Quantcast WORKING ON CIRCUIT BREAKERS

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
2-39 The TIME DELAY RATINGS of circuit breakers are INSTANTANEOUS, SHORT TIME DELAY, and LONG TIME DELAY. SELECTIVE TRIPPING is used to cause the circuit breaker closest to the faulty circuit to trip, isolating the faulty circuit without affecting other nonfaulty circuits. This is accomplished by using an instantaneous circuit breaker close to the load, a short time delay circuit breaker at the next junction, and a long time delay circuit breaker at the main junction box. The FACTORS used to select a circuit breaker are the power requirements of the circuit and the physical space available. When WORKING ON CIRCUIT BREAKERS, the following items should be done BEFORE working on the circuit breaker: Check the applicable technical manual, obtain the approval of the electrical or engineering officer (for shipboard circuit breakers), remove power from the circuit breaker, and tag the switch that removes power from the circuit breaker. The following items should be checked and discrepancies corrected when working on circuit breakers: Check the operating mechanism for smooth operation, check the contacts for pitting, check the terminals for tightness and corrosion, check the mounting hardware for tightness and wear, check all components for wear, and check the entire circuit breaker for cleanliness. ANSWERS TO QUESTIONS Q1. THROUGH Q43. A1.   To protect people and circuits from possible hazardous conditions. A2.   A direct short, excessive current, and excessive heat. A3.   A condition in which some point in the circuit where full system voltage is present comes in contact with the ground or return side of the circuit. A4.   A condition that is not a direct short but in which circuit current increases beyond the designed current carrying ability of the circuit. A5.   A condition in which the heat in or around the circuit increases to a higher than normal level


Electrical News
Integre Brings x1 HyperLink DSP to FPGA
Integre's IP core allows a user-defined system to communicate with...
eetimes.com
SanDisk Goes For Big Data Flash Market
InfiniFlash storage platform puts company in competition with customers and...
eetimes.com
March 28 is Arduino Day -- Break Out the Party Hats!
On 3/28/2015, the folks at SparkFun are offering up to...
eetimes.com
Four Steps to Field-Oriented Control -- The Final Two
Concluding Dave's series on implementing field-oriented control, he looks at...
eetimes.com
Why We Disagree with the IEEE's Patent Policy
The IEEE's new patent policy could slash royalty revenues and...
eetimes.com
Linux Seeks Security, Unity
Linux needs greater security, unity and interoperability to meet its...
eetimes.com
Friday Quiz: EE 101, Part 3
In this third installment from "Electrical Engineering 101," we look...
eetimes.com
Robotic Bacteria Senses Humidity
A bacterial spore studded with graphene quantum dots makes the...
eetimes.com
Teensy-Weensy GPAK4 Mixed Signal FPGAs
For embedded designers who aren't familiar with FPGAs, Silego's teensy-weensy...
eetimes.com
Vehicle Reliability Is Up, Especially in Powertrain
Some cars are more reliable than others, but even the...
eetimes.com
Convince Me Why I Should Care About VR
When I go to a conference and see bobble-headed enthusiasts...
eetimes.com
OFC: Transceiver Module Spec Prevents Mismatching
A keyed CDFP optical module prevents cables from being plugged...
eetimes.com
Single-Chip FPGA-Based Embedded Vision & Fusion Analytics Solutions
The idea here is to perform 'processing on the edge'...
eetimes.com
Micron, Intel Flash 3D NAND
Micron and Intel have co-developed a 3-D flash NAND chip...
eetimes.com
ESC Minneapolis 2015 Sneak Peek! Baking Pis in Africa
Do you want to hear tall tales of rafting the...
eetimes.com
The Art Of Electronics 3rd Edition
25 years in the making, the bible of electronics is...
eevblog.com
Patent Suits Have Global Impacts
Companies found guilty of patent infringement, even those under an...
eetimes.com
Nanolaser Enables On-Chip Photonics
\Researchers at the University of Washington and Stanford has created...
eetimes.com
DARPA Robotics Challenge Gears Up For Finale
The latest highlights from DARPA's years-long robotics competition show us...
eetimes.com
Core Independent MCUs Come to Power Management
Using redundant sets of key power management functions, Microchip has...
eetimes.com
 


Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +