Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
3-16 depends mainly on three things: (1) the number of conductors in series per winding, (2) the speed (alternator rpm) at which the magnetic field cuts the winding, and (3) the strength of the magnetic field. Any of these three factors could be used to control the amount of voltage induced in the alternator windings. The number of windings, of course, is fixed when the alternator is manufactured. Also, if the output frequency is required to be of a constant value, then the speed of the rotating field must be held constant. This prevents the use of the alternator rpm as a means of controlling the voltage output. Thus, the only practical method for obtaining voltage control is to control the strength of the rotating magnetic field. The strength of this electromagnetic field may be varied by changing the amount of current flowing through the field coil. This is accomplished by varying the amount of voltage applied across the field cod. Q20.   How is output voltage controlled in practical alternators? PARALLEL OPERATION OF ALTERNATORS Alternators are connected in parallel to (1) increase the output capacity of a system beyond that of a single unit, (2) serve as additional reserve power for expected demands, or (3) permit shutting down one machine and cutting in a standby machine without interrupting power distribution. When alternators are of sufficient size, and are operating at different frequencies and terminal voltages, severe damage may result if they are suddenly connected to each other through a common bus. To avoid this, the machines must be synchronized as closely as possible before connecting them together. This may be accomplished by connecting one generator to the bus (referred to as bus generator), and then synchronizing the other (incoming generator) to it before closing the incoming generator’s main power contactor. The generators are synchronized when the following conditions are set: 1. Equal terminal voltages. This is obtained by adjustment of the incoming generator’s field strength. 2. Equal frequency. This is obtained by adjustment of the incoming generator’s prime-mover speed. 3. Phase voltages in proper phase relation. The procedure for synchronizing generators is not discussed in this chapter. At this point, it is enough for you to know that the above must be accomplished to prevent damage to the machines. Q21.   What generator characteristics must be considered when alternators are synchronized for parallel operation? SUMMARY This chapter has presented an introduction to the subject of alternators. You have studied the characteristics and applications of different types. The following information provides a summary of the chapter for your review. MAGNETIC INDUCTION is the process of inducing an emf in a coil whenever the coil is placed in a magnetic field and motion exists between the coil and the magnetic lines of flux. This is true if either the coil or the magnetic field moves, as long as the coil is caused to cut across magnetic flux lines.

Electrical News
Ultralow noise & Ultrahigh PSRR
The LT(R)3042 is a high performance low dropout linear regulator...
EEVblog #776 – World’s Smallest Digital Dosimeter
A look at the Ultra Micron, the world’s smallest digital...
EEVblog #775 – Mailbag
Dave opens his mail. A potpourri of items this week....
Terahertz Optical Transistors Beat Silicon
Purdue University researchers demonstrate CMOS-compatible all-optical transistor capable of 4-THz...
Carmakers Raise Stakes in Map Battle vs. Google
BMW, Audi and Mercedes -- to purchase Nokia's HERE map...
NI Week: Videos From Opening Day
NI Week opened today with a two-hour exhibit opening. Here's...
What Will Make Wearable Technology Take Off?
Wearable technology will take off when people can wear it,...
Expansion of Information Technology Agreement Big Deal for Semiconductor Industry
The recent ITA deal is a huge shot in the...
OmniVision Shareholders Approve Seagull Takeover
The shareholders of CMOS image sensor vendor OmniVision Technologies Inc....
Indian Fab Project Hires Former GloFo Exec
Indian foundry fab will be located near Indore in Madhya...
NASA Preps Venus ICs
NASA is sending a mission to Venus, where the surface...
Will The World Coalesce Around USB Type C?
USB Type C is still too new for any market...
Agile Design for Hardware, Part III
In the final installment of a three-part series, two Berkeley...
EMI Antennas Come in Many Shapes & Sizes
EMI antennas are needed for compliance and precompliance emissions and...
The ACM/IEEE International Conference on Information Processing in Sensor Networks...
Silicon Valley's Longest-Serving CEO Beginning New Chapter
With the impending close of Microchip's $840 million acquisition of...
EEVblog #774 – Low Battery Discharge Testing Part 1
Dave shows how to do discharge testing on AAA and...
Perambulating & Texting -- Dazed & Confused
It seems that walking while texting is becoming endemic; so...
IBM Takes A Second Turn at PCM Drift
Another approach taken by IBM and Macronix to address phase...
The Next Big Thing Is The Continuum
What will come next for us? Internet of Everything, wearables,...

Privacy Statement - Copyright Information. - Contact Us

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

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