Electrical Engineering Articles



D.C 3 Point Starter

It can also be called a three-point starter. Its structure is shown in Figure. To start the motor, the handle is moved from off position to the first contact position. The total obstacle is in the armature circuit, the field connection is connected directly to the supply through a volt coil. Comes in as soon as the speed of the motor increases in the same way as the archete back emf emits and decreases in the value of current Now the handle is moved to the second step. Again this…

DC Circuit Rules

Ohm’s law I = V / R Joule’s law P = V · I = I 2 · R = V 2 / R Series circuit rules VT = V1 + V2 + V3 + … IT = I1 = I2 = I3 = … RT = R1 + R2 + R3 + … 1/CT = 1/C1 + 1/C2 + 1/C3 + … LT = L1 + L2 + L3 + … Parallel circuit rules VT = V1 = V2 = V3 = … IT = I1 + I2 + I3 + … 1/RT = 1/R1 + 1/R2 + 1/R3 + … CT = C1 + C2 + C3 + … 1/LT = 1/L1 + 1/L2 + 1/L3 + … Voltage division V1 = VT ⋅ R1 / (R1+R2+R3+…) Current division I1 = IT ⋅ (R2+R3+…) / (R1+R2+R3+…) Kirchhoff’s voltage law (KVL) The sum of voltage drops at a current loop is zero: ∑ Vi = 0 Kirchhoff’s current law (KCL) The junction between several circuit elements is called a node. The sum of the currents values at…

Ohm’s Law Formula

The relationship between Voltage, Current and Resistance in any DC electrical circuit was firstly discovered by the German physicist Georg Ohm. Georg Ohm found that, at a constant temperature, the electrical current flowing through a fixed linear resistance is directly proportional to the voltage applied to it, and also inversely proportional to the resistance. This relationship between the Voltage, Current and Resistance forms the basis of Ohm’s Law and is shown below. Ohm’s Law Relationship By knowing any two values of the Voltage, Current or Resistance quantities we can use Ohm’s Law to find…

4 Point DC Motor Starter

The formation of this starter has been shown in the figure. We have seen that DC motors cannot be combined with direct supply because the motor is damaged. To avoid this, the starter is used. We use the DC stator And we will now know about the DC 4 point starter. Its composition has been shown as shown in the figure. We can see that one end of the DC solution is given in overloaded relay, and given in the handle. It is arranged in accordance with the order of…

Types of DC Motors, Forms, and Uses

DC motors are of 3 types as follows D.C.Series Motor: Which is attached to the field with a field coil armature in DC motors, it is called a series motor. Its field coil is made of a low-angle thick wire. Such motors are very high work in the starting. When changes in armament currents are changed in such motors, flux changes also. In other words, the load decreases with speed as much as it grows. Similarly, when the load decreases, the reduction in currents And increase in the back emf.…

Hopkinson’s Test or Regenerative Test On DC Motor

Hopkinson’s test or regenerative test is a full load test and it requires two identical machines which are coupled to each other.In this test two identical d.c. machines mechanically coupled to each other and simultaneously tested.One is operated as generator another one as the motor, hence we can find the efficiency of two dc machines simultaneously.So output power of dc machines is going to be wasted.The mechanical output of motor given to generator through the shaft to shaft mechanical coupling.And generator’s electrical power supplied to run the motor, where losses will be supplied by the external power source. If there are no…

Purpose of Interpole in DC Machine

For understanding the role of Interpoles, we need to understand the effect of armature reaction in the DC Machine. The effect of armature mmf on the main field flux is to distort the main field flux and to reduce the net main field flux. The figure below, shows the effect of armature mmf on the main field flux. It is quite clear from the above figure that the flux at the location of Carbon Brush i.e. A, B and A are not zero and therefore an EMF will be induced…