Introduction to Industrial Automation

Figure 3.20  Automation circuits for (a) permanent or (b) instant operation of a motor with two 

directions of rotation.

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Industrial Automation Synthesis 

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97

3.4.3   Automation of Various Motor Types

In Sections 3.4.1 and 3.4.2, the automation circuits for the most basic types of electrical motors have 

been presented in order to highlight the characteristics of these types of automations. In general, 

there are a lot of types of electrical motors, while every type of motor has its specifically designed 

automation circuit. These automation circuits are typical and standardized with respect to the manu-

facturing vendors, thus no more references to these circuits will be provided.  Subsequently, the most 

common types of electrical motor automations will be presented and, when needed, the engineer 

can directly refer to the standardized circuits for automation and operation of these electrical motors:

  1. With inversion and Y/

Δ

  2. With start through autotransformers

  3. With start through resistors

  4. With one direction of rotation and two speeds

  5. With two directions of rotation and two speeds

  6. Case (4) with an additional Y/

Δ

 start

  7. Case (5) with an additional Y/

Δ

 start

  8. With one direction of rotation, two speeds of rotation, and two internal coils

  9. With one direction of rotation and three speeds of rotation (one internal coil in a Dahlander 

connection and an internal simple coil)

  10. With two directions of rotation and three speeds

  11.  With one direction of rotation and four speeds (two internal coils in a Dahlander connection)

R S T

C

2

C

1

e

C

3

Μ

3 ~

N

C

1

50 Hz 230 V

R

Stop

Start 

e

C

1

C

3

C

3

C

3

C

2

C

2

C

1`

(a)

(c)

(b)

Y

Δ

Equivalent connection of windings

R

S

T

R

S

T

R

S

T

Δ: C

1

, C

2 

= ON

Y: C

1

, C

3 

= ON

R

S

T

R

S

T

I

Δ,Τ

I

Υ,Τ

I

Υ,Τ 

< I

Δ,Τ

Μ

Μ

Ο

Ο