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An inverter, also known as a variable speed drive (VSD) or variable frequency drive (VFD), controls the speed of an electric motor by varying the voltage and frequency supplied to it.
An inverter allows a motor to run at the speed required by the application instead of continuously running at full speed. This can reduce energy consumption, lower running costs and, depending on the application, help an inverter pay for itself over time.
Inverters are commonly used with fans, pumps, HVAC systems, conveyors, mixers, extruders, and other industrial machinery.
An inverter is one part of the complete motor power train:
Whether you need an inverter depends on the motor, the application and whether variable speed, controlled starting and stopping, reversing or reduced energy consumption would be beneficial.
An inverter is an electronic motor control device installed between the electrical supply and the motor.
It changes the frequency and voltage supplied to the motor to control its speed. The inverter can also control how the motor starts, stops and, where configured and permitted by the application, changes direction.
A conventional motor connected directly to the mains generally runs at a fixed speed determined by its supply frequency, motor design, and load. An inverter allows the motor speed to be adjusted to match the requirements of the application.
For example, a conveyor may need to operate at different speeds depending on the production process. An inverter allows the motor speed to be adjusted without running the motor continuously at full speed.
Yes, an inverter can reduce energy consumption and running costs when a motor can operate at a lower speed rather than running continuously at full speed.
This is particularly important with centrifugal fans and pumps, where relatively small reductions in motor speed can produce significant reductions in power consumption.
Under the fan and pump affinity laws, reducing speed by 10% can reduce the theoretical power requirement by approximately 25%. The actual saving will depend on the motor, load, system, and operating conditions.
This means an inverter can offer more than motor speed control. If a fan or pump operates for long periods below full speed, the reduction in electricity consumption can provide a financial saving over the life of the equipment.
The potential return on investment depends on factors such as:
For applications with long operating hours and significant periods of reduced speed operation, the energy saving can make an inverter a worthwhile investment.
If you would like to find out whether an inverter could reduce energy consumption in your application, we can arrange an energy saving calculation.
The main reason for installing an inverter is to control motor speed. Variable speed control can also provide other benefits depending on the application.
An inverter allows the motor to operate at different speeds. This can be useful where the required output changes during operation.
For example, a ventilation system may not need to operate at full speed when there is less demand for airflow. A pump may also need to vary its flow rate rather than running continuously at full speed.
Running a motor at the speed actually required by the application can use less electricity than operating it continuously at full speed.
The potential saving is particularly significant for centrifugal fans and pumps with variable flow or airflow requirements.
An inverter can provide a controlled increase and decrease in motor speed instead of applying the full change in speed immediately.
This can reduce sudden changes in torque and mechanical stress on the motor and driven equipment.
An inverter can control the direction of motor rotation where the motor, drive and application are suitable for reversing.
This can be useful for applications such as conveyors and mechanical shredders.
An inverter may be suitable when you need to:
Typical inverter applications include:
An inverter is not automatically required for every electric motor. If a motor only needs to run at its normal fixed speed and does not require controlled starting, stopping, or reversing, a direct-on-line starter or another motor starting method may be more appropriate.
Choosing the correct inverter involves more than matching its kW rating to the motor.
The main factors to check are:
Check the motor's rated power in kW and select an inverter that is suitable for the motor and its load.
The inverter should also be selected according to the manufacturer's current and application requirements, rather than relying on the kW rating alone.
Check the electrical supply available and the motor's supply requirements.
TECDrive inverters are available for both single phase and three phase applications, with different power ranges depending on the inverter type.
Consider where the inverter will be installed and the level of protection required.
For installation inside a control panel, an IP20 inverter is normally used. For suitable direct machine mounting and applications requiring a higher enclosure rating, an IP66 inverter may be more appropriate.
Consider what the motor is driving.
Fans and pumps have different load characteristics from conveyors, mixers, and other industrial machinery. TECDrive inverters have Industrial, Pump and Fan application modes to simplify setup for these applications.
Consider how the motor needs to be operated.
You may need:
This will help determine which inverter and accessories are suitable.
TECDrive inverters use sensorless vector control and support a range of motor types, including IE2, IE3 and IE4 induction motors, PM AC motors, BLDC motors, and SynRM motors.
Sensorless vector control provides motor control without requiring an encoder. Always check the specifications of the individual inverter to confirm compatibility with the motor you intend to use.
The correct enclosure rating depends on where the inverter will be installed.
IP20 inverters are designed for installation inside a suitable control panel.
TECDrive IP20 models have a compact footprint with DIN rail and keyhole mounting options. The electrical supply connects at the top and the motor supply connects at the base.
TECDrive IP20 inverters are available in:
An IP20 inverter should not be treated as a standalone weatherproof or washdown enclosure. It needs to be installed in an enclosure that provides the protection required by the installation.
IP66 inverters are designed for direct machine mounting and provide a higher level of protection against dust and water ingress than IP20 models.
TECDrive IP66 inverters are available as switched and unswitched versions.
The IP66 models use polycarbonate enclosures selected for resistance to UV, greases, oils, and acids. They also have a coated heatsink for use in demanding environments, including applications where high pressure washdown is required.
The suitability of any inverter for a particular washdown application will depend on the complete installation and the conditions it will be exposed to.
TECDrive IP66 inverters are available in:
TECDrive IP66 switched inverter controls
TECDrive IP66 inverters are available as switched or unswitched models.
An unswitched inverter does not have the built-in local operating controls found on the switched version. It can be suitable where the inverter is controlled from elsewhere in the installation.
A switched inverter adds local controls directly to the drive. TECDrive switched models include:
This allows the operator to adjust motor speed and control the motor's direction and operation locally.
The lockable mains disconnect/isolator also provides a local means of disconnecting the inverter from the mains supply for maintenance and servicing, subject to the site's isolation procedures.
A switched model can therefore be useful when the machine operator or maintenance engineer needs convenient access to the main motor controls at the inverter.
TECDrive inverters are designed for straightforward commissioning. They have 14 basic parameters covering the main setup requirements, with additional parameters available for more advanced configuration.
Application macros provide preset settings for common types of operation.
Industrial Mode is intended for typical industrial loads and applications such as conveyors, mixers, and treadmills.
Pump Mode provides functions for pump applications, including dosing pumps, borehole pumps, transfer pumps, swimming pools and spas, and fountains.
Fan Mode is intended for fan and HVAC applications such as air handling units, ventilation fans, circulation fans, air curtains, smoke extraction, and kitchen extraction.
Selecting the appropriate application mode can simplify commissioning by providing settings suited to the type of load being controlled.
TECDrive inverters include a range of built-in control and communication features.
Modbus RTU and CANopen are included as standard, allowing compatible inverters to communicate with control and automation systems.
Bluetooth connectivity provides wireless communication with compatible devices and accessories.
Internal PI control can be used for applications that need the inverter to respond to changes in a process variable.
Dual analogue inputs provide connection options for analogue control signals.
Internal Category C1 EMC filter is included in every TECDrive inverter. Having the filter built into the drive can reduce the need for a separate external EMC filter, depending on the installation and EMC requirements.
Operation up to 50°C allows the inverter to operate at ambient temperatures up to 50°C, subject to the manufacturer's conditions and any applicable derating.
Sensorless vector control provides motor control without the need for an encoder and allows TECDrive inverters to control a range of compatible motor types.
TECDrive inverters can be used with motors from different manufacturers, provided the motor and inverter specifications are compatible.
TECDrive offers accessories for commissioning, configuration, and remote operation.
The Optistick Smart is a commissioning tool that can copy, back up and restore drive parameters.
It provides a Bluetooth interface to a PC running OptiTools Studio or to the OptiTools app on a smartphone. It also has onboard NFC (Near Field Communication) for quick data transfer.
This can be useful when settings need to be transferred between drives or backed up for future use.
The Optipad is a remote keypad with an OLED display for setting up and operating a compatible inverter.
It uses a standard RJ45 8-way connector as its electrical interface and is supplied with an RJ45 cable.
The Optiport is a remote keypad with an OLED display and is supplied with an RJ45 cable for connection to the inverter.
Before choosing a TECDrive inverter, check:
The inverter should be selected for the motor, load, and installation, not simply by choosing a model with the same kW rating as the motor.
If you are unsure which TECDrive inverter is suitable, check the individual product specifications or contact us for help selecting the appropriate model.
All TECDrive inverters come with a 1 year warranty as standard.
When a TECDrive inverter is purchased together with a TEC motor, the warranty is extended to 2 years.
This gives you an additional reason to consider a TEC motor and TECDrive inverter together when specifying a complete motor and drive package.
