation by changing the frequency of the current.However, the cost of such products often exceeds the cost of the fan itself, which makes their installation impractical.

Rotational speed controllers are used almost everywhere where there is an air handling unit. Regulators are indispensable for arranging ventilation systems in gyms, offices and cafes. Often such devices can be found in individual climate control systems. Air conditioners operating for space heating are also equipped with controllers - powerful transformer devices capable of adjusting the impeller speed.

However, the most common installation options for the controller are computers and laptops. Regulators can significantly reduce fan noise and are often equipped with additional features such as backlighting, temperature sensor and audible alarm for shutdown. Some models are equipped with a display.

There are several types of fan speed limiters.

The essence of the operation of this device lies in the fact that the winding of the device is branched, therefore, in the process of connecting to the branches, the fan receives a slightly reduced voltage. With the help of a special switch, one or another fan is connected to the desired section of the winding, and the speed of its rotation decreases. Simultaneously with this, electricity consumption is reduced, which leads to an overall resource saving.

The device is adjusted using a special knob equipped with a stepped scale with 5 positions. The advantages of the models are their reliability and long service life. The disadvantages include a fairly large control unit, which is not always convenient when placing the device in confined spaces, as well as the impossibility of smooth switching. However, when temperature sensors and a timer are connected, the switching of rotation speeds can be automated.

The essence of the operation of such devices is somewhat different from the principle of operation of previous models. The device is equipped with a transistor circuit and is capable of modulating pulses, while smoothly changing the voltage. The strength of the voltage directly depends on the frequency of the pulses and the pauses between them. So, with short impulses and long pauses, the voltage will be much lower than with long impulses and short pauses.

The advantages of this controller are small size and comfortable cost. The disadvantages include the short length of the connecting cable. This necessitates a separate location of the unit from the control handle and its placement closer to the fan. Electronic models are used in large factories in combination with powerful ventilation units. They are overload resistant and capable of continuous operation for a long time.

This type of regulator is the most common. The device is used to connect to a single-phase AC fan, however, it can work with a constant one. When the device is operating, each of the thyristors lowers the output voltage, thereby reducing the number of revolutions per minute. The advantages of the devices are low cost, low weight and the ability to reduce the number of revolutions to almost zero.

You can connect the speed controller to the fan with your own hands. To do this, you must carefully read the instructions and observe a number of safety measures when working with electrical appliances.Depending on the type of construction and the type of ventilators being serviced, the controllers can be installed on the wall, inside the wall, inside the ventilation unit or in a free-standing cabinet of the “smart home” system. Wall and in-wall regulators are fixed with screws or dowels, depending on the dimensions and weight of the device. Fasteners are usually included in the kit along with the device connection diagram.

The connection diagrams for the models may differ, however, there are still general patterns and sequence of actions. First, the controller must be connected to the cable that supplies current to the fan. The main purpose of this stage is to separate the "phase", "zero" and "earth" wires. Then connect the wires to the input and output terminals. The main thing in this case is not to mix up the wires in places and connect according to the instructions. In addition, check that the cross-section of the power cable and connection matches the maximum allowed voltage of the connected device.

When connecting the speed controller to laptop fans with a voltage of 12 volts, it is necessary to find out the maximum permissible temperatures of the device parts. Otherwise, you can lose your computer, which from overheating will fail the processor, motherboard and graphics card. When connecting the controller to office equipment, you must also strictly follow the instructions. If you need to connect several fans at once, it is better to purchase a multi-channel regulator, since some models are capable of servicing up to four fans at the same time.

Fan speed controllers are an important multifunctional device. They protect equipment from overheating, extend the life of electric fan motors, save energy and significantly reduce the noise level in rooms. Due to their efficiency and practicality, devices are gaining more and more popularity and growing consumer demand.

How to make a fan speed controller with your own hands, see below.