A Website on Maintenance of Electrical Systems

Draw-Out Circuit Breaker A trip unit is the part of a circuit breaker that automatically opens the contacts of the circuit breaker in the event of a short circuit, ground fault, or thermal overload. There are two types of trip units; the thermal-magnetic trip unit, and the electronic trip unit. A thermal-magnetic trip unit  has moving parts. It consists of a bimetallic thermal device that opens the circuit breaker with a delay depending on the magnitude of overcurrent. It also consists of a system where magnetic forces proportional to the current flowing through the circuit breaker are used to actuate the breaker. Simply put, in the event of a short circuit, high current flows and a strong magnetic field is created. This magnetic field is used to actuate the trip mechanism.   An electronic trip unit  is a programmable device that measures and times the current flowing through a circuit breaker and initiates a trip signal when appropriate. There are 6 common current protection

HVAC refers to a complete system of Heating, Ventilation, and Air conditioning. It could refer to the Air conditioner in your room or the large system used in High Rise buildings. HVAC equipment could perform Heating and/or Cooling. Using the same refrigeration cycle it could act as a heat pump for heating or an air conditioner for cooling. How it works. Every refrigeration system has 4 key components that make it work. These are the evaporator, the condenser, the compressor, and the expansion valve. The job of these four main components is explained in the refrigeration cycle. Key things to understand before we continue. §   Water boils at 100 °C only at atmospheric pressure, if the pressure is reduced, water would boil at a lower temperature. Boiling point and condensation point temperatures are not fixed because they vary with pressure. §   A refrigerant absorbs heat from the environment when it evaporates. §   A refrigerant boils (evaporates ) between -20 °C to

The Amp Hour rating of a battery simply describes the battery capacity. The Ah rating shows the amount of energy(charge) that the battery can store. Common examples include 65Ah, 75Ah, 90Ah, 100Ah, or 200Ah. The Ampere hour (Ah) rating tells us the amount of current a fully charged battery would deliver for a certain period of time. In essence, a battery rated for 100Ah should be able to supply 100 Amps for 1 hour or 1 Amp for 100 hours. Similarly, a 65Ah battery should deliver 1 Amp for 65Hrs or 65Amps for 1hr. 200Ah should deliver 1 Amp for 200Hrs 100Ah battery should deliver 1 Amp for 100 hours, 100Ah battery should deliver 2 Amps for 50 hours, 100Ah battery should 3 Amps for 33 hours etc. It would be nice if this equation held true all the way up to 100 amps for 1 hour, but there are some limits on the maximum amount of current you can draw from a battery without destroying the battery. Batteries however have a rating called C-rate. This rating informs us of the maximum curren