Electric Motor Star and Delta Connection Diagrams

by Editor on August 17, 2012

These diagrams show the basic 3 phase electric motor coil winding configurations for Star and Delta connections.

The first shows that a Star connected motor will draw less current than when it is connected in Delta.

Motor Star and Delta Connections 300x131 Electric Motor Star and Delta Connection Diagrams

(Double ckick the image twice to enlarge)

The diagram below shows the actual wiring and link connections for both Star and Delta to a typical Squirrel Cage electric motor.

Note that most electric motor coil windings are labelled U,V and W and the end of each winding is indicated as 1 or 2 ie. U1-U2…

When wiring the motor you will need to fit the links in the motor connection box to configure them for either Star or Delta. The link connections options are normally shown on the motor or inside the connection box lid.

Most basic fan motors will be connected for Star configuration.

To change the direction of the motor simply swap any two phase connections.

Electric Motor Star and Delta wiring and link Connections 206x300 Electric Motor Star and Delta Connection Diagrams

Star Delta Motor Starter

Where a Star Delta Motor Starter is used all 6 motor terminals are connected as per the wiring diagram of the starter unit.

The motor will be started in Star and switch to Delta when the motor reaches its normal running speed.

This is to reduce the start-up current draw of the motor which can be up to 4 times the running current.

Thanks for the diagram to: Rotor UK Ltd. 16 Everitt Close, Denington Industrial Estate Wellingborough NN8 2GF

More info about Electric Motors.


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{ 2 comments… read them below or add one }

Onota Adeiza January 13, 2013 at 08:46

This is a one stop solution. it has really helped. regards.

Andy Ward November 16, 2012 at 10:44

Thanks for giving sparks this blog.
It’s a really useful source of info.

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