Conveyor speed
Crop throughput
Motor speed
Drive speed
Torque
Drive force
Incline & payload
Duty / force factor
IE3 electrical estimate
Overload setting ≈ the running current for the chosen connection. Typical IE3 values (50 Hz, 4-pole) at the supply voltage — verify against the motor nameplate before sizing protection.
Recommendation
Nearest standard gearbox ratio, then the next standard IEC motor size for each connection. Star runs the motor at rated output; delta gives 3× torque, so a motor a third the size meets the same target — at ~3× the line current. Amps are IE3 guesstimates at the supply voltage.
Speeds
Implied crop load
Torque & power required
IE3 electrical estimate
Overload setting ≈ the running current for the chosen connection. Typical IE3 efficiency and power factor (50 Hz, 4-pole) — verify against the motor nameplate before sizing protection.
Check with standard picks
Recomputed with the standard gearbox ratio and standard motor sizes, keeping the same crop loading (kg/m). Trim the VFD standard frequency to close the speed error.
Constants
1 N = 0.101971621297793 kgf (standard gravity g = 9.80665 m/s²) delta torque multiplier = 3 star = rated output; delta = 3× torque at ~3× line current
The 3× star/delta factor follows the original workbook: the motor runs star at rated output and delta connection triples torque, current, and power.
Motor & drive speed
N_motor = (f × 120 / p) × (1 - s/100) [rpm]
evaluated at f_min, f_std, f_max
N_drive = N_motor / i [rpm]
Synchronous speed from frequency and poles, derated by slip.
Motor torque
ω = 2π × N_motor,std / 60 [rad/s] T_motor = P × 1000 / ω [Nm]
Rated torque at the standard-frequency operating point.
Drive torque & force
T_star = T_motor × i × ηd [Nm] T_delta = 3 × T_star F_star = T_star / (r / 1000) [N] F_delta = 3 × F_star F[kgf] = F[N] × 0.101972
Conveyor geometry & speed
C = 2 × π × r / 1000 [m] v = C × N_drive,std [m/min] cycles/min = (v / C) × 2
Crop load & throughput
m_crop = h × L × w × ρ [kg] loading = h × w × ρ [kg/m] feed = loading × v [kg/min] throughput = feed × 60 / 1000 [t/h]
Incline force & payload
m_total = m_shaft + m_belt + m_crop F_req = m_total × (μ·cosθ + sinθ) [kgf] F_req[N] = F_req / 0.101972 payload_star = F_star[kgf] - F_req payload_delta = F_delta[kgf] - F_req
Friction plus the gravity component along the belt. Negative θ (downhill) reduces or reverses the required force.
Duty / force factor
duty = (F[kgf] - F_req) / m_crop
Force margin over the incline load, per kg of crop. ≥ 1.0: the drive can move the full crop load with margin. 0–1: marginal. < 0: cannot overcome friction/incline at all.
Sizing — gear ratio
N_drive,req = v_target / C [rpm] i_exact = N_motor,std / N_drive,req i_std = nearest of standard series 5, 7.5, 10, 12.5, 15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 100
Sizing — motor power
loading = (tph × 1000 / 60) / v_target [kg/m] m_crop = loading × L F_needed = F_req + D × m_crop [kgf] T_drive = F_needed[N] × r / 1000 [Nm] T_motor = T_drive / (i_exact × ηd) P_star = T_motor × ω / 1000 [kW] P_delta = P_star / 3 next standard IEC size up: 0.12, 0.18, 0.25, 0.37, 0.55, 0.75, 1.1, 1.5, 2.2, 3, 4, 5.5, 7.5, 11, 15, 18.5, 22 kW
The target throughput at the target speed implies the crop loading; power is what achieves the target duty factor D. Delta needs a third of the rating for the same force.
Sizing — check with standard picks
N_drive = N_motor,std / i_std
v_actual = C × N_drive
tph_actual = loading × v_actual × 60/1000
speed error = (v_actual - v_target)
/ v_target × 100%
duty achieved: forward equations re-run
with i_std and the standard kW, keeping
the same loading [kg/m]
IE3 electrical estimate
I_FL = P × 1000 / (√3 × V × η × pf) [A] star running ≈ I_FL delta running ≈ 3 × I_FL overload setting ≈ running current for the chosen connection
η from the IE3 minimum-efficiency table (IEC 60034-30-1, 50 Hz 4-pole) with typical power factors, log-interpolated between sizes. Guesstimates — verify against the nameplate.
IE3 table used (50 Hz, 4-pole)
kW η pf kW η pf
0.12 64.8% 0.65 2.2 86.7% 0.80
0.18 69.9% 0.66 3 87.7% 0.81
0.25 73.5% 0.68 4 88.6% 0.82
0.37 77.3% 0.70 5.5 89.6% 0.83
0.55 80.8% 0.72 7.5 90.4% 0.84
0.75 82.5% 0.74 11 91.4% 0.85
1.1 84.1% 0.76 15 92.1% 0.85
1.5 85.3% 0.78 18.5 92.6% 0.86
22 93.0% 0.86
Input limits
frequency 5 – 400 Hz, min ≤ std ≤ max slip 0 ≤ s < 100 % drive efficiency 0 < ηd ≤ 1 inclination -89° to +89° friction μ ≥ 0 all dimensions, masses, density, power, voltage, ratio, speed > 0
Same validation rules as the original macro, applied per field as you type.