Counterweight Mass
Calculate an elevator's counterweight mass, M_cw = M_car + factor × Q_max, from the car mass, the balancing factor (typically 0.40 to 0.50) and the maximum load Q_max (kg). The result, in kg, is the mass that balances the car plus a fraction of the payload, so the motor works with the smallest average imbalance. A factor of 0.45 (45%) is common: it fully balances the car and 45% of the rated load, minimizing motor work both with a full and an empty car. Enter the car mass, the balancing factor and the maximum load.
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Massa do contrapeso
O contrapeso é o que torna o elevador de tração eficiente: em vez de o motor levantar todo o peso da cabine e da carga, ele só vence o desbalanceamento entre os dois lados da polia. A massa do contrapeso é M_cp = M_cabine + fator × Q_max, onde o fator de balanceamento (tipicamente 0,40 a 0,50) define que fração da carga máxima ele compensa. O valor clássico de 0,45 (45%) tem uma lógica elegante: o contrapeso equilibra totalmente a cabine mais 45% da carga nominal. Assim, o desbalanceamento (e o trabalho do motor) é o mesmo quando a cabine está vazia (contrapeso mais pesado, puxa para cima) e quando está com ~90% de carga (cabine mais pesada) — distribuindo o esforço de forma simétrica em torno da condição de equilíbrio (cabine a 45%). Isso minimiza a potência de pico, o consumo e o desgaste, já que os elevadores raramente viajam totalmente cheios. Informe a massa da cabine, o fator de balanceamento e a carga máxima.
Related Tools
Hoist Rope Tension
Calculate the resultant force in an elevator's hoist rope, F = (Q + M_car − M_counterweight)·g, from the payload Q, the car mass and the counterweight mass (kg). The result, in newtons, is the unbalanced effort the steel ropes must transmit, already net of the counterweight's balancing effect. It is the basis for sizing the ropes (number, diameter and safety factor, typically ≥ 12 in elevator codes) and the traction sheave. When the load is such that car + load ≈ counterweight, the force tends to zero (balanced system). Enter the load, the car mass and the counterweight mass.
Elevator Motor Power
Calculate the motor power of an elevator, P = m·g·v ÷ η, from the payload m (kg), gravity g (9.81 m/s²), nominal speed v (m/s) and the system efficiency η (motor, gearbox, sheaves). The result, in watts, is the mechanical power needed to hoist the load at nominal speed. In practice, the counterweight (balancing the car plus ~45% of the load) reduces the effective power, and regenerative braking on descent can return some to the system. It is the base calculation for sizing the traction machine. Enter the load, the speed and the efficiency.
Belt Transmitted Power
Calculate the power transmitted by a belt, P = (T₁ − T₂)·v, from the tight-side tension T₁ (N), the slack-side tension T₂ (N) and the belt velocity v (m/s). In a belt drive, the driving pulley drags the belt by friction, creating a DIFFERENCE in tension between the two sides: the side that 'pulls' (tight side, T₁) is more tensioned than the side that 'follows' (slack side, T₂). This difference (T₁ − T₂), the effective tension or tangential force, is the net force that actually transmits motion; times the belt velocity, it gives the transmitted POWER. The larger the tension difference the belt can sustain without slipping (depending on friction, wrap angle and, in V-belts, the wedging effect of the pulley walls), the greater the transmissible power. Power also grows with belt velocity — so high-power drives use large pulleys and fast belts (up to a limit, since centrifugal tension reduces available friction at very high speeds). This is central in belt-drive design, present in almost every rotating machine: motors, fans, pumps, compressors, machine tools and vehicles. Enter the tight- and slack-side tensions and the belt velocity.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.