Level switches

A level switch is a level sensor, which switches an electrical contact (open or close) when fluid level in a tank reaches a set threshold.

Therefore, reaching the preset level is converted into an on/off electrical signal, which can be used for instance to inform low level or overflow, trigger alarms, or start machines.

Level sensors are frequently used in several applications, such as oil hydraulics, automotive, medical and food industry, domestic appliances, etc.

Electromagnetic level switches

An electromagnetic level switch works without any power supply, being the electrical contacts potential-free.

The electromagnetic level switch includes a reed contact, which is a special switch that can be closed or opened by a magnetic field. The reed contact is placed inside the stem at the distance where the level threshold is to be set.

When the float that includes a magnet reaches the position of the reed contact, the magnetic field closes or opens the contact.

The float moves up when the level of fluid increases and moves down when the level of fluid decreases. The movement of the float is normally limited by a mechanical stop.

The electrical contact will switch back when the fluid level reaches back the threshold value.

To switch a contact from NO to NC or vice versa, it is usually enough to invert the float.

The level threshold is not adjustable, and is defined according to the stem length.

Euroswitch series mod P3x are electromagnetic level switches. These level sensors are in the market since many years, proving to be robust and reliable.

Adjustable level switches (modular level switches)

The float on adjustable level switches is firmly attached to the bottom of the stem with a nut. Hence, when the level of fluid increases the stem moves up, and when the level of fluid decreases the stem moves down.

The movement of the stem switches mechanically the electrical contact placed on the upper side of the level switch.

Therefore, the level threshold can be easily adjusted by cutting the stem at the desired length, with the following steps:

1. Remove the float from the stem.
2. Cut the stem at the desired length.
3. Attach the float to the bottom of the stem again.

Euroswitch series mod IMM are adjustable level switches. This level sensor is today the most practical solution in those cases that stem length might change according to the project needs.

Hysteresis of a level switch

The hysteresis is the difference between the switching point when level is rising, and the switching-back point when level is falling. The hysteresis of a level switch is a function of its design and structural layout. The hysteresis in level switches is normally very small, but it can be increased if necessary using special contacts.

Materials of a level sensor

Materials used in a level sensor will depend on the fluid type (media), which is used.

Electrical contacts of level sensors

A level switch can have a normally open (NO), normally closed (NC), or changeover (SPDT) electrical contacts.

Rated and maximum voltage and current have to be respected, in accordance to the manufacturer’s specifications.

It is highly recommended to use an electrical relay to separate the control circuit (where the level sensor operates), from the power circuit with its bigger loads and currents.

Responsibility in selection of level sensors

The specifications on medium compatibility cannot be generalized as they pertain to the materials used by the manufacturer. The information cannot be used for all application scenarios.

Testing the suitability of a Euroswitch level sensor for a specific application rests under the responsibility of the user. It may be the case that suitability can only be verified with appropriate field-testing.

Euroswitch level sensors

Euroswitch level sensors are manufactured in Italy (EU) according to highest quality standards. Euroswitch level switches are designed for the most challenging applications, providing exceptional reliability and durability. Please choose your Euroswitch level switch with the filters offered in this website.