PRESSURE SWITCHS

VACUUM SWITCH

In the NORMALLY OPEN (NO) version (Fig. 4), the contact is open, i.e. there is no flow of current in the absence of pressure. When the pressure setting is reached, the electrical contact closes.
The picture in Fig. 5 shows a pressure switch with NORMALLY CLOSED (NC) contacts in the absence of pressure. We can see that, in the absence of pressure, contacts are closed and the signal is present on the external contacts. When the pressure setting is reached, the electrical contact rises and interrupts the signal.
In the SWITCHING CONTACT (SPDT) version (Fig. 6), the pressure of the fluid on the separating element (diaphragm or piston) causes a microswitch to switch over. Either NC or NO contacts, or both, can be used in this version.

35-35V	37-37V	357-357V
Vacuum switch ≤ 48V	Vacuum switch ≤ 250V	Vacuum switch ≤ 48V

377-377V	387
Vacuum switch ≤ 250V	Vacuum switch with switching contacts (SPDT)