‘Not all drives are the same’ – 30 technical challenges addressed

The top tips eBook will consist of challenges that affect consultants, OEMs, system houses, facility managers and end-users. The challenges are a result of two decades of research, based on feedback from customers, observations of third-party installations and changes to legislations, regulations and standards. 

Carl Turbitt, ABB’s UK manager for HVAC drives, states that ‘what has become clear is that not all drives are the same. This is partly due to advances in hardware and software which means that today’s drives are very different to those that were written into specifications several years ago’. 

Today’s heating, ventilation and air conditioning (HVAC) applications can be driven with a variety of motor types from electronically commutated motors (ECMs), permanent magnet motors (PM), synchronous reluctance motors (SynRM) and induction motors. Yet users need to be extremely careful when selecting which type of motor can be used for their application.

ECMs, for example, are brushless DC motors that function using a built-in inverter and a magnetic rotor, and as a result are claimed to achieve greater efficiency in air-flow systems than other kinds of AC motors. The motors have a long life and are extremely quiet. However, they can be costly to buy and while the high efficiency offered by ECMs may be suitable for some applications, it is essential that the right motor technology is selected if unforeseen problems with harmonics, catching spinning loads and power loss ride through are to be avoided.

The cost-effective SynRM, for example, offers the same efficiencies as ECMs but without the aforementioned issues. A SynRM controlled properly in a well-designed system can achieve the specific fan powers, whilst being controlled by a traditional VSD that then brings all of the advantages associated with that drive such as: improved harmonic mitigation, adequate power drip ride through, fieldbus connectivity and built-in control features to enhance the application.

Among some of the other considerations when selecting a drive is that not all harmonic mitigation is the same, not all drives are right for outdoor use and not all drives achieve the EMC regulations when connected to a motor.

ABB has addressed many of these challenges by incorporating hardware and software changes in its new ABB HVAC drive, ACH580 - a variable-speed drive dedicated to the HVAC sector.