dc tachogenerator

8/19/2019 DC Tachogenerator

1/22

AEI 305.29 to 30 1

DEPARTMENT OF TECHNICAL EDUCATION

ANDHRA PRADESH

Name of the staff :Sri N.Khaja meeranDesignation :Lectrer

!ranch :AEIE

Institte :S.".#.$ "o%t &o'(technic)Krnoo'

*ear+Semester :III Semester S,ject :#rocess Instrmentation-I

S,ject coe :AEI-305

/o&ic :Dis&'acement an &osition measrement

S,-/o&ic :A an D tacho generator

Dration :100 ins

/eaching Ais :##/) Animations) #hotogra&hs.


2/22

AEI 305.29 to 30 2

&on the com&'etion of this to&ic (o i'' ,e a,'e

to 4no a,ot

A an D tacho generators.

• #rinci&'e

• &eration

• Its a%antages an isa%antages .

Objectives


3/22

AEI 305.29 to 30 3

#rinci&'e

It o&erates on the &rinci&'e that..

/he re'ati%e motion ,eteen a magnetic fie' an a

conctor res'ts the %o'tage generation in that conctor.


4/22

AEI 305.29 to 30 6

•

7or measrement of ang'ar %e'ocit( tachogeneratorsare se

• /here are to t(&es of tacho generators

• 18 D. tacho generator

• 28 A. tacho generator


5/22

AEI 305.29 to 30 5

D /acho "enerator

7ig 1


6/22

AEI 305.29 to 30

onstrction

• An armatre is rotating t(&e an this magnet is a

fie t(&e.

• /he armatre is co&'e to the machine hose

%e'ocit( is to ,e measre.

• It consists of commtator an ,rshes is connecte

to the armatre

• t&t is connecte to a o%ing oi' ;8 t(&e

%o'tmeter


7/22

AEI 305.29 to 30 <

&eration

• =hen the armatre is stationar( there is no

re'ati%e motion ,eteen the magnetic fie' an

the armatre ining.

•

>ence the ot&t %o'tage is ?E$.


8/22

AEI 305.29 to 30 @

• As the armatre s&ee increases the re'ati%e motion

a'so increases.

• /he ot&t %o'tage is ince in the armatre ining.

• /he magnite of this %o'tage is &ro&ortiona' to the

s&ee of the armatre.

• A commtator an ,rshes are connecte in the

armatre to gi%e the D ot&t %o'tage.


9/22

AEI 305.29 to 30 9

• /he &o'arit( of ot&t %o'tage inicates the

irection of rotation

• /his ot&t %o'tage is measre ith the he'& of

mo%ing coi' %o'tmeter ca'i,rate in terms of s&ee.

•/he re'ationshi& ,eteen the D ot&t %o'tage

an ang'ar %e'ocit( is gi%en ,(


10/22

AEI 305.29 to 30 10

=here

ω = ang'ar %e'ocit(

e0 D ot&t %o'tageN& No. of &o'es

Nc No. of conctors in armatre

B& f' &er &o'eN&& &ara''e' &aths ,eteen &ositi%e an negati%e

,rshes.

−φ

= ×& c & @

0

&&

N Ne 10 %o'ts

90N

−= ×φ

0 && @

& c &

e 0N10 r&m

N N


11/22

AEI 305.29 to 30 11

/he main a%antage of this meter is the irection of

rotation is inicate ,( the &o'arit( of the ot&t

%o'tage.

Advantages


12/22

AEI 305.29 to 30 12

Disadvantage

• /he commtator an ,rshes reCire

&erioic maintenance.

• /he ot&t %o'tage is non-'inear


13/22

AEI 305.29 to 30 13

AC Tac!" gene#at"#

• /he 7ig.2 shos the A. tacho generator.


14/22

AEI 305.29 to 30 16

C"nst#$cti"n

• It consists of

• #ermanent magnet ;rotor8

• oi' ;stator8

• $ectifier ,rige

• o%ing oi' ;8 %o'tmeter


15/22

AEI 305.29 to 30 15

O%e#ati"n

• =hen the magnet rotates in a stationar( coi' ) an A

%o'tage is generate

• /he am&'ite an the freCenc( of this %o'tage are ,oth

&ro&ortiona' to the s&ee of rotation

• /hs either am&'ite or freCenc( of ince %o'tage

ma( ,e se as a measre of rotationa' s&ee

• /he ot&t %o'tage of ac tacho generator is rectifie an

is measre ith %o'tmeter


16/22

AEI 305.29 to 30 1

Advantages

• aintenance free e to the a,sence of ,rshes an

commtators


17/22

AEI 305.29 to 30 1<

Disadvantages

• Large nm,er of &o'es are reCire

• $eCires high in&t im&enence is&'a( e%ices


18/22

AEI 305.29 to 30 1@

=e ha%e iscsse a,ot

• /he &rinci&'e an o&eration of D tacho generator

• Its a%antages an isa%antages.

• /he &rinci&'e an o&eration of A tacho generator

•Its a%antages an isa%antages.

S$&&a#'


19/22

AEI 305.29 to 30 19

1.D tacho generators are se for measrement of

;A8 Linear %e'ocit(

;!8 Ang'ar %e'ocit(

;8 Linear is&'acement

;D8 Ang'ar is&'acement

($i)


20/22

AEI 305.29 to 30 20

2.D tacho generators con%erts

;A8 $otation into e'ectrica' signa'

;!8 Dis&'acement into e'ectrica' signa'

;8 /em&eratre into e'ectrica' signa'

;D8 #ressre into e'ectrica' signa'


21/22

AEI 305.29 to 30 21

3.Ang'ar %e'ocit( measrement is carrie ot ,( sing a

;A8 /aco generators

;!8 o%ing coi' t(&e transcer

;8 o%ing iron t(&e transcer

;D8 #ieo e'ectric transcer


22/22

AEI 305.29 to 30 22

18 E&'ain the o&eration of D tacho generator ith a neat

iagram.

28 List the a%antages an isa%antages of D /acho

generator.

38 E&'ain the o&eration of A tacho generator ith a neat

iagram

68 List the a%antages an isa%antages of A /acho

generator.

F#e*$ent+' As,ed ($esti"ns

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