A.C variable speed drives have been around for many years, but they are still breaking new ground and finding new uses throughout all sectors of industry.  According to Matt Handley, Mitsubishi Electric’s Product Manager for Drives, in addition to optimising the energy saving capabilities of their models, the leading manufacturers are improving integration, safety and more.

Networking and precision motion

Discrete parts manufacturing, process control, building management, and almost every new technical system has become more intelligent. Various parts of the system communicate with one another to optimise overall performance.

This requires that individual devices, such as drives, PLCs, HMIs, and sensors can send and receive data – and act intelligently on it. For instance, modern drives can receive a temperature signal and adjust the speed of a ventilation fan or water pump accordingly utilising built in PID controllers.

Other drives may work with counters or timers to control parts production. A motion detector in a building’s security system could work with a drive to close a shutter, turn down the air conditioning, open a car park gate, etc.

Modern drives are offering ever greater levels of motor shaft control and this is especially important when they are used in motion control applications. A good example of this is when they are networked together with servo drives over specialist high speed fibre optic networks such as SSCNet.

The servos will control the high precision axes in the system, and they will be communicating with the inverter drives on the general axes to improve overall system performance. It is worth noting that a top-of-the-range drive can enhance an industrial motor’s dynamic performance to near servo capability, so is suitable for axes where some extra precision is required.

Standalone drive systems

A very interesting trend in drives engineering is the rise of standalone systems. The water industry, other utilities, agriculture, environmental monitoring, security and many other sectors are characterised by the fact that they often have systems that are physically remote from one another. Until a few years ago, accepted wisdom was to keep these as simple as possible.

However, attitudes are changing, driven partly by a desire to reduce their energy consumption and partly the need for remote interrogation. Drives play a major part in this offering a series of ‘keep on running functions and drives designers are rising to the challenge of developing systems that can run intelligently but unattended for perhaps months at a time.

Integrated safety

A more recent trend is Integrated Safety.  Plant and machinery can be dangerous to life and limb and in addition to operator training, physical guards and barriers, the onus is on plant operators to ensure the safety of their personnel-however silly they sometimes behave.

Changes to the machinery directive have meant that machinery designers now have to design in more rigorous safety systems and carry out more in depth risk assessments. Inverter drives can be a key component in a machine and so the move for drive manufacturers to embed safety functionality into their drives has grown. This safety functionality is equally important if the machine is redesigned. Embedded safety features means it is possible to cut down on components and so reducing overall machine build costs.

See Matt’s article in full

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