What is a TRIAC technology for fan speed control? A TRIAC is a three-terminal AC switch that can regulate AC loads at high voltage, unlike other silicon controlled rectifiers. It can show whether the applied gate signal is positive or negative. The gate is connected to both the N (neutral) and P (positive) regions, transferring a gate signal regardless of polarity. Unlike other devices, it does not have an anode and cathode (because, during an operation, they switch places: the anode becomes a cathode and backwards) and it has three terminals: main terminal 1 (MT1), main terminal 2 (MT2) and gate terminal (G). The TRIACs can be activated by applying a gate voltage higher than the break over voltage. Alternatively, it can be turned on by a 35-microsecond gate pulse.
How do TRIACs work?
The TRIACs principle of operation is often compared to two thyristors working in antiparallel, but the construction of TRIAC devices describes how they can perform a switching function over both parts of the AC waveform. This means, unlike standard thyristors, TRIACs can work with the current flowing in either direction so only one device needs to be used for many applications. It also means the device can perform conduction whether the polarity sent through the terminals is positive or negative. However, the sensitivity of the current required to trigger the device is highest when both terminals are with the same type of polarity.
As such, the four triggering modes of operation are defined as follows:
- I+ Mode: Terminal 2 current is +ve (positive), gate current is +ve
- I- Mode: Terminal 2 current is +ve, gate current is –ve (negative)
- II+ Mode: Terminal 2 current is -ve, gate current is +ve
- II- Mode: Terminal 2 current is -ve, gate current is -ve
Area of use
TRIACs are utilized in a wide range of applications, including light dimmers, speed controls for fans and other electric motors, and sophisticated computerized control circuits in a wide range of home small and large appliances. They may be used in both AC and DC circuits, but their initial purpose was to replace the need for two SCRs in AC circuits.
Typical, common application fields are:
- As a switching circuit – if the first switch is open, the device (with TRIACs) acts as an open switch.
- Fan speed control – TRIACs are often used in devices for AC fan speed control in AC circuits.
- Phase-controlled power delivery – they can control power delivery to various AC loads by adjusting the phase angle.
- Temperature control systems – TRIACs can be integrated in thermostats and heating control systems in order to help the process of regulating the temperature by adjusting the power delivered to heating pumps, duct, etc.
- To minimise the electrical noise – TRIACs can operate without mechanical movement, reducing the electrical noise, coming from the motor.
Sentera’s devices with TRIAC technology for fan speed control
Through the years, Sentera has developed many practical and innovative devices to ease the fan speed control in your house, factory, warehouse, etc. Our mission is to help our customer manage their heating and cooling or ventilation systems from a distance and, thus, to create ideal and healthy indoor environment, which leads to preserving physical structure of the body and mental health. In addition, we created different products, which could be integrated in whole installations or systems or operate by themselves – from typical sensors and sensor controllers to potentiometers, Internet gateways, transformer, variable or even electric fan speed controllers and etc. Most of our devices use the TRIAC technology of fan speed control, since this is a universal, yet innovative method for safe and precise speed regulation. Let us see these products:- AH2C1-6 series – The series feature electric heating controllers for single-phase or two-phase electric heating. The current is TRIAC-switched, which minimises wear and tear, while enhanced control accuracy reduces energy costs. Use the AH2A1-6 expansion module from the series to develop a reliable HVAC installation for your needs!
- DRE – This is an electronic fan speed controller, suitable for DIN rail mounting in electrical cabinets, featuring both regulated and unregulated output and perfect to control the speed of single-phase voltage controllable motors. All parameters are accessible via Modbus RTU communication protocol.
- DRX/Y series – The series includes electronic fan speed controllers for AC fans, suitable for DIN rail mounting with Modbus RTU communication.
- ECMF8 – This is an HVAC controller for EC fans or variable fan speed controllers. The device could be used as a single or dual ventilation control, as it requires a specific firmware, which you can download via SenteraWeb.
- EVS/S series – The EVS/-S series features AC fan speed controllers for single-phase voltage controllable motors and Modbus RTU communication.
- GTE*DM series - The GTE controller automatically regulates the speed of single-phase voltage controllable motors, according to the measured temperature values and features a Modbus RTU communication.
- GTE*DT series - The GTE controller automatically regulates the speed of single-phase voltage controllable motors, according to the measured temperature values and it has an integrated Schuko socket for motor connection and a PT500 probe input.
- GTEE1 series – These controllers automatically regulate the speed of single-phase voltage controllable motors according to the measured temperature values and controls a heater according to a temperature set point.
- GTT series - The series feature transformer fan speed controllers used to regulate the speed of single-phase voltage controllable motors in automatic or manual mode (in five steps) according to the temperature by varying the output voltage according to the measured temperature.
- ITR/S – These electronic fan speed controllers regulate the speed of single-phase voltage controllable motors by varying the supplied voltage. They feature an internal trimmer for minimum speed adjustment and an unregulated output for valve, lamp or damper connection.
- LTV – This potentiometer provides a stepless output signal to control fans with EC motors and it is used as an in-put device for controllers.
- LTX/-Y – These controllers provide an option for manual regulation of the speed of single-phase, voltage controllable motors (EC) by varying the supply voltage through phase-angle control.
- MTP – The purpose of MTP is to regulate the speed of standard fans with EC motors and provide an infinitely variable output signal between two internally selectable positions: Vmin and Vmax.
- MTV – These potentiometers are used to provide a stepless output signal for fan speed control.
- MTX/-Y – The MTX and MTY series of TRIAC-based variable fan speed controllers are used to regulate the speed of voltage controllable motor manually through phase angle control.
- MVS/S – Both series feature electronic fan speed controllers, suitable for DIN rail mounting. They feature a Modbus RTU communication, option for remote control, adjustable OFF level, minimum and maximum speed adjustment and time-limited motor operation.
- RDCZ9 – HVAC controllers for regulating the fan speed of AC voltage controllable fans, lighting systems and other. They feature a wide supply voltage range and a variable control output signal between an adjustable minimum and maximum level.
- RTR – These are transformer fan speed controllers that regulate the speed of single-phase voltage controllable motors by varying the output voltage in steps.
- RTVS8 – The series features transformer fan speed controllers for single-phase voltage controllable motors. They regulate the speed of the fan in five steps by varying the output voltage.
- SC2/A – Fan speed controllers with day or night operating mode. They are intended for single-phase voltage controllable motors. The SC2A1 series has external TK monitoring, while the SC2 – does not.
- SD* -DT – Series of AC fan speed controllers for manual regulation of the speed from low to high (SDY) and from high to low (SDX). The devices in this series are suitable for surface and inset mounting and use TRIAC technology of regulating fan speed.
- SDP – Intended for precise regulation of the speed of standard EC fans, damper actuator, AC fan speed controllers and frequency inverters. Suitable for a variety of applications where a variable control signal is required.
- SER-1 series – These fan speed controllers can regulate the speed of single-phase voltage controllable motors by adjusting the output voltage only in five steps. They also feature an emergency button for smoke extraction.
- SFPR1 series – These transformer speed controllers are intended for precise regulation of the speed of single-phase voltage controllable motors, as they adjust the output voltage. They feature TK monitoring for thermal motor protection and an input for remote start/stop.
- ST2R – Two-speed transformer controllers for single-phase voltage controllable motors. The devices are equipped with autotransformers, built-in clock, digital timer and a LCD display.
- STRA1 and STR1 series of fan speed controllers are intended for manual control of single-phase voltage controllable AC fans. The devices of the STRA1 series have an external TK function.
- STRS1 - 5-step transformer fan speed controller for single-phase motors. The fan speed can be adjusted using the rotary switch on the front cover and the series features a TK monitoring.
- STTA – The series features transformer fan speed controllers, intended for single-phase voltage controllable motors. They vary the output voltage and control the speed in five steps.
- STVS1 and STVS4 series – 5 step fan speed controllers, intended for single- or three-phase voltage controllable motors. They are equipped with autotransformers and feature TK monitoring for thermal motor protection.
- TVSS5 - The devices in this series control the speed of three-phase voltage controllable electric motors via an input control signal. They have Modbus RTU communication and thermal contacts to provide overheating protection of motors.
In conclusion, the TRIAC fan speed control technology remains the best choice for a precise control of the speed, as in the same time protects the motor from overheating and wear out of the components of the motor. For easy remote monitoring and control of the connected devices, you can use your own created HVAC installation on the Sentera cloud platform – SenteraWeb. Subscribe to our social media platform for more news: