Monday, June 02, 2008

EMI RFI Mains Power Filters

EMI RFI Noise Filters are required in two situations, to prevent EMI from an Electronic Equipment Like A Dimmer, Thyristor Drive, SMPS or Switcher affecting other Modules in a System or Neighboring Equipment.

The Second Situation is when a Sensitive Equipment Like a Medical Apparatus or Precision Measuring Instrument has to be Immune to any Noise from outside, as it can affect performance.

Sometimes it is Accuracy that can get affected, but some electrical jolts can damage or desensitize fine sensors or positioning systems.

EMI RFI Mains Power Filters

Filters are is connected in series with an Existing Mains Chord. It can also be Fixed in a Control Panel with a Clamp. The two X caps have higher Capacitance Value. The Y cap is Lower Value and withstands around 1kV,  It is better if X cap is AC 440V.

The common mode filter design in such a way that it cancels the noise. The correct winding polarity or direction is important for noise cancellation.

Related Resources

eEngineer - Electrical Engineering, EMI/EMC, RFI -  Introduction to EMI, EMC, RFI, Military EMC Standards, Radio Frequency Interference.

EMI Shielding RF Shielding - Tech-Etch designs and manufactures both standard catalog and customized shielding products.

Dealing with Computer generated RFI/EMI - Most of the time, the RFI generated is enough to render certain bands useless and on other bands, it may drown out any weak signals and distort or interfere with signals that you want.

TDK - Electronic Components & Materials - Electronic devices generate electromagnetic interferences, which can affect the proper functioning of electronic devices and systems

Here is one type i encountered in many T&M Instruments along with TDK too. It was Schaffner - electromagnetic compatibility - International leader in electromagnetic compatibility (EMC) and power quality (PQ). EMC Filters, RFI Suppression Chokes, Feedthrough Components.

Sunday, June 01, 2008

NO-NC SSR Plastic Box

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.

NO NC SSR Box
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 - Solid State Relays SSR

Temperature Controller 48-96

A 1/8 DIN Indicating Temperature Controller. This is a Analog Controller built around ICL7107. Read more here Temperature Measurement and Control.
48 96 Temperature Controller
This is a 48-96 DIN Temperature Controller, it is mains operated, it is in a Industrial Plastic Housing. It is not meant for very harsh environments. Suitable for Control Panels in Control Rooms. It has a accuracy and linearity of 0.5%. It had options of on-off or time proportional control

Contents

Basic Electronics
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Hobby Circuits
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555 Incredible Chip
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Thermocouples and RTD
Design ADC Interface uC
Thermocouple Amplifier
IA Instrumentation 02
Temperature on DMM
Optical Proximity Switch
Analog Mux - Data Acquisition


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Analog
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TI Semiconductors