Faq Sections

How to define a relay for a three-phase motor load?

Example :

U: 400V
P: 15KW
Efficiency: 0,8 for a motor < 5KW
Efficiency: 0,9 for a motor > 5KW
Power factor: 0,8 for a motor < 5KW
Power factor: 0,9 for a motor > 5KW
V3 = 1,732

Nominal current absorbed by the motor:

I = 15000 = 26,7 A
----------------------------
400 x 1,732 x 0,9 x 0,9

The current rating of the relay must be 4 x I of the motor in order to withstand starting currents:
>>> 106,8 A >>> it's necessary to take a 125 A relay.

Advantages of Solid State Relays (SSR) over Electro-Mechanical Relays (EMR)

With their semiconductors and a technology-based design, SSRs are more reliable, have a longer service life and less electromagnetic interference (EMI) than EMRs. They also have faster response times and are vibration and shock resistant, when compared to the EMR equivalent. This is because SSRs have no mechanical contacts to wear out or an arc, which is the primary cause for EMR failure.

Protecting AC Solid State Relays (SSRs) : voltage & current protections

How to select the appropriate Heatsink ?

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Installation without a heatsink or installation on the back plate of a cabinet

A curve without a heatsink is associated with SO/SC or SG types of solid state relays. When installed on the back plate of a cabinet, it is essential that the relay/plate contact is correct. A 150 mm x 150 mm x 3 mm aluminium back plate corresponds to approximately 4°/W. A 300 mm x 300 mm x 3 mm aluminium back plate corresponds to approximately 2°/W. In any case, we recommend testing and measuring the heat dissipation. A steel plate has greater thermal resistance.

Magnetic proximity sensors

What is a magnetic sensor?

The sensitive element of the magnetic sensor can be a Hall effect cell, a magnetoresistance or a reed switch detecting the presence of a magnetic field, generally a permanent magnet. It detects without contact the position of the magnet and transmits an electrical signal.

Which level sensor to use in chlorinated water?

Polyamide level sensors can be used in low chlorinated water such as swimming pools but polypropylene sensors are more suitable.

See our level sensors

What to do when in the application there is a problem of level agitation?

When in the application there is a problem of agitation of the level (wave effect) it is necessary to put the detector in an anti wave system. Generally this system consists of a closed tube which envelops the detector and which is pierced with at least 2 holes (it is necessary to think of the evacuation of the air when the level rises).

The smaller the holes, the greater the difference between the real level and the level inside the tube: it is therefore necessary to find the right compromise: eliminating waves and good level monitoring.

Benefits of REED bulb sensors ?

The main advantages are:

No power supply required. No current consumption in open state with real galvanic isolation and no voltage drop in closed state.
Works in difficult environments: wide temperature range, insensitive to dust, water projections, ...
The detection distances can be very large. They will depend mainly on the magnetic sensitivity of the bulb and the power of the magnet as well as the magnetic environment of the couple Reed Switch + Magnet.
Very economical compared to all other technologies.