Unattended elevator systems, especially those transporting people, require high reliability and minimal maintenance throughout their lifespan.
RONK ELECTRICAL INDUSTRIES pioneered single-to-three phase conversion with the introduction of the ADD-A-PHASE® converter in 1952. This converter has proven so reliable that it is still widely specified today to power a wide range of three-phase loads from single phase utility power. The TYPE HE-AA (automatic adjust) ADD-A-PHASE extends applications for static autotransformer–capacitor converters to equipment with loads varying more than 50%, such as hydraulic elevators. A load-sensing circuit allows the run capacitors to be automatically switched in and out with changes in the elevator motor’s load requirements. This ensures the TYPE HE-AA ADD-A-PHASE converter maintains reliable current balance under variable load conditions. Traditionally, phase conversion for elevator motors has been handled by rotary phase converters, which most converter manufacturers produce. The TYPE HE-AA ADD-A-PHASE allows hydraulic elevator manufacturers to leverage the advantages of the autotransformer-capacitor design over rotary phase converters.
Rotary phase converters can be problematic in ensuring the reliability required for elevator systems. They often use automatic controls such as timers and relays to initiate the elevator motor only when needed, increasing the electromechanical content and compromising system reliability. In contrast, the TYPE HE-AA ADD-A-PHASE is fully automatic with only one electromechanical component—a switching relay—resulting in longer life and greater system reliability.
Rotary phase converters, whether with or without automatic controls, are significantly less energy efficient than the TYPE HE-AA ADD-A-PHASE converter. Rotary converters maintain their rotating elements (rotors) during no-load conditions, resulting in much higher idle losses. Furthermore, rotary converters do not usually balance phase currents, leading to inefficiencies in load motors. The ADD-A-PHASE type converter is 97% efficient, with no-load losses limited to very small excitation losses in the autotransformer. For example, a 15HP TYPE HE-AA ADD-A-PHASE would only produce about 60 watts of no-load losses, maintaining excellent current balance and efficient motor operation.
From a resting state, the rotor of a rotary converter must accelerate to its synchronous speed before the elevator motor can be initiated, typically taking 3-10 seconds. The TYPE HE-AA ADD-A-PHASE converter, being constantly energized, provides an immediate response for the elevator motor without causing system sag.
Electromechanical systems such as rotary phase converters generate mechanical noise from sources including rotor windings, capacitor shrouds, frame movement, and magnetizing current whine. Rotary converter noise levels increase as bearings wear. The TYPE HE-AA ADD-A-PHASE converter, with only one moving part—a switching relay—produces very little noise. This low noise level is crucial in buildings where room and elevator shaft cavities amplify certain frequencies. Quieter than rotary converters, the TYPE HE-AA ADD-A-PHASE autotransformer-capacitor converter is ideal for elevator systems and noise abatement needs. Unlike newer electronic phase converters and drives that generate harmonics, the TYPE HE-AA ADD-A-PHASE does not.
The TYPE HE-AA ADD-A-PHASE converter is guaranteed to develop the full load rating of the elevator drive motor plus normal overload. It outperforms other converter models in terms of performance, noise abatement, and lack of harmonic generation, making it the preferred choice for powering three-phase hydraulic elevators from single phase utility service.
The RONK TYPE HE-AA ADD-A-PHASE is an excellent choice for hydraulic elevators where only single phase power is available. This product is 97% energy efficient, has low inrush on single phase lines (required by most utility providers), generates no harmonics, has low idle losses, a very low audible noise signature, a near unity power factor, and is over 90% recyclable.
Contact our Sales team for more information on the RONK line of TYPE HE-AA ADD-A-PHASE®: 1-800-221-7665
