Completing most systems requires a variety of electromechanical products including switches, relays, motors, protection, cooling technologies and more. These well-established products face challenges on many fronts, including:
Greater Efficiency
The need to improve efficiency in motor controlled systems such as air conditioning (AC) systems and washing machines has increased the focus on brushless dc motors replacing brush motors. Today, using a brushless dc motor and replacing the drive system's belts and pulleys with a direct drive provides system improvements including increased efficiency without incurring more cost and, at the very least, having a cost-neutral position at the system level. Regional efficiency directives, such as the need to achieve 13 SEER in AC systems in the U.S., are accelerating the trend toward brushless motors. That means that brushless should start to overtake the ac induction in certain applications, says Dan Jones, president, Incremotion Associates and well-known motor control expert.
Alternate Technologies
The paradigm shift in many traditional electromechanical areas comes from implementing electronics technology. The case of solid-state relays is a well-known example. Power semiconductors handle the switching of amps and high voltage adding analog and digital circuitry provides a smart power switch or solid-state relay. However, electromechanical relays continue to grow and solve problems and meet the system cost criteria. In automobiles for example, an average North American vehicle still has from 20 to 30 relays.
Other electromechanical areas being challenged by electronics technology include cooling and protection. Thermoelectric techniques to address spot cooling can replace fans in some applications. In more complex situations, larger thermoelectric ac systems such as TECA Corp.'s FHP-1501 series air conditioners provide a NEMA-12 rated enclosure for indoor use for protection against dust, falling dirt and dripping non-corrosive liquids. In addition, the unit does not use a compressor, fluorocarbons or filters.
Protection traditionally handled by circuit breakers is also under attack. Circuit breaker disconnects can be prevented by using surge suppression and overvoltage/overcurrent protection built into the electronics circuitry itself. The use of these protection techniques is increasing since the hardware is expensive and avoiding downtime is critical to keep cost down. In this case, the circuit breaker is not being displaced but several options are increasing.
Cost Implications
Cost has many facets for electromechanical components. From the materials side, copper is up 31 percent and iron is up anywhere from 10 to 15 percent last year according to Jones. At the same time, the cost of high-performance magnets has decreased. Since the copper and iron costs have a similar impact on both induction and permanent magnet motors, the lower cost magnetics seem to be shifting motor design in the most efficiency sensitive areas.
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 TECA Corp.'s FHP-1501 series AC unit uses thermoelectric cooling. |
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