The evolution of the SSRs : From the hockey puck to the 22.5mm relay

gammes relais statiques

Since they were launched on the market in the early 1970s, solid state relays ( SSR s) have been evolving, covering a  wider range of applications, from the industrial sectors up to demanding applications in the railway, aircraft and medical industries. There are several well known benefits of solid state switching technology that make SSRs better suited than electromechanical devices on certain type of applications. Here are just a few of them: no mechanical swithcing mechanism (which translates into a longer lifespam), no electrical arcing, quiet operation, low power consumption, high resistance to shock and vibration and fast switching (for better process control : a very accurate adjustment).

In terms of mechanical layout and dimensions of solid state relays, there are several housing  that have become industry standard, the most popular one is the hockey puck style housing. Now you can find different package styles allowing the SSRs to be mounted in several different ways, depending on the preferences and the space availability of the user, such as: panel mount, DIN Rail mount and PCB mount.

Single phase SSRs different housing types

The “hockey puck” package, the most common package style

relais okpac sThis type of SSR is for panel mount. This package has been extremely popular because it can be easily mounted and it can handle currents ranging up to 125 Amps (when mounted on a suitable heatsink). Celduc® relais’ popular range of « hockey puck » SSR is the okpac® range, introduced in 2004.

celduc’s okpac range

For many years now, there is an increasing need for compact solutions. This trend has led celduc® to market a new 22,5mm pitch SSR range.

The 22.5mm wide SSR solution

sa and su rangeOur celpac® range is for both DIN rail mount and panel mount applications. Thanks to its compact housing you can save space when compared to standard hockey puck SSRs. This solution is to prioritize when the current to be switched is not very high.

Celpac® range is available with different connection types : screw connection on inputs (SA range) or with pluggable connector on inputs (SU range). Available in AC and DC output versions, these Solid State Relays offer multiple, simple and fast connections in 2 mounting package styles : Panel and DIN rail mount.

Our brochure presenting the celpac range

Din Rail mount SSR

DIN rail is a method of mounting electrical devices.

Our celpac® range is also available in « ready to use » versions with built-in heatsinks (SAL/SUL/SAM/SUM versions). All celduc® DIN Rail solid state relays are designed to fit on a standard 35mm wide symmetrical DIN Rail. Celduc® provides the optimal « low profile » DIN rail relay for your application !


PCB mount SSR

A PCB relay is ideal to use in applications where a small, power-dense package is required, as is the case with a lot of commercial and industrial equipment.

celduc offers an extensive line of PCB mount Solid State Relays.  SK range available in different models :

  • SKA pcb relaySKA range (AC output) up to 6A 230 or 400VAC, with built-in voltage protection, ideal for solenoid or motor control

  • SKL bcp relaySKL range with thyristor rating from 16A to 75A. This range is ideal for applications with high inrush current. Nominal currents depend on the heatsink used and are limited by the PCB (25A/30A)

  • SSKD range (DC output – Bipolar technology) up to 3A 60VDC or 200VDC
  • skld pcb relaySKLD range (DC output – MOSFET technology) up to 12A 36VDC or 60VDC

You will for sure find your ideal solution within celduc’s products range. Just try them : you will not get rid of our relays easily !

To go further : read our article “How to select the right solid state relay?”