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Motor Temperature Sensor

Introduction

Temperature sensors in motors are the ideal way to monitor the motor's health and avoid over-temperature damage to the motor and its components.

Wiring

Thermistors can be wired to any of the analog inputs (Throttle/Analog Input 1, Brake1/Analog Input 2, Brake2/Analog Input 3 or ABMS/Analog Input 4) depending on the whether an NTC or PTC thermistor is used.

Note

Firmware version 6.022 and below can only have NTC temperature sensors and wired to Brake2/Analog Input 3.

For NTC (resistance decreases with temperature increase)

Motor temperature on Brake2

For PTC (resistance increases with temperature increase)

Motor temperature on throttle

Configuration

  1. Enable Features bit 5 Motor temp sensor enable.

  2. Select the Motor temperature source.

  3. Enter the motor temperature sensor voltage for each of the following:

    1. Temperature feedback V at 0 C

    2. Temperature feedback V at 25 C

    3. Temperature feedback V at 50 C

    4. Temperature feedback V at 75 C

    5. Temperature feedback V at 100 C

    6. Temperature feedback V at 125 C

The thermistor datasheet can be used to estimate the motor temperature sensor voltage for each temperature.

Thermistor Voltage Calculator

Note

The temperatures outside of 0 °C through 125 °C are linearly extrapolated for temperatures above 125 °C and below 0 °C.

Troubleshooting

  • There is a lot of fluctuations in my motor temperature

    If using the Hall ground, the thermistor output can be affected by high frequency noise resulting in fluctuations in the temperature readings

  • How can I test if my voltage values are correct?

    The simplest way to test the accuracy of the temperature feedback involves using a hand-held thermometer and two known temperatures such as ice water and boiling water following the steps below. Verify motor temperature in BACDoor® matches the expected temperature on your thermometer, i.e. ~0 °C for ice water or ~100 °C for boiling water.