[PIC] Understanding the Logic Behind a 3-Phase Autostarter: Circuit Diagram Analysis and ADC Implementation

Recent discussion might help:

Hello fellow forum members,

I'm seeking assistance in understanding the logic behind a 3-phase autostarter circuit. I've attached a circuit diagram (photo) to provide a visual reference for discussion purposes.

In this circuit, I noticed that the 3-phase inputs are directly connected to a microcontroller (MCU) via two series resistors. The MCU utilizes its built-in ADC (Analog-to-Digital Converter), with one phase serving as a reference and the other two phases as input signals.

My main question revolves around the mechanism by which the MCU detects and interprets the 3-phase inputs using this configuration. I'm particularly interested in comprehending the logic and steps involved in the ADC implementation for this autostarter circuit.

I would greatly appreciate any insights, explanations, or resources that can shed light on the functioning of this circuit. Feel free to provide explanations, diagrams, or even code snippets if they can help illustrate the concept effectively.

Thank you in advance for your valuable contributions!

Note: Please ensure that your responses are clear and detailed, as I am keen to gain a comprehensive understanding of the topic.

Hi,

The schematic is a mess.
The circuit is against a lot of electronics design rules.(power supply, bypass capacitiors, uC input voltage range...)

And I doubt that your information about ADC usage is true ... I can't see how this should be able to work as described.

My recommendation:
* contact the person who drew this schematic
* or use a more reliable schematic

Klaus

Detect time between consecutive peaks (positive polarity) of phase #1 (reference). Time between two peaks tells you motor speed.

Peaks of three waveforms should be spaced 120 degrees apart.

May be helpful the link