Posts

Showing posts from April, 2018

How to Repair a PDA Charger at Home: A Step-by-Step Guide

Image
How to Repair a PDA Charger at Home: A Step-by-Step Guide PDA chargers (and mobile chargers in general) can be a little fragile. They usually consist of an AC adapter, a thin wire, and a set of small prongs that fit into your phone’s charging port. Because of their delicate build, a charger can easily get damaged — whether it’s a frayed cable from everyday wear, a bent connector pin from incorrect insertion, or even a pet chewing through the wire. Instead of buying a new charger right away, you can often repair a damaged one at home with a few basic tools. Below are two common charger issues and step-by-step instructions to fix them. Case 1: Bent Charger Prongs What you’ll need: Magnifying glass, tweezers Steps: Inspect the prongs: Use a magnifying glass to carefully check which prongs are bent at the end of the charger (opposite the AC wall plug). Straighten the prongs: Grip each bent prong gently with tweezers and pull it back into alignment. Repeat for all damaged pr...

Sensorless Vector control; Sensorless Vector control Vs V/f control

Image
Variable Frequency Drive (VFD) Sensorless Control: Working, Features & Comparison Variable Frequency Drives (VFDs) are widely used to control the speed and torque of three-phase induction motors. In addition to the basic V/f (voltage-to-frequency) characteristic , modern drives offer sensorless control features that optimize motor performance without external feedback devices like encoders. 🔹 Key Features of Sensorless Control in VFDs 1. Slip Compensation What is Slip? Slip is the load-dependent difference between the motor’s reference speed and actual speed . How it Works: The VFD measures output current and adjusts the stator frequency to compensate for slip. Activation: Automatically enabled during guided commissioning. Can be manually activated by entering the stator resistance value (from the motor datasheet). Important Parameters: Amplification → Defines how much speed correction is applied. Max. Slip Ramp → Limits frequency change per se...

Life of Electrical cables

Image
Service-Age of Medium Voltage Power Cables: Life, Testing, and Maintenance Introduction Power cables are the lifelines of any electrical system, ensuring reliable energy transfer to equipment and utilities. While many types of cables exist in the market, their performance and life expectancy depend heavily on installation practices, operating conditions, and maintenance. Typically, electrical cables last 20–30 years under optimal conditions. However, environmental factors such as open-air exposure, trenches, conduits, cable trays, load cycles, and frequent start-stop operations can significantly influence cable health. In the United States, the aging MV (medium-voltage) cable infrastructure has become a pressing issue. Many utilities and industries rely on networks that are decades old, raising the question: How do we accurately assess the condition of service-aged power cables? What Is a Service-Age of Cables? A cable is considered service-aged after five years of ...

Types of Bushings and Voltage ratings

Image
Bushings in Transmission Systems: Types, Classification & Applications Bushings are one of the most critical components in transmission and distribution systems . Their primary role is to provide insulation between energized conductors and grounded parts , ensuring safe current transfer through transformer tanks, circuit breakers, switchgear, and other high-voltage equipment. A failure in bushings can lead to catastrophic equipment damage, fire hazards, or extended outages. Hence, understanding their classification, design, and application is vital for electrical engineers and maintenance teams. Classification of Bushings Bushings can be classified into three main categories: 1.       Based on Insulating Material Used 2.       Based on Construction Type 3.       Based on Internal Insulation 1. Classification by Insulating Material Bushings are often categorized based on the type...

Electric Vehicle chargers and running cost of electric vehicles

Image
Electrical vehicles seems to becoming reality as there is increased focus on reducing pollution and reducing dependency on petroleum products. But there are many challenges while going with electric vehicles such as time required for charging the vehicles and space required for parking the vehicles and also higher cost of electric vehicles in comparison to other vehicles. There is also challenge for long driving as while driving long charging of vehicles will be required after few intervals, which required considerable time for charging again. There is lot of infrastructure and electricity is required to cater all these problems. Cost of driving electric vehicle is very low in comparison to petroleum products. There are few terms you must know before going through in details:- On Board Charging:- There are chargers which are factory fitted and are known as on board chargers and there are 2 types of charging devices for the same:- (i)       ...