Page 232 - Demo

V012024 • © 2024 Portescap. Specifications subject to change without notice.Since the gearhead has a diameter of 16 mm we will be looking at 16 mm Brushless DC motors. Based on the load torque (τm) the motor will be required to turn, we select the 16ECP36 8B (the 8B refers to the option for Hall Effect Sensors).The 16ECP36 8B is available in 4 different windings. Windings offer same overall performance (maximum torque, merit factor, etc...) but help using different voltage and current configurations. Since the desired motor speed is 7,260 rpm we will investigate the 16ECP36 8 B 245 with a no load speed of 12,420 rpm under a 24V supply voltage. The torque constant is 17.6 mNm/A and the line to line resistance is 21.1 Ω.Calculating for the motor current we find: I = τ / k + I0 = 1.91 mNm / (17.6 mNm/A) + 35 mA = 0.14 AThere are no issues with the current because the system is able to supply 2 amps and the maximum recommended continuous current is 0.4 Amps. The voltage required to run the motor at 7,260 rpm is determined by the following formula: U = R × I + k × ω ω = 2π/60 × n = 2π/60 rad/rpm-s × 7,260 rpm= 760.3 rad/s U = 21.1 Ω × 0.14 A + (17.6 × 10−3 Nm/A) × 760.3 rad/s = 16.33 VdcThe problem is now solved. The voltage required is less than the available voltage, therefore the motor 16ECP36 8B 245 with the planetary gearhead R16 0 121 can achieve the desired working point. If the application were very noise sensitive, a lower ratio would help reducing the gearbox input speed which is the main contributor of noise.Torque [oz-in]Speed (rpm)Torque [mNm]Max. continuous operation at 25°C5W10W15W20W30W0 0.2 0.4 0.6 0.8 1 1.2010,00020,00030,00040,00050,00060,00070,0000 1 2 3 4 5 6 7 8ContinuousShort time232Engineer’s Appendix