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Highly Reliable Switching from New Weidmüller Single-Phase Power Solid-State Relays
- Published: Tuesday, 27 August 2013 15:48
Developed specifically for the diverse requirements of the process industry, railway applications and machine and plant manufacture, the new Weidmüller single-phase Power Solid-State Relays (PSSR) modules stand out from electromagnetic relays due to highly reliable switching throughout their long lifecycle, a compact design, low drive power, and short response times.
The PSSR switches are simply snapped onto the mounting rail and connected. They load silently and without contact bounce, and are highly resistant to shock and vibrations. Adjacent assemblies are left undisturbed as there are no electromagnetic emissions or switch sparks during the switching process.
The solid-state relays are used to switch high AC loads with thyristors or triacs to create no-voltage switches (solid-state type). They are available with pre-installed heat sinks, with control voltage and output current combinations of 24VDC/25A, 24VDC/35A, and 230VAC/25A.
The Weidmüller PSSR portfolio includes a control unit for single-phase Power Solid-State Relays. This is simply plugged into the PSSR and is able to control the current on up to five parallel consuming loads in parallel connection, which are programmed via the teach key that is found on the module itself or on an external teach input. The module sets off an alarm if the current falls below 16 percent of the rated value and the control unit also features a wide variety of diagnostic functions, such as detecting short circuits, disconnections and faulty loads.
The PSSR family also includes the PSSR “hockey pack” - single-phase modules without heat sinks. These feature a cooling surface for a no-voltage switch. With 24 VDC control voltage, the modules are available with 50A or 75A output current and a switch voltage of up to 600VAC. The "hockey pack" is particularly useful for trace heating in the process industry.
The Weidmüller PSSR range also comprises a single-phase "70A phase-fire controller" module, which uses an analogue proportional regulator for phase-firing. This can be manually adjusted within the range of 47...100 Hz. The PSSR has a 4…20mA gate current (+/- 15%) process signal, which is typically used on the input side in the process industry, and a 70A switching current. Possible applications include the speed setting on single-phase motors and the building of regulators for heaters and lights.
Weidmüller also offers two variants of triple-phase PSSRs with ready-to-use heat sinks with no-voltage switches - the PSSR 24VDC/3PH AC 20A and the PSSR 230VAC/3PH AC 20A.
The single-phase PSSR modules function freely in ambient temperatures of -55°C to +100°C, while the control unit and the triple-phase modules work freely in a range of -40°C to +80°C. Weidmüller PSSRs are CE-certified and cURus certification is underway. The PSSR modules comply with the current standards of EN 60947-4-3, EN 60950 and IEC 60335-1.