Power Supplies, Inverters, UPS, Chargers, Electro Plating, Precision Welding-erosion, Coating Metals and many other Processes are made of high current circuits. Even in measurement of parameters like Micro-Ohm high currents are involved. Electronic Circuits are required in such products to give control to time, current, frequency and voltage in order to accomplish with the required precision a process or job.
In any power equipment, efficiency and reduction of bulk is crucial so SMPS and high frequency control is an important part of this domain. These products also generate EMI-RFI. Product Safety Study is also vital.
The MOC303XM and MOC304XM devices consist of a AlGaAs infrared emitting diode optically coupled to a monolithic silicon detector performing the function of a zero voltage crossing bilateral triac driver. MOC3041
They are designed for use with a triac in the interface of logic systems to equipment powered from 115 VAC lines such as teletypewriters, CTRs, solid-state relays, industrial controls, printers, motors, solenoids and consumer appliances, etc.
Simplifies logic control of 115 VAC power
Zero voltage crossing
dv/dt of 2000 V/µs typical, 1000 V/µs guaranteed
Motorola used to make these then it was Infineon Technologies now Isocom also makes it
These were used by me to make solid state relays. Look at the circuits here Power Electronics Circuits. The were used to control Heaters from DC control signal from a Proportional Temperature Controller. The Magnetic Contactors can be avoided for lower powers. At higher powers SCR banks become a bit expensive. The SSR has no mechanical wear and tear but heat up at high currents. So if we overrate by 5 Times then it is an excellent solution for lower power controls upto 5 Kilo Watts. The cycle time of Contactors must be 20-60 Seconds to make it last long. In a SSR a one second cycle time is possible as 10-20mS is the switching speed due to zero crossing.
“Sensitron is a privately held company, founded in 1969 and located on Long Island in Deer Park, New York.
Sensitron’s Motor Control expertise extends the usefulness of electronic technologies, bridging the gap between semiconductor devices and their systems usage. Sensitron’s capabilities include fully Integrated 3-Phase Brushless DC Motor Control Subsystem including power stage, non-isolated driver stage and controller stage.”
Electromagnetic Relays – NO – Normally Open when the relay is not energized or activated, this terminal is open-circuit.
NC – Normally Closed when the relay is not energized or activated, this terminal is closed circuit.
COM – The Common Center Terminal in relays. This is the center terminal that closes circuit with NC-NO.
The terminals are potential free and floating and are insulated from the control signals or coil windings by many kilo volts. Many provide visible isolation. These terms apply to SSR or Big Contacters too.
They are called SSR as there are made of semiconductors and have no moving parts to wear out. They do generate heat depending on load and switching. Thyristors are used in most as they are rugged, mosfets and IGBT may also be used for various applications.
In this section you will find SSR designs and PCB layouts which you can study. These were made and sold by me years ago. So the PCB layouts have gone thru some revisions and they worked quite well.
Many machines and equipment use some SSRs in their products which may need replacement. So the SSR is not only sold to OEMs but also to Service-Maintenance Market. These are also modified as Output Modules for digital outputs coming from embedded systems or Computers.
This is R-Y-B three phase 40A 440V AC Solid State Relay with 3-30 V DC Control Signal. It has Built in HeatSink and Fan. It is good for Controlling a Bank of heaters. This model could go upto 120A with SSR’s in parallel for Proportional Control. Solid State Relays SSR.
This is a Contacter replacement, it will switch R-Y-B phases. It is a high power SSR. In some places it is unwise to use an SSR, a Electromechanical Contacter will perform better. The merit of SSR is fast switching, no wear and tear. No dust humidity influence.
This was a Fire Retardant Plastic Box which was made for the SSR I/O Stackable Modules. DC Control for an AC Load. Usually it is to control another Big Three phase contactor;
Pneumatic or Steam Valve, Solenoids-Motors. When Mounted at the end of the PCB it offers over 2kV Isolation from the Digital Circuits. The Output 230V signals NO-NC, can control Light Loads like the Coil of a Big 230V Relay also called contactor.
It could be Mounted on a PCB by soldering or a Plugin Base. It is better to have Crimped connections or Terminals. A very good quality spring Loaded Socket may also work but it has to be rated for many operations. Things like Nickle Alloy Plated, Beryllium
Copper were the Materials Jargon. A contact resistance in the Terminals, a mismatch of alloys, electrochemical reactions, Corrosive Fumes, Brine or High Humidity can build a Loose connection into a Dangerous Sparking Contact.
Not only the Functionality of the SSR will be affected in a Sparking Contact, but a Risk of a Fire Developing. When Inflammable Materials or Volatile Liquids are Present Nearby, the risk is even greater. Read More –