The induction motor is equivalent to a rotating transformer. Hence, we can draw the induction motor equivalent circuit with the help of equivalent circuit of the transformer. The basic equivalent circuit of induction motor is shown in Fig. which is very similar to that of a transformer. Here R1 and X1 are the per phase […]
Hi friends, in this article, I am talking about thermal overload relay working principle and its function in a DOL starter. I hope you will find this article informative and helpful. A thermal overload relay works on the heat produced by the excessive overload current. The heat produced by the overload current is utilized to trip
Characteristics of PN junction diode is a graph between the voltage applied across its terminals and the current that flows through it. It is drawn to know the behavior of diode in the electrical circuit. For a typical junction diode, characteristics are shown in Figure. It shows how much current will flow for a particular
Zener diode is a crystal diode having unusual reverse current characteristics which are particularly suitable for voltage regulating purposes. When a reverse voltage applied to a zener diode is increased, a value is reached at which the current increases greatly from its normal reverse value. This voltage is known as zener voltage (Vz) or
Hi friends, in this article, I am going to describe the working principle of rectifier, if you are interested, keep reading. Electric energy is available in homes and industries in the form of alternating voltage. But for the operation of most of the devices in electronic equipment, a DC voltage is required. Therefore almost all
Auto transformer starters are used generally with AC squirrel cage motors having a power rating of more than 20 HP. Motors of these power ratings draw excessive starting current with the use of Star/Delta starter. This may cause excessive strain on the motor and creates an intense voltage dip. This can prove harmful for the motor
A lead-acid battery is the most inexpensive battery and is widely used for commercial purposes. It consists of a number of lead-acid cells connected in series, parallel or series-parallel combination. A lead-acid cell basically contains two plates immersed in electrolyte (dilute sulphuric acid i.e. H2SO4 of specific gravity about 1.28). The positive plate (anode) is
Hi friends, in this article, I am discussing about analog frequency meter working principle and hope you will find it informative and helpful. The action of moving iron analog frequency meter depends on the variation in current drawn by two parallel circuits – one inductive and the other non-inductive – when the frequency changes.
Hi friends, in this article, I am going to describe the significance of vector group of transformer. It is very essential information for parallel operation of transformers and is very interesting as well. Connection of transformer windings can be made in a number of ways. Accordingly, different types of connections have been standardized depending upon
Hi friends, in this article, I am going to discuss the polarity of transformer windings, if you are interested, keep reading. Unlike DC system, there are no fixed positive and negative poles in AC system, and hence, transformers cannot have fixed positive and negative terminals. The relative direction in which primary and secondary windings of a