maxon Product Range 2021/22

8

Rear

7

10

4

9

3

Front

2

5

1

6

9

Hall sensor circuit The open collector output of Hall sensors does not normally have its own pull-up resistance, as this is integral in maxon controllers. Any excep- tions are specifically mentioned in the relevant motor data sheets.

Winding arrangement The maxon rhombic winding is divided into three partial windings, each shifted by 120°. The partial windings can be connected in two different manners - “Y” or “ D ”. This changes the speed and torque inversely proportional by the factor 3 . However, the winding arrangement does not play a decisive role in the selection of the motor. It is important that the motor-specific parameters (speed and torque constants) are in line with requirements.

Sinusoidal commutation The high resolution signals from the encoder or resolver are used for generating sine-shape motor currents in the electronics. The currents through the three motor windings are related to the rotor position and are shifted at each phase by 120° (sinusoidal commutation). This results in the very smooth, precise running of the motor and, in a very precise, high quality control. Properties of sinusoidal commutation − More expensive electronics − Field-oriented control (FOC) − No torque ripple − Very smooth running, even at very low speeds − Approx. 5%more continuous torque compared to block commutation − Highly dynamic servo drives − Positioning tasks

Wiring diagram for Hall sensors Hall sensor supplyvoltage

R Pull-up

Control circuit

« ∆ »-circuit

«Y»-circuit

Hall sensor output

W 1

W 1

U 1-2

U 3-1

U 1-2

U 3-1

GND

W 2

W 2

W 3

W 3

The power consumption of a Hall sensor is typically 4 mA (for output of Hall sensor = “HI”).

U 2-3

U 2-3

Bearings and service life The long service life of the brushless design can only be properly exploited by using pre- loaded ball bearings. − Bearings designed for tens of thousands of hours − Service life is affected by maximum speed, residual unbalance and bearing load

Currents in sine and block commutation

Sinusoidal phase currents

Block-shaped phase currents

Legend 1 Star point 2 Time delay 30°e 3 Zero crossing of EMF

300° 0°

60° 120° 180° 240° 300°

For further explanations, please see page 178 or “The selection of high-precision microdrives” by Dr. Urs Kafader.

Turning angle

57

Technology – short and to the point

Juli 2021 edition / subject to change

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