experiment2 ratio polarity

8/12/2019 EXPERIMENT2 Ratio Polarity

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ASCT/EEE/LAB/BEE-02

(Ratio & Polarity Test)

EXPERIMENT NO. - 02

AIM: To perform the ratio &polarity test on -!Transformer

IN"TR#MENT" RE$#IRE%:

S. No. Instruments Type Range Qty (nos.)

1) Transformer 1-/1!APrimary -2"0#/$0%

Se' 0-11$!-2"0!01

2) !oltmeter * 0-"00 ! 02

") !oltmeter * 0-"00! 01

TEOR':T+is e,eriment is 'arrie. ot '+e' t+e olarity of transformer in.ins T+is is se

for arallel 'onne'tion of to transformers

Transformer is a stati' .e#i'e3 +i'+ is se to transfer ele'tri' enery from one

ele'tri' 'ir'it (rimary) to anot+er ele'tri' 'ir'it (se'on.ary) #ia maneti' 'ir'it

('ore) at .ifferent #oltae & 'ir'it le#els T+e to ele'tri' 'ir'its ie rimary

in.in an. se'on.ary in.in +a#in .ifferent nm4er of trns .etermines tye of

transformer5 ste- an. ste-.on

(A) Ratio Test:T+e in.'e. emf er +ase in rimary an. se'on.ary in.ins of a transformer is

i#en 4y6

emf in rimary3 E( ).))f !Nemf in se'on.ary E2( ).))f !N2

7e 'an .efine transformation ratio as6

2

1

1

2

1

2

I

I

V

V

E

EK ===

(B) Polarity Test:

Ea'+ of terminals of rimary as ell as se'on.ary in.in of a transformer is

alternati#ely ositi#e an. neati#e it+ rese't to ea'+ ot+er *t is essential to no

Pae 1 of "


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ASCT/EEE/LAB/BEE-02


t+e relati#e olarities at any instant of t+e rimary an. se'on.ary terminal for main

'orre't 'onne'tions3 if t+e transformers are to 4e 'onne'te. in arallel or to 4e se. in

"-'t

7+en #iee. from t+e rimary si.e t+e terminals are mare. A1& A2 8o terminal

A1 is 'onne'te. to one en. of t+e se'on.ary in.in an. a #oltmeter is 'onne'te.

4eteen A2an. ot+er en. of t+e se'on.ary in.in

7+en #oltmeter rea.s t+e .ifferen'e (!1- !2)3 t+e transformer is sai. to ossess a

s4tra'ti#e olarity an. +en #oltmeter rea.s (!19!2)3 t+e transformer +as a..iti#e

olarity

S4tra'ti#e olarity means3 same olarity terminals are 'onne'te. A..iti#e olarity

means alternati#e ositi#e an. neati#e terminals are 'onne'te.

PRO*E%#RE:(Ratio Test)1 Conne't t+e 'ir'it as er fi6 1 an. set- atotransformer to ero osition

2 Sit'+ on t+e 1-: AC sly & a.;st atotransformer ntil a sita4le

(4elo rate.) #oltae

" Re'or. t+e #oltae !1a'ross t+e rimary & !2a'ross se'on.ary


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ASCT/EEE/LAB/BEE-02


> Sit'+ off t+e sly

PRO*E%#RE:(Polarity test: sutra!tive polarity)1 Conne't t+e 'ir'it as er fi6 22 & set- atotransformer to ero osition

2 Sit'+ on t+e 1- : AC sly & #ary atotransformer ste 4y ste

" Re'or. for ea'+ ste t+e #oltae !13 !23 an. !"

experiment2 ratio polarity

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