Solid State Relays

Carlo Gavazzi is a market leader in solid state relay technology with one of the broadest range of products in the industry. With over 35 years of experience, Carlo Gavazzi knows what it takes to manufacture solid state relays that are designed to withstand the rigors of your toughest applications. With local sales and support centers located in 22 countries and independent distribution in over 100 countries, Carlo Gavazzi product and technical support is available around the world.

What is a Solid State Relay?

The terms solid state relay and solid state contactor are often used interchangeably and refer to an electronic switch with a solid state output such as an SCR, TRIAC, MOSFET or Transistor. Solid state relays have no moving parts and as such their life time is considerably longer than mechanical contacts - this makes them ideal in temperature control applications where their fast duty cycles ensure a more accurate temperature control. In addition, they use opto-couplers to provide isolation between the input and the output so there is no coil that can create voltage spikes on turn-off - which makes them more friendly to the low signal outputs typically found on temperature controllers. Inputs available include both Digital (AC and DC voltages) as well as analog (4-20 mA and 0-10 V).

We have prepared a series of Online Learning Modules to provide a good overview of the fundamental operation and applications for solid state relays. These training modules can be taken at your leasure and at the completion, you will receive a certificate.

CARLO GAVAZZI offers solid state relays for voltages up to 600 V and for currents up to 125 A. Our relays feature Direct Copper Bonding to provide improved protection against thermal stress and thereby providing an increased life and improved reliability. In addition our SSRs are available with or without a built-in heatsink.

In addition, Carlo Gavazzi offers relays with built-in monitoring for mains loss, load loss, SSR short circuit, open circuit and over-temperature with a relay output to allow measures to be taken immediately.

For applications where there are numerous zones, our NRG Series is the ideal switching solution when monitoring of the field level devices is required in order to minimize expensive equipment downtimes. In addition to the switching function, the NRG integrates monitoring circuitry to enable the exchange of data with the machine controller via Modbus RTU, PROFINET, EtherNet/IP™, EtherCAT, and Modbus TCP. Typical applications include plastic injection machines, PET blow moulding machines, packaging machines, semiconductor manufacturing machinery and glass tempering machines.

Our Product Range

Switching Types

Solid state relays allow for switching the load on at various times in the AC cycle - this allows them to minimize the first half cycle inrush current. The types of switching Carlo Gavazzi offers are :

• Zero Switching
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  • After the control signal is applied, the output switches on at the first zero crossing of the AC output voltage.
  • For switching resistive/ohmic loads (heaters, lights), capacitive loads and most motor loads.
• Random Switching
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  • After the control signal is applied, the output turns on immediately.
  • For switching motor loads and loads where a slightly quicker response time is required.
• Peak Switching
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  • After the control signal is applied, the output turns on at the first peak of the AC output voltage
  • For switching highly remnant inductive loads such as transformers
• Phase Angle Switching
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  • The output turns on at various point in the AC output voltage in accordance with the analog input signal
  • Typically used in heating applications where a very precise regulation is required or where the heater is very sensitive to thermal changes
  • Ideal for open loop temperature control
  • Control of heating lamps - no flickering
  • This switching generates significant electrical noise
• Burst Firing
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  • Is basically a zero crossing relay which time proportions the output based on the analog input signal. (ie. 50% = 1 second on, 1 second off....)
  • A 1 or 2 second time base is typically used so the temperature regulation is not as good as phase angle switching but there is less switching noise
• Distributed Full Cycle Switching
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  • Is a zero crossing relay but time proportions the output evenly along the time base. (ie. 50% = 1 AC cycle on, 1 AC cycle off....)
  • An excellent compromise between phase angle and burst firing. Reduced noise and excellent temperature regulation
• DC Switching Relays
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  • For switching DC loads such as motors, solenoids and battery charging systems

Applications