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Monitoring Three Phase induction Motor Parameters using IOT

 

Introduction

 

I am sharing the email advice I gave recently to a student in India, on ideas for Induction Motor monitoring.

 

Induction motors are used widely in factories and on board ships, and the article is an overview of possible parameters that could be monitored.

 

 

Things to consider

 

Have you decided what parameters you wish to monitor.

Some possible suggestions for the induction motor monitoring are:

1) startup current - (is it the expected level, or higher indicating a possible fault, or lower / or no current, indicating power supply failure).

2) Full Load Current (FLC). - Is the motor running at FLC, and at the manufacturers stated levels?

3) Single Phasing Fault situations - (when one of the three phase wires becomes open circuit)

4) Vibration monitoring of the induction motor - This is sometimes done manually, on board ships for example using a portable vibration tester.
It could be built into the motor design instead, using vibration sensors.

5) Motor winding temperature sensing - Some Induction motors already have thermistors(resistance varies with temperature) built into their windings.


These thermistors are then connected to an Electronic type OCR (Over-Current Relay), which breaks the induction motor power supply, if the windings become too hot (more than manufacturers parameters).

You could instead, monitor the thermistor resistance output using an IOT system (either low data rate wireless, such as Zigbee, Lora, or directly wired to a IOT Internet gateway device).

6) Motor speed sensing - could be a useful parameter to monitor. Some Induction motors, such as those on ships, connected via an 'Autotransformer', can have variable speed settings. Therefore monitoring might be something you would wish to monitor.

7) Motor on/off states - Small Induction motors (< 10 Kw) use DOL (Direct On Line) starter systems. Larger motors, with higher current requirements, most commonly use 'Star-Delta' starting.

You could use IOT to monitor whether the starter was on or off.

8) All the above ideas, are concerned with monitoring the induction motor. You might also want to consider using IOT to remotely turn on / off the starter etc.

I hope this has given you some ideas / guidance.

Best wishes

Craig Miles

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Yesway Ltd is headed up by Craig Miles, BSc, PGCE, who most recently has taught HNC Industrial Control Systems, and also Marine Engineering, to worldwide students. Over nearly 30 years, Craig has worked for small wireless tracking startups, and a multinational aerospace business, in wireless communications systems development. The initiator of @ThingsLincoln, the Internet Of Things Network. Founder of Yesway Ltd, the two-way radio & Wireless Internet Of Things Company @acraigmiles