Introduction to Industrial Automation

Figure 2.16  Single-throw and double-throw electric contacts for several numbers of poles.

---

36

 

◾

  Introduction to Industrial Automation

coil winding around a cylindrical tube, a ferromagnetic “plunger” that is free to move or slide IN 

and OUT of the coil’s body and optionally a return spring. In the case of the absence of a return 

spring, an external return action is necessary. In general, solenoid actuators may be used either as a 

holding mechanism under continuously supplied voltage or as a latching mechanism under pulse-

type (ON-OFF) supplied voltage. Linear solenoid actuators are available in a variety of types, 

forms, applied forces, voltages of operation, and other attributes, while the selection of the most 

suitable and efficient types is dependent on the kind and the specific characteristics of the applica-

tion. Some linear solenoid actuators, designed to perform a specific task in circuit breakers, will 

be presented in the section on specific industrial equipment.

Plug-in socket mounting

Plug-in socket mounting

Technical information for general purpose relay type 55.32 by finder, (above left)

Rated current/maximum peak current

Contact configuration

Rated voltage/maximum switching voltage

Rated load AC1

Rated load AC15 (230 V AC)

Single phase motor rating (230 V AC)

Breaking capacity DC1: 30/110/220 V

Minimum switching load

Standard contact material

Coil specification

Contact specification

Nominal voltage (U

N

)

Rated power AC/DC

Operating range

Holding voltage

Must drop-out voltage

Technical data

Several other technical data, such as mechanical life, electrical life, operate/release time,

dielectric strength, ambient temperature range, etc., are also given by manufacturers of

general purpose relays.

A

V AC

VA

VA

kW

A

W (V/mA)

V AC (50/60 Hz)

V DC

VA (50 Hz)/W

AC/DC

AC/DC

AC/DC

2 CO (DPDT)

10/20

250/400

2500

500

0.37

10/0.25/0.12

300 (5/5)

AgNi

6-12-24-48-60-110-120-230-240

6-12-24-48-60-110-125-220

1.5/1

(0.8 ... 1.1)U

N

/(0.8 ... 1.1)U

N

0.8 U

N

/0.5 U

N

0.2 U

N

/0.1 U

N

PCB mounting

A1

A2

12 11 14

12 21 24