Sords Electric sells Solid State Relays (SSR) by Carlo Gavazzi.
A Solid State relay( SSR ) is an electrical switch that opens and closes under the control of another electrical circuit. A solid state relay( SSR ) is a solid state electronic component that provides a similar function to an electromechanical relay but does not have any moving components, increasing long-term reliability. With early SSR's, the tradeoff came from the fact that every transistor has a small voltage drop across it. This voltage drop limited the amount of current a given SSR could handle. As transistors improved, higher current SSR's, able to handle 100 to 1,200 amps, have become commercially available.
A solid state contactor is a very heavy-duty solid state relay, including the necessary heat sink, used for switching electric heaters, small electric motors and lighting loads; where frequent on/off cycles are required. There are no moving parts to wear out and there is no contact bounce due to vibration. They are activated by AC control signals or DC control signals from Programmable logic controller (PLCs), PCs, Transistor-transistor logic (TTL) sources, or other microprocessor and microcontroller controls.
Solid-state relays ( SSR's ) control load currents through solid-state switches such as triacs, SCRs, or power transistors. These elements are controlled by input signals coupled to the switched devices through isolation mechanisms such as transformers, reed relays, or optoisolators. Some solid-state relays also incorporate snubber circuits or zero-crossing detectors to reduce spikes and transients generated by interrupting load current. Since semiconductor switches can dissipate significant amounts of power, solid-state relays must generally be heat sinked to minimize operating temperature.
SSRs generate heat because of the voltage drop present in all semiconductor devices. A 40-A relay, for example, typically drops 1.2 V during conduction and, thus, dissipates 50 W of heat. However, SSR heat generation generally does not require special system design. These devices usually mount on circuit boards or control panels containing other semiconductor devices. Cooling and heat-sinking methods used for these devices are likely to be adequate for the SSR.
Some SSRs designed for controlling ac loads incorporate a zero-voltage turn-on circuit that switches the load on or off only when the power-line sine wave passes through zero. Highly capacitive loads such as lamps and heaters which produce high inrush currents at turn on generate little electromagnetic interference if actuated when line voltage is zero. However, inductive loads such as motors and transformers can saturate during the first half cycle after turn on and produce maximum interference when switched on as line voltage passes through zero. Zero-voltage switches should not be used.
Carlo Gavazzi offers a comprehensive range of solid state relays (SSR’s) featuring direct copper bonding technology for increased life and reliability. SSR’s are used extensively in the plastics, packaging, food processing, and HVAC industries - primarily for temperature control. They are the logical replacement for mercury contactors.
Other applications include lighting and pump switching. Furthermore, many of our relays feature horsepower ratings making them suitable for controlling motorized dampers in HVAC control systems - where their long life and noise-free switching make them ideal replacements for mechanical contactors.
Carlo Gavazzi's range includes single phase relays up to 125 amps and 3 phase relays up to 75 amps. They are available with both digital and analogue inputs (4-20 mA or 0-10 V) Furthermore, we also offer a complete range of SSR's with a built-in heatsink.
A Solid State relay( SSR ) is an electrical switch that opens and closes under the control of another electrical circuit. A solid state relay( SSR ) is a solid state electronic component that provides a similar function to an electromechanical relay but does not have any moving components, increasing long-term reliability. With early SSR's, the tradeoff came from the fact that every transistor has a small voltage drop across it. This voltage drop limited the amount of current a given SSR could handle. As transistors improved, higher current SSR's, able to handle 100 to 1,200 amps, have become commercially available.
A solid state contactor is a very heavy-duty solid state relay, including the necessary heat sink, used for switching electric heaters, small electric motors and lighting loads; where frequent on/off cycles are required. There are no moving parts to wear out and there is no contact bounce due to vibration. They are activated by AC control signals or DC control signals from Programmable logic controller (PLCs), PCs, Transistor-transistor logic (TTL) sources, or other microprocessor and microcontroller controls.
Solid-state relays ( SSR's ) control load currents through solid-state switches such as triacs, SCRs, or power transistors. These elements are controlled by input signals coupled to the switched devices through isolation mechanisms such as transformers, reed relays, or optoisolators. Some solid-state relays also incorporate snubber circuits or zero-crossing detectors to reduce spikes and transients generated by interrupting load current. Since semiconductor switches can dissipate significant amounts of power, solid-state relays must generally be heat sinked to minimize operating temperature.
SSRs generate heat because of the voltage drop present in all semiconductor devices. A 40-A relay, for example, typically drops 1.2 V during conduction and, thus, dissipates 50 W of heat. However, SSR heat generation generally does not require special system design. These devices usually mount on circuit boards or control panels containing other semiconductor devices. Cooling and heat-sinking methods used for these devices are likely to be adequate for the SSR.
Some SSRs designed for controlling ac loads incorporate a zero-voltage turn-on circuit that switches the load on or off only when the power-line sine wave passes through zero. Highly capacitive loads such as lamps and heaters which produce high inrush currents at turn on generate little electromagnetic interference if actuated when line voltage is zero. However, inductive loads such as motors and transformers can saturate during the first half cycle after turn on and produce maximum interference when switched on as line voltage passes through zero. Zero-voltage switches should not be used.
Carlo Gavazzi offers a comprehensive range of solid state relays (SSR’s) featuring direct copper bonding technology for increased life and reliability. SSR’s are used extensively in the plastics, packaging, food processing, and HVAC industries - primarily for temperature control. They are the logical replacement for mercury contactors.
Other applications include lighting and pump switching. Furthermore, many of our relays feature horsepower ratings making them suitable for controlling motorized dampers in HVAC control systems - where their long life and noise-free switching make them ideal replacements for mechanical contactors.
Carlo Gavazzi's range includes single phase relays up to 125 amps and 3 phase relays up to 75 amps. They are available with both digital and analogue inputs (4-20 mA or 0-10 V) Furthermore, we also offer a complete range of SSR's with a built-in heatsink.
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