Speed And Direction Control of Motor

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Discussion Overview

The discussion revolves around the control of speed and direction for AC motors, specifically single-phase and three-phase motors, in comparison to DC motors which utilize H-bridges and PWM for control. Participants explore various methods and technologies applicable to AC motor control.

Discussion Character

  • Technical explanation
  • Exploratory
  • Debate/contested

Main Points Raised

  • One participant mentions the use of H-bridges for DC motors and queries how to control speed and direction for AC motors.
  • Another participant suggests that a Variable Frequency Inverter (VFI) drive would be an effective solution for controlling AC motor speed and direction.
  • A participant questions how a VFI would function in comparison to H-bridges, particularly regarding frequency changes in three-phase motors.
  • It is proposed that the direction of a three-phase motor can be altered by swapping two of its three phases, and that speed can be adjusted by changing the AC frequency or supply voltage.
  • One participant references a resource that discusses the possibility of using PWM to create a sine wave of variable frequency for AC motors.
  • A later reply indicates familiarity with the theoretical procedure of using PWM with a sine table for AC motor control.

Areas of Agreement / Disagreement

Participants express various viewpoints on the methods for controlling AC motors, with no consensus reached on the best approach. Multiple competing views remain regarding the effectiveness and implementation of different technologies.

Contextual Notes

Some limitations include the dependence on specific motor types and configurations, as well as the need for further clarification on the practical implementation of the proposed methods.

ENE
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Hello,
In case of DC we use H-Bridges To control Dc motor direction and Speed with PWM.
But in case of AC motor Single phase and 3 phase motor how to control Speed and direction?
 
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Hi...
I reckon your best bet would be a Variable Frequency Inverter drive.
 
How it will work i mean in H bridges there is mosfet with PWM channel.
in the we will change the frequency of 3 phase how?
 
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Likes   Reactions: RNickl
You can shift the direction of an 3 phase motor by swaping two of its three phases. The speed depends on how hast the stator magnetic field rotates. So you can change the AC frequency if possible or change the supply voltage, but i recommend someone who works with electrical machines to reply to you.
 
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Hello,
I know the theory procedure we use PWM with sin table in look up i think
 

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