A three-phase induction motor has a kind of electrical “resistance” when it starts, which makes it draw too much electrical current when you turn it on.
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When you first turn it on with the normal power supply, just like in regular transformers, it pulls a lot of electricity for a short time.
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we have different ways to start these motors more safely and smoothly -
1. Direct-On-Line (DOL) Starters: Small three-phase induction motors can be started directly by connecting them straight to the power supply.
These methods are often referred to as “reduced voltage methods” for starting squirrel cage induction motors. There are a few ways to do this: 1. By using primary resistors 2. Autotransformer 3. Star-delta switches
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Slip-ring motors are a type of motor that can be started at full power right away. This is because they have a special feature called slip-rings.
To control the speed of a three-phase motor, there are different methods we can use. These methods include things like changing the number of poles, adjusting the voltage that goes to the motor’s main part (stator),
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This method is commonly used with squirrel-cage induction motors. Here’s what’s good about it: – It provides strong and stable performance. – It’s very efficient because there’s no energy wasted as heat. – It’s easy to set up and control, and it’s cost-effective.
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This method involves modifying the rotor resistance, offering a straightforward approach to speed control.
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Cascade speed control, which uses a circuit with SCR (Silicon Controlled Rectifier) inverters, offers several benefits.
Variable frequency speed control stands out as a highly efficient and precise method for adjusting motor speed.
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