# Uncertainty in current values of Power HD digital servo motor

In a project, we want to lift the load of 5 kg on the ground to half a meter. For this purpose, we use a 360-degree rotating PowerHD digital servo motor with a stall torque of 20 kg / cm.

Motor characteristics according to datasheet;

Stall Torque for 6.6v: 20 kg/cm

Stall Current for 6.6v: 2710 mA

We just wrote a simple servo motor control code on the Arduino Nano for testing the power of the motor. After connecting a shaft to the motor, we added a load of about 2 kg to the shaft and operated the system with a DC power supply. While the servo motor lifting a load of 2 kg with a rope up to a half meter, sometimes it stopped and sometimes pulled the load up too fast. In this case, the maximum current that the servo motor draws from the system is 1 amps (when the voltage is between 6.6 and 7 volts). To increase the load connected to the system and force the motor, we hold the shaft by hands. But even in this case, the current that the motor draws is 1.2 amps (the voltage we give to the system is between 6.6 and 7 volts).

According to characteristics of the servo motor, the servo motor is drawn 2.5 amperes current at 20 kg torque. We did not reach the current value of 2.5 amperes, although we forced the engine too much. I think we can lift the load if we reach 2.5 amps, but even we can not reach up to 1.3 amps and above values. What are the details we need to review to solve this? Can the cable thickness prevent high current? Or should we increase the frequency of the servomotor?

Thank you

• RC servo motors torque and current ratings provided by manufacturers are unreliable, erratic, and subject to massaging by the marketing department. Don't put too much weight into them. They also aren't meant to run at their stall torque. Think of the stall torques provided as just a relative metric to compare one servo to another, not an absolute value. Measure it with your set up and that's what it is given your test setup. Don't try and compare it against the manufacturer because you don't know their set up. – Toor Mar 6 at 21:28