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WEG IE3 compliant motor control and protection
WEG motors are IE3 compliant.
WEG control and protection components.
Reliable protection for an electric motor is essential in any application.
Reliable protection for an electric motor is essential in any application and with the increased move towards the use of IE3 motors by the South African farming community it has become increasingly important that the most appropriate starting method be selected to ensure optimum performance. IE 3 motors have greater inductances when compared to standard motors, and the copper losses are smaller, resulting in starting currents that are higher than conventional or IE1 and IE 2 motors. As a consequence of this, it is essential that the motor switching and protection components are engineered to meet the demands of the IE3 motor. Generally, the most basic starting method for an electric motor would be a direct online starter or star delta starter, however older generation switchgear has not been engineered for IE3 motor compatibility. The
increase in the starting currents may generate nuisance tripping on start-up conditions. Not only is this undesirable, it can also have a severe knock on effect in terms of operational productivity and efficiencies. A good example of this would be where a pumping operation is not activated timeously, affecting the irrigation of the crops, and if not solved could have an adverse effect on the actual harvest. WEG IE3 compliant low voltage switchgear has been engineered to offer absolute reliability while accommodating higher inrush and starting currents. Users can be confident that when using WEG IE3 compliant switchgear, their drive system will provide the highest levels of energy efficiency over a long service life. This will, in turn, translate into a reduction in the total cost of ownership (TCO) while complying with current environmental regulations.
WEG Motor Protective Circuit Breakers Typically, motor protective circuit breakers are affected most by the high starting current and inrushes of premium efficiency motors and this is because of sensitivities to transients and instantaneous values of current. WEG circuit breakers were evaluated specifically in terms of this and the multiple of short circuit release was changed from 12 to 13 times the rms value of the rated current. Following this modification, extensive testing was conducted to verify that with these modifications the whole range of WEG circuit breakers is IE3 compliant. WEG Contactors Improvements were made to WEG contactors and the entire range is IE3 compliant. Inrush is a transient phenomenon that only occurs during the first half-cycle of the current, and this was dealt with by reducing the contact bouncing levels during start up. This important and effective improvement was achieved by reducing the kinetic energy of the contacts through improving several components making the entire movable assembly lighter. Copper alloys with special hardness have also been used and the design of cores and coils optimised. The application of sound engineering principles has ensured that there has not been a mechanical or electrical lifespan reduction, or an increase in the contactor’s coil consumption. WEG Overload Relays Overload relays are designed to protect motors thermally against overload conditions and, unlike motor protective circuit breakers, are not sensitive to instantaneous currents. WEG solid-state and thermal overload relays conform to IE3 motor application Significantly, as a leading manufacturer of premium (IE3) and super-premium (IE4) electric motors, WEG has developed extensive expertise in IE3 equipment conformity and all WEG’s current switchgear and protection devices can be used without restriction to ensure the reliable operation of IE3 motors. Zest WEG Group’s technical team is able to assist customers in the appropriate selection of IE3 compliant control and protection components to optimise the efficiency of motor installations.
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