3 phase motor star delta connection:

This diagram shows how to make 3 phase motor star delta connection. In this circuit, we use a DP MCB ( Double Pole Minature Circuit Breaker ), 3 magnetic contactors, an overload relay, a start switch, and a stop switch. First, we need to connect the DP MCB with the power source, then connect the all magnetic contactor with the power source, then connect the start and stop switches.


Diagram of 3 phase motor star delta connection:

3 phase motor star delta connection

Components needed For this Project:

You can get the components from any of the sites below:

  1. DP MCB 10A [See Buy Click Amazon]
  2. Magnetic Contactor 40A [See Buy Click Amazon]
  3. Motor Protector Overload [See Buy Click Amazon]
  4. Push Button NO Switch [See Buy Click Amazon]
  5. Push Button NC Switch [See Buy Click Amazon]

*Please note: These are affiliate links. I may make a commission if you buy the components through these links. I would appreciate your support in this way!

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Components used to make the 3 phase motor star delta connection:

01. DP MCB:

DP MCB In 2 Pole MCB, switching & protection is affected in phases and the neutral. A Double Pole or DP Switch is a Switch that Controls 2 Circuits at the same time. In terms of Residential Switching, this Normally means it Switches the live and Neutral at the same time. In Layperson Terms, Double Pole switches or DP Switches are Exclusively Designed to Control 2 Different Electrical Circuits at the same time, which allows the Appliances to Isolate safely and reliably. Fan or light Combinations and Medical Equipment are some of the many applications for DP Electrical Switches and Electrical components.

02. Magneti Contactor:

A magnetic contactor is an electromagnetic switching device. It is generally used for controlling 3-phase Motors. The operation of a magnetic contactor is similar to that of a Relay. but a relay is used for low-power or low-voltage connections, and a magnetic contactor is used for high-power or high-voltage connections. As soon as the supply is applied to the magnetic contactor coil. its normally open contacts are closed and normally closed contacts are opened and the associated devices are also operated. This is how a magnetic contactor works.

03. Overload Relay:

Overload Protection is Protection Against a Running Overcurrent That Would Cause Overheating of The Protected Equipment. Hence, An Overload is Also a Type of Overcurrent flow. Overload Protection Typically Operates on an Inverse Time curve where the Tripping Time Becomes less as the Current Increases. This Overload Protector is an Essential Component for Many Sockets Power Systems. The Top-Quality Overload Protector can Effectively Protect Electrical Products from Power Surges.

04. Start Switch:

NO (Normally Open) Terms Refer to a Type of Dry Contact or Wet Contact. A Push to Make Switch Allows Electricity to flow Between its 2 contacts when held in. When the button is released, the Circuit is broken. This type of Switch is also known as A Normally Open (NO) Switching system. As its name implies, a Normally Open (NO) Switch Contact or “a Contact” is a Switch. Put very simply, a Normally Open Sensor will have no Current When in a Normal State But When it Enters an Alarm State it will have +5V applied to the Circuit.

05. Stop Switch:

An NC (Normally Closed) Push Button is a Push Button That, In Its Default State, Makes Electrical Contact With The Circuit. An NC (Normally Closed) Push Button is a Push Button that, in its Default State, Makes electrical Contact With the Circuit. When The Button Is Pressed Down, The Switch no Longer Makes Electrical Contact And The Circuit is Now Open. When The Button is Not Pressed, Electricity Can Flow, But When it is Pressed The Circuit is Broken. This type Of Switch is Also known As a Normally Closed (NC) Switch.

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Frequently asked questions

How do you connect a three-phase motor in Star and Delta?

Now let's see how you can connect the motor windings in a star or delta connection. For the star connection, you just need to connect the lower and ends of the windings U2, V2, and W2. If you then connect U-1 to W-2, V-1 to U-2, and W1 to V-1, the winding connection will be in the delta.

How many connections are required at a 3-phase motor when using a star-delta?

If a 3-phase motor has six wires at the terminal box it can be connected in star or delta, the voltage suitable for each option would be on the nameplate. If there are only three wires then it is only suitable for one voltage which would also be on the nameplate.

Why is a star-delta Connection used in motors?

One of the reasons why Star-Delta starters are used is because of the lower starting current in the Star connection stage, which provides less starting torque and puts less mechanical or electrical stress on the system, thereby increasing its lifespan.

What is a star-delta Connection?

A Star Connection is a 4–wire connection (4th wire is optional in some cases) A Delta Connection is a three–wire connection. 2 types of Star Connection systems are possible: 4–wire, 3-phase system, and 3–wire three-phase system. In Delta Connection, only a 3 – 3-wire 3-phase system is possible.

Why the 3-phase voltage is 400 volts?

In a 3x400 V 3-phase system, the voltage difference between each phase wire and the neutral was always 230- V, while the voltage difference between 2 phase wires was 400- V. This makes it possible to supply both the house with 230- V and machines that require 400 V (some electric diagram car chargers for the example).

Read more Single Phase Wiring


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