To date, in Italy, most lift traction machines upgrade is conservative and consists in replacing the existing gearbox, typically with a 2-speed motor (AC2), with a new generation gearbox, sometimes with 2-speed motor (AC2) but more often with VVVF motor and inverter. Replacing a gearbox machine with AC2 motor with a gearbox machine with VVVF motor with inverter with the same suspension system (1: 1), allows the use of a smaller machine with a lower power motor, thus limiting not only the overall dimensions but also the size of the inverter and above all the power of the facility. In most upgrades, given the trips and speed of the facility, good comfort in the cabin can be achieved even in open-loop configurations, therefore without the use of the encoder, thus limiting the cost of the new solution, which is still a “dated” and not “green” solution due to the presence of oil. The current trend is replacing the gearbox with a gearless device, mainly because the latter is characterized by: • high efficiency of the permanent magnet motor which translates into reduced consumption; • limited size that allows transport, installation and use in any system; • maximum comfort in the cabin resulting from a more precise regulation of the closed loop gearless machine that meets the facility’s specific needs; • floor re-levelling in any load condition; • lowest level of noise and vibrations over time (absence of gears / gears subject to wear); • absence of oil and lubricants; • reduced maintenance; • equipped with a certified brake both against excess speed of the ascending car and against uncontrolled movements of the car with doors (UCM), which means increasing the original safety level; • no cabin speed limit; • no trip limit. The gearless machine consists of a permanent magnet motor, called torque motor as it is able to provide high output torque to the shaft at low speeds, exactly like the worm gear reducer of the gearbox machines, but without having internal gears which are subject to wear as well as being unsuitable for high speeds due to vibrations and noise. The gearless machine is “essential”, consisting of fewer components compared to the gearbox machine (only permanent magnet motor, traction pulley, brake and encoder) it reduces the chances of failure and wear. In particular, the brake assembled on the gearless machines is certified both against the ascending car’s excess speed and unwanted movements of the car with part doors (UCM), therefore it constitutes a safety component according to EN 81- 20: 2020 as it acts directly on the same shaft as the clutch pulley (which is statically supported in 2 points). This means that the facility on which the gearless machine is installed is already equipped with this “free of charge” safety component which therefore allows an increase in the safety of the facility itself, unlike the gearbox machines whose safety brake on the output shaft is a relevant cost. Gearless devices guarantee the typical permanent magnet motors high efficiency, and increasingly use an inverter with a regenerative module, which functions as a generator during operation, sending the energy to the network which can then be used to power the building’s electrical loads, leading to a considerable increase in the energy efficiency of the entire lift. To obtain the highest economic benefit from the gearless machine, the suspension system should be changed from 1: 1 to 2: 1 as this allows for a smaller machine, significantly limiting the costs of replacing the original winch. The gearless machine with its extremely compact design, allows easy transport and positioning in the engine room without the need for partial disassembly, as is the case with gearbox machines. It is also possible to position the gearless machine on existing frames with simple interfaces / adapters. In the case of replacement of the gearbox machine with external support of the traction pulley (very frequent configuration in “dated” systems) with a new generation gearbox machine, it is advisable to verify, through the system data, the best possible configuration to avoid unnecessary expenses. Various dated gearbox machines had an external slow shaft support, also called third support, whose correct installation was by no means trivial. Aligning 3 supports implies extremely accurate implementation which, in the Replacing the gearbox machine with a gearless machine has numerous benefits Upgradingwinches: the state of the art and current trends 47
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