Temperature measurement technology for electric motors – Your solution for vehicle testing and test bench measurements

Whether on the test bench or in driving operation, the high power density of modern electric drives for hybrid and purely electrically powered vehicles places the highest demands on the temperature measurement technology in the rotor. It serves to precisely and reliably record the temperature profile of the motor in all operating situations. Based on this data, developers and designers can ensure that critical temperatures are not reached in any driving conditions.

Sophisticated, trouble-free and reliable temperature telemetry for electrical machines

When using temperature measurement technology in the “heart” of the electric motor, factors come together that place the highest demands on measurement and transmission technology. High temperatures, high speeds, strong electromagnetic influences and, last but not least, tight installation space are all part of the picture. This is where the strengths of MANNER sensor telemetry come into their own.  Temperature resistance up to 200°C, high electromagnetic robustness, oil resistance and high freedom of design in combination with compact construction and highest speeds up to 30,000 rpm which were only known from the aviation industry before.

Figure 2: Rotor and stator of a 6-channel electric motor temperature telemetry system

From start-up to acceleration and uphill driving, temperature control is one of the decisive factors for operational safety in subsequent series production. This is because the permanent magnetisation of modern electric drives based on rare-earth magnets must not be endangered at any time by exceeding the Curie point.

The acquisition unit and telemetry modules from MANNER measure reliably and precisely to 1°C under the toughest operating conditions. If desired, even digitally compensated to <0.2 °C deviation from the measured value.

Comfort and robustness – The sensor and data transmission

When using MANNER technologies for temperature measurements in electric drives, any thermocouples (type J, K etc.) or alternatively Pt100 temperature sensors can be used. As a rule, only 0.5 mm thick, flexible thermocouples are used. The necessary hole diameter for the wiring has a negligible effect on the drive process. The wiring up to the desired measuring point inside the drive is carried out by MANNER. This guarantees high reliability.

The rotor telemetry is robust against EMC and depending on the customer’s requirements, is designed for speeds of up to 30,000 rpm. The flexible and compact design of the telemetry is also worthy of special mention.

The smaller the installation space available for the application, the more important it is to design the telemetry housing to fit precisely and save space. MANNER’s miniature telemetry components, technologies and systems allow the modular integration of telemetry in rotors of any geometry. To ensure that the housing can be optimally adapted to every rotor and every installation situation, MANNER designs each housing specifically for the application if required.

The measurement data is digitised in the rotor telemetry and transferred to the miniaturised stator unit using the proven MANNER telemetry data transfer method. As the market leader, we have designed, produced and tested more than 500 measuring telemetries for temperature detection in the electric motor of well-known automobile manufacturers and suppliers according to customer-specific requirements.

The system solves your measuring task, whether installed in-situ or directly at the winding head of the electric motor.

 

Reliable – Data acquisition and evaluation

The measuring signals of the thermocouple are recorded without contact and transmitted to the stationary side. These measurement data can be transmitted classically as an analogue signal with 0 … ±10 V; 4…20mA or also as a digital signal via the CAN interface, EtherCAT or Ethernet to the data acquisition system. All MANNER telemetry modules used are temperature-resistant up to 200°C.

If desired, the measurement signal can be output directly as a temperature value and thus the comfortable and seamless interpretation of the measurement run can be realised.

 

Experienced engineering team

Miniaturised, modular components open up a high degree of design freedom for the MANNER engineering team with regard to the form factor of the sensor signal amplifier for the integration of the amplifier housing at its installation location in the rotor. Typical for the shape of the housing are ring- or bullet-shaped designs.

Figure 3: Applied temperature rotor telemetry 6-channel with integrated rotor antenna in-situ at the electric motor

 

MANNER’s unique combination of benefits

Maximum robustness for high temperatures and speeds. Optimal electromagnetic immunity and professional engineering. This unique combination of advantages gives MANNER technologies a leading industrial maturity. Maintenance-free and with unlimited service life, they reliably provide developers and designers with precise measured values.

For over 30 years MANNER Sensor Telemetry has been dealing with the contactless transmission of sensor signal data from suspension units and shafts. Our basic principle is: “We accept challenges that others reject. Finding solutions to seemingly intractable problems – that is what we do best!”