Category Archives: Electrical

Sensitivity of PMMC Voltmeter

The current sensitivity of voltmeter of moving coil type like PMMC voltmeter is defined as the deflection per unit current in the coil. If Ɵ be the angular deflecting of needle of voltmeter for current I through the moving coil, then sensitivity of voltmeter is given as S = Ɵ / I You might think…

3-Phase Hall Sensor BLDC Driver Using Z32F128 MCU

This MultiMotor Series application note investigates the closed- and open-loop control of a 3-phase brushless direct current (BLDC) motor using a Z32F128 ARM Cortex M3 MCU. Zilog’s ZNEO32! Family of microcontrollers is designed specifically for motor control applications and, with this MultiMotor Series, features an on-chip integrated array of application-specific analog and digital modules using…

Ward-Leonard Method of Speed Control

As discussed in the previous post “Speed Control of DC Motor”, speed of DC Motor can be controlled by varying the terminal voltage Vt of the DC Motor. Ward-Leonard Method is the application of this principle where the terminal voltage Vt of DC Motor is varied to control the speed of DC Motor. Ward-Leonard Method…

Speed Control of DC Motor by Varying Field Flux

In previous post “Speed Control of DC Motor” we discussed the method of speed control of DC Motor by Armature Circuit Resistance Control Method. In this post we will discuss the method of speed control of DC Motor by varying the Field Flux which is known as Field Weakening Method. By Field Weakening Method of…

Measurement of Three Phase Power by Two Wattmeters Method

There are three methods which are used for the measurement of three phase power in three phase circuits. The three methods are: Three Wattmeters Method Two Wattmeters Method Single Wattmeter Method In this post, we will discuss on the Three Phase Power Measurement using Two Wattmeters. Two Wattmeters Method: In this method, a three phase…

Principles of Power Conversion

The world today is dependent on a variety of electronic devices which is essential in our day-to-day activities and tasks whether be it for communication, instrumentation, control systems, or other miscellaneous use. No matter what type of electronic device, be it a consumer-based product such as computers, cell phones, game systems and the like or…

Why DC Series Motor should not be Started at No Load?

In this post we will discuss about the Speed Current Characteristics of DC Series Motor. After going through this post ask yourself the answer of the question “Why DC Motor should not be Started at No Load?” I am sure that you will be able to answer. In DC Series Motor the field winding remain…

Voltage Build up in DC Shunt Generator

In this post we will discuss how Voltage is Build up in DC Shunt generator at No Load. Consider a DC Shunt Generator at no load as shown in figure below. The switch in the field circuit is supposed open and the armature of DC Shunt Generator is driven at rated speed. Because of presence…

Speed Control of DC Motor

DC Motor speed control means to have full control on the speed of DC Motor. The variation in speed of DC Motor because of variation in load is not the speed control. Therefore intentional variation in speed of DC Motor is called Speed Control. As we know that for a DC Motor having armature resistance…

Brushless Excitation System

 Brushless Excitation System is a technology for providing the field current to the Synchronous Generator without using Slip Ring and Carbon Brushes. As this method of Excitation i.e. Brushless Excitation System do not use Carbon Brushes, therefore the losses because of contact resistance of carbon brushes is eliminated. Also, in case of initial start up…