Electrical (Page 5)

Electrical Engineering, Control Panels and Alternative Energy.

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

Good Earthing Prevents Shocks and Prolongs Appliance Life

Earthing in the olden days was done like this, i have just mixed what i have heard with my common sense and this is what it may be.

Make a deep pit, 4 feet deep, 1/2 feet dia, put long copper rods ( GI pipes or lead pipes were also used). Let the copper rods be driven deeper than the four feet that has been dug. mesh the rods with copper mesh or wire (GI chicken mesh). Fill the pit with all the conductive things which are bio-degradable, non-toxic, non-corrosive and non-soluble. They used coal, charcoal, salt, scrap metals. (now they have a polymer conductive gel). Terminate the copper rods to a thick copper wire run it to your mains box in a way it cannot be cut or broken when gardening etc.

The mains box should be fitted with HRC fuses and MCBs as required, use a ELCB too. The MCB trips when a over current load is drawn, there are both thermal (thermostat technology) and electromagnetic (relay technology) MCBs. The ELCB does not have a earth wire, it trips when the current in the live and neutral paths are unequal. When the difference is say 20mA it trips. This 20mA would have gone thru the ground wire or thru a person giving shock. Also use Over Voltage and Under Voltage Trips if possible, Many equipment fail due to this.

HRC — High Rupture Capacity.
MCB — Miniature Circuit Breaker.
ELCB — Earth Leakage Circuit Breaker.
GI — Galvanized Iron

Also do not forget a lightning rod on the top of the house, whose path to ground is far from the earth pit. Lightning also zaps phones etc. Use Zener barriers for all interfaces between equipment and isolation transformers.

Cable TV wires, phone wires, and mains wires all may get mixed up. During rainy days even a phone line or TV cable may give shock or blow input circuits in equipment. This may be due to mains leakage or lightning.

Before you touch any metal object, cross your fingers, better still buy a long neon tester.

Additional Study

Mains Voltage Stabilizer Circuits

These circuits were drawn for a person in Africa. See the thread here… stabilizer circuit. They were not tested by me, but are quite close to a practical design.

Stabilizer Step up 230V AC 500VA

This circuit is a design i did, not tested by me as yet. It can Stabilize Mains voltage to around +/- 10% . It can be used for both 110V AC or 220V AC inputs with modifications. The Output is 220V AC. There is an overload, under voltage and over voltage trip circuit. With some tweaks and modifications it might work.

Solid-State Stabilizer Step up 110V AC

This circuit is a design concept, not tested by me and i did it just to explain some ideas. The circuit uses opto-coupler MOC3041 of Motorola and the Triac BTA-16-600 of ST as a solid state switch or relay. It also uses the LM324 quad opamp from National Semiconductor which is low power and single supply. As the MOC3041 switches the Triac at zero crossover there is no inter-winding short of transformer on crossover hopefully, the control circuit is designed in such a way that more than one triac will not be turned on at a time, i would like you to give feedback.