Complete solution of ETEL TMB+torque motor selection parameters

Selection and parameter interpretation of ETEL TMB+series direct drive torque motor

In the application fields of high-end CNC machine tools, semiconductor manufacturing, robot joints, and precision turntables, direct drive torque motors are gradually replacing traditional "servo motor+decelerator" solutions due to their advantages of zero backlash, high rigidity, high dynamic response, and low maintenance costs. The TMB+series of ETEL (a Swiss company under the Heidelberg Group) is a well-known frameless torque motor product line in the industry, providing a complete selection spectrum from diameters of 0140mm to 1221mm and peak torque from tens of Newton meters to tens of thousands of Newton meters. This article is based on the official technical data manual, systematically interpreting the model system, core performance parameters, thermal management points, and selection methodology of the TMB+series, to help motion control engineers quickly locate suitable motor specifications.

Series Overview and Model Naming Rules

The TMB+series covers a variety of machine base sizes, including 0140, 0175, 0210, 0290, 0291, 0360, 0450, 0530, 0760, 0990, 1221, etc. (numbers usually represent stator outer diameter or series code). Each type of machine base provides multiple voltage/current/torque combinations based on winding design (such as SA, SB, TA, TB, UA, UB, UD, VA, VB, WD, WH, etc.) to meet different bus voltages (standard 600VDC) and application load curves. For example:

TMB+0140-030: A motor with an outer diameter of approximately 140mm, where 030 may represent a certain length or torque level.

TMB+0175-050: outer diameter of approximately 175mm, rated torque of approximately 50Nm level.

TMB+0210-150: The outer diameter is about 210mm, and the peak torque can reach about 200Nm.

TMB+0360-200: outer diameter of approximately 360mm, peak torque exceeding 2900Nm.

TMB+0450-200: Peak torque of over 4800Nm.

TMB+0530-150: Peak torque exceeding 5000Nm.

TMB+0760-150: Peak torque exceeds 11000Nm.

TMB+0990-200: Peak torque exceeds 27000 Nm.

TMB+1221-150: Maximum model with peak torque exceeding 30000 Nm.

Multiple windings are usually provided under each model (such as winding codes: SA, SB, RA, RB, TA, TB, UA, UB, UD, VA, VB, WD, WH, UJ, WT, etc.), and different windings correspond to different torque constants (Kt), back electromotive force constants (Ku), resistance, and inductance, thereby affecting the torque output capability and copper loss at different speeds.

Interpretation of Core Performance Parameters

The technical data sheet is organized into three main sections: Motor Performance, Motor Setting, and Motor Environment.

2.1 Motor performance parameters (dynamic capability)

Peak torque (Tp): The maximum torque that can be output in a short period of time (usually 5% duty cycle), used for acceleration, deceleration, and overcoming instantaneous loads. For example, the SA winding Tp of TMB+0140-030 is 39.6Nm, while the WD winding Tp of TMB+0990-200 exceeds 27000 Nm.

Intermittent torque (Ti): The torque that can be continuously output at a 40% duty cycle, suitable for periodic loads.

Continuous torque (Tc): The torque that can be continuously output under 100% duty cycle and water-cooled conditions (thermal balance). This is the ability boundary of the motor for long-term operation.

Static torque (Ts): The torque that can be continuously output at zero or low speed (without speed limitation, mainly subject to thermal limitation).

Corresponding currents (Ip, Ii, Ic, Is): peak, intermittent, continuous, and static currents (effective value, Arms), respectively. These current values directly determine the selection capacity of the driver.

Maximum speed (nm, nm, FW): The highest speed under conditions of no weak magnetic field and weak magnetic field. Note that weak magnetism can reduce torque capacity, but it can expand the range of constant power speed regulation.

Peak/Intermittent Duration (τ on, p, τ on, i): The maximum time allowed to continuously apply peak/intermittent torque, typically in seconds, used for designing acceleration and deceleration times.

Power loss (Pp, Pi, Pc): Copper loss (winding heating) corresponding to current, is an important input for thermal management.

2.2 Motor Setting Parameters (Electrical/Mechanical Characteristics)

Torque constant Kt (Nm/Arms): The torque generated per unit current is the most critical parameter for selecting windings. High Kt means greater torque at the same current, but also higher back electromotive force, limiting high-speed performance.

Back electromotive force constant Ku (Vrms/(rad/s)): The voltage generated per unit speed directly affects the driver voltage margin and weak magnetic control strategy.

Motor constant Km (Nm/√ W): an indicator for measuring the electromagnetic efficiency of a motor, Km = Kt / √R， The larger the value, the stronger the torque output capability under the same copper loss.

Phase resistance R20 (Ω): The DC resistance at 20 ℃ affects copper loss (I ² R) and increases with temperature (temperature coefficient of copper resistance is about 0.4%/K).

Phase inductance Ld/Lq (mH): Direct and quadrature axis inductance, affecting current rise rate and high-speed performance.