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Electric contacts

These are devices fitted on the pressure gauges and thermometers when requiring electric operation at preset values. They can activate visual or acoustic

alarms, or else actuate simple electromechanical units through a relay. They can be positioned over the entire scale while they come in two versions: normal

electric contact, electric contact with magnet. They are normally used in diameters 100 and 150 mm.

Characteristics:

Transparent hood:

Contact material:

Max approch of set points, with normal contacts:

Max additional error, with normal contacts:

Max number of breaks at max. resistive capacity:

Temperature limits:

polycarbonate

Ag/Ni alloy gold plated μm

2% of full scale value / with magnet 3% of full scale value

1% of full scale value / with magnet from 1 to 4 % of full scale

5 x 10

4

Ambient -20 +60° C

CONTACT LOAD CAPACITY IN mA

SWITCHING FUNCTIONS OF ELECTRIC CONTACTS

NORMAL CONTACT (MAX. CURRENT INTENSITY 0,4A)

V

~

—

MAX. INDUCTIVE LOAD

230

45 mA

40 mA

25 mA

110

90 mA

80 mA

45 mA

48

170 mA

120 mA

70 mA

24

250 mA

200 mA

100 mA

NORMAL MAGNET (MAX. CURRENT INTENSITY 0,6A)

V

~

—

MAX. INDUCTIVE LOAD

230

120 mA

100 mA

65 mA

110

240 mA

200 mA

130 mA

48

450 mA

300 mA

200 mA

24

600 mA

400 mA

250 mA

Notes

The magnet-actuated contact attracts

the instrument pointer when close

to the point of contact; it prevents

sparking, with consequent rusting and

disordered repetition of commands.

It is normally used in the presence of

vibrations. However it is recommended

to use a relay in the presence of heavy

loads. Platinum is a material with

excellent chemical resistance.

Its hardness and resistance to electric

wear considerably reduces the

tendency of sticking contacts;

therefore it is suitable for high

ambient temperatures.

SWITCHING

SCHEME

SWITCHING

DIAGRAM

PART. No

SWITCHING FUNCTION

1 NA

SINGLE CONTACT

1) CONTACT CLOSES

1 NC

SINGLE CONTACT

1) CONTACT OPENS

2 NC NA

TWO CONTACTS

1) CONTACT OPENS

2) CONTACT CLOSES

2 NA NC

TWO CONTACTS

1) CONTACT CLOSES

2) CONTACT OPENS

2 NC NC

TWO CONTACTS

1) CONTACT OPENS

2) CONTACT OPENS

2 NA NA

TWO CONTACTS

1) CONTACT CLOSES

2) CONTACT CLOSES

2 I NC NA

TWO CONTACT WITH INDEPENDENT CIRCUITS

1) CONTACT OPENS

2) CONTACT CLOSES

2 I NA NC

TWO CONTACT WITH INDEPENDENT CIRCUITS

1) CONTACT CLOSES

2) CONTACT OPENS

2 I NC NC

TWO CONTACT WITH INDEPENDENT CIRCUITS

1) CONTACT OPENS

2) CONTACT OPENS

2 I NA NA

TWO CONTACT WITH INDEPENDENT CIRCUITS

1) CONTACT CLOSES

2) CONTACT CLOSES

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