The main requirements of the insulating materials used for power apparatus are: 1. High insulation resistance 2. High dielectric strength 3. Good mechanical properties i.e tenacity and elasticity 4. It should not be affected by chemicals around it 5. It should be non-hygroscopic because the dielectric strength of any material
Year: 2014
GROUNDING Grounding is one of the most important aspects of an electrical distribution system but often the least understood. Your Electrical Code sets out the legal requirements in your jurisdiction for safety standards in electrical installations. For instance, the Code may specify requirements in the following areas: (a) The protection
1) OLD GUIDELINES ARE NOT THE BEST GUIDELINES Guidelines like the Computer Business Equipment Manufacturers Association Curve (CBEMA, now called the ITIC Curve) and the Federal Information Processing Standards Pub94 (FIPS Pub94) are still frequently cited as being modern power quality guidelines. The ITIC curve is a generic guideline for
The three major factors contributing to the problems associated with power quality are: USE OF SENSITIVE ELECTRONIC LOADS The electric utility system is designed to provide reliable, efficient, bulk power that is suitable for the very large majority of electrical equipment. However, devices like computers and digital controllers have been
The Institute of Electrical and Electronic Engineers (IEEE) defines power quality as: “The concept of powering and grounding electronic equipment in a manner that is suitable to the operation of that equipment and compatible with the premise wiring system and other connected equipment.” Making sure that power and equipment are
The term power quality (PQ) is generally applied to a wide variety of electromagnetic phenomena occurring within a power system network. The ability of the power systems to deliver undistorted voltage, current and frequency signals is termed as quality of power supply. Unexpected variation of the voltage or current from
VOLTAGE DIP is a reduction in the RMS voltage in the range of 0.1 to 0.9 pu (retained) for duration greater than hall a mains cycle and less than 1 minute, Often referred to as a ‘sag’, Caused by faults, increased load demand and transitional events such as large motor
1. What is the “end of useful life”? The IEEE defines “end of useful life” for a UPS battery as being the point when it can no longer supply 80 percent of its rated capacity in ampere-hours. When your battery reaches 80 percent of its rated capacity, the aging process
Quantifying the combined effect of the four factors that affect battery life discussed in the previous page is difficult. You need a way to determine when a battery is near the end of its useful life so you can replace it while it still works, before the critical load is
In most UPSs, you don’t use just one cell at a time. They’re normally grouped together serially to form higher voltages, or in parallel to form higher currents. In a serial arrangement, the voltages add up. In a parallel arrangement, the currents add up. However, batteries are not quite as
