Product Description:

The T840T-012 is a DC servo motor built by Sanyo Denki for the T SANMOTION Servo Motors series. As a feedback-controlled drive element, the unit converts armature current into precise rotary motion for positioning or regulating machine axes in industrial automation cells, pick-and-place heads, and light-duty actuators. Its electrical design pairs with matched amplifiers so that commanded current generates proportional torque, allowing closed-loop velocity and position control without mechanical gear reduction.

During continuous operation, the motor can maintain a stall torque of 1.70 N·m, while its nominal load point has a rated torque of 1.57 N·m and a mechanical output of 400 W. That load point corresponds to a shaft speed of 2500 rpm and is reached when 5.8 A flows through the 85 V armature circuit. A stall current of 6.0 A sits only slightly above the rated value, indicating a limited difference between the two current levels. The torque constant is 0.314 N·m/A, so every ampere of commanded current produces roughly one-third of a newton-meter of torque, simplifying drive gain calculations. The winding has an inductance of 1.9 mH, which balances current-ripple attenuation with dynamic response. The in-line tachometer provides velocity feedback to loads with an impedance of 10 kΩ.

For short bursts, the shaft can reach a top speed of 4000 rpm, and the magnetic circuit can deliver up to 12.0 N·m when 40 A of armature current is permitted. This peak output provides rapid acceleration for indexing moves that remain within the motor’s allowable short-term duty. The rotor has a polar moment of 0.50 × 10⁻³ kg·m², helping limit overshoot while storing enough kinetic energy for smooth motion. The armature winding has a resistance of 0.95 Ω, so peak duty cycles must account for I²R heating when current exceeds the continuous limit. The assembly weighs 3.4 kg, which eases mounting on small frames while providing sufficient mass for vibration damping.