Categories: Machine

Load Characteristics Of D.C. Compound Generator

The characteristics depends on whether generator is cumulatively compound or differentially compound generator. In cumulatively compound, ?2r = ?2r + ?2r. As load current increases,  Iincreases hence  Ise  also increases producing more flux. But as  Iincreases, the various voltage drops and armature reaction drop also increases. Hence there is drop in the terminal voltage.

If drop in Vdue to increasing  Iis more dominating than increase in Vdue to increase in flux then generator is called under compounded and its characteristics is dropping in nature, as shown in the Fig. 1.

If drop in Vdue to armature reaction and other drops is much less than increase in Vdue to increase in flux then generator is called over compound and its characteristics is rising in nature, as shown in the Fig. 1. If the effects of the two are such that on full load current Vis same as no load induced e.m.f. i.e. the effects are neutralizing each other on full then then generator is called flat compounded or level compound. Its characteristics is shown in the Fig. 1.

In differentially compound, ?= ?sh ~ ?se.. The net flux is difference between the two. As Iincreases, ?sh  is almost constant but ?se increases rapidly. Hence the resultant flux ?reduces. There is drop due to armature resistance, series field resistance, armature reaction due to which terminal voltage drops further. Thus we get the characteristics of such differentially compound generator as shown in the Fig. 1.

admin

Share
Published by
admin

Recent Posts

Standby Generators and Custom Commercial Generators for Sale

Humankind has become extremely dependent on electricity, without it we can’t run the household, keep…

4 years ago

Electrical Machine Interview Question And Answer

[1] Define the term synchronous speed [Dec-2003] For synchronous machines there exists a fixed relationship…

7 years ago

Transformer Interview Questions With Answer

We shared a lot of interview questions on electrical machines, power system and power electronics. Today we…

7 years ago

What Is Diesel Power Station

DIESEL POWER STATION A generating station in which diesel engine is used as the prime…

7 years ago

Synchronous Generator Interview Questions

Q:Why syn. generators are used for the production of electricity? A:synchronous machines have capability to…

7 years ago

Hydro Power Station

Hydro-electric Power Station A generating station which utilises the potential energy of water at a…

7 years ago