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Wireless temperature measurement system for electric motors rotor

IP.com Disclosure Number: IPCOM000241304D
Publication Date: 2015-Apr-15

Publishing Venue

The IP.com Prior Art Database

Related People

Pietro Savio Termini: AUTHOR [+4]

Abstract

The invention is a wireless temperature measurement system for rotating electrical machines and consists of three main parts: - Thermocouples - Signal conditioning amplifiers (one for each thermocouple). - Xbee modules (transmitter and receiver), that create a wireless connection and enable the communication with a remote PC. The thermocouples are fixed into the rotor of the machine and connected to the conditioning amplifiers, whose output pins are connected to a wireless Xbee transmitter. The number of thermocouples and amplifiers influence the dimensions of the on-board device.

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This is the abbreviated version, containing approximately 51% of the total text.

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Wireless temperature measurement system for electric motors rotor

Goal:

better understanding of the thermal response of an electrical machine

capability to monitor and analyze the evolution of the temperature of rotating parts during thermal transients

Termosensitive materials are often used to determine the highest value of temperature reached by the rotating parts of an electric motor during test sessions.

However, some applications require a more accurate thermal analysis.

This aspect is critical, expecially in small size motors.

A WIRELESS TEMPERATURE MEASUREMENT SYSTEM FOR ROTATING ELECTRICAL MACHINES

lT-1305901

© ABB Group April 14, 2015


Page 02 of 15

lT-1305901

The measurement system consists of three main parts:
Thermocouples

Signal conditioning amplifiers (one for each thermocouple).

Two Xbee modules (transmitter and receiver), that create a wireless connection and enable the communication with a remote PC.

The thermocouples are fixed into the rotor of the machine and connected to the conditioning amplifiers, whose output pins are connected to the Xbee transmitter.

The conditioning signal circuits and the Xbee transmitter module are fixed to the rotor of the motor:

The transmitter rotates with the rotor.

The trasmission circuitry is powered by batteries in series.

A WIRELESS TEMPERATURE MEASUREMENT SYSTEM FOR ROTATING ELECTRICAL MACHINES

© ABB Group April 14, 2015


Page 03 of 15

lT-1305901

The receiver is connected to the PC through a commercial USB cable

A dedicated software elaborates the received bytes and convert them into voltage and temperature values.

Data are plotted in graphs and recorded into "Data Log" files.

A WIRELESS TEMPERATURE MEASUREMENT SYSTEM FOR ROTATING ELECTRICAL MACHINES

© ABB Group April 14, 2015


Page 04 of 15

lT-1305901

Thermocouples used for the prototype:
Type J (Iron/Constantan)

Temperature range: -40°C +750°C

Detect the temperature in four different points of the rotor

Nominal sensitivity: 51 µV/°C

A WIRELESS TEMPERATURE MEASUREMENT SYSTEM FOR ROTATING ELECTRICAL MACHINES

© ABB Group April 14, 2015


Page 05 of 15

lT-1305901

Signal conditioning circuit:

Integrated amplifier

Output pin connected to ADC pin of the Xbee transmitter

Chosen solution:

Analog Devices AD594

Analog output

Supply voltage: from +5V to ±15V

Nominal Gain: 10mV/°C

Typical current sunk: <0.3 mA

Cold junction-compensation regulation

Resolution: ~0.3°C

A WIRELESS TEMPERATURE MEASUREMENT SYSTEM FOR ROTATING ELECTRICAL MACHINES

© ABB Group April 14, 2015


Page 06 of 15

lT-1305901

Two Xbee modules implement the wireless transmission of data to the PC.

ZigBee protocol, IEEE 802.15.4

ISM 2.4 GHz frequency band

16 channels data trasmission

A WIRELESS TEMPERATURE MEASUREMENT SYSTEM FOR ROTATING ELECTRICAL MACHINES

© ABB Group April 14, 2015


Page 07 of 15

lT-1305901

Transmitter:

Converts the analog voltage input in a 10 bit resolution digital value every 100 ms through its internal ADCs

Transmits five samples to the receiver...