GEK-49848A
The
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eft sea 1- i n un i t o perates i n conjuncti on wi th the ti me-overcurrent un i t
contacts and i s l a bel ed 11 T11•
I ts co i l i s i n ser i es and i ts contacts i n pa ral l el
wi th the ma i n contacts o f the ti me-overcurrent un i t so that when the ma i n contacts
cl ose, the seal - i n un i t wi l l p i ck up and seal i n aroun d the ma i n contact.
The ri ght seal - i n un i t, l a bel ed 11I 11 o perates i n conjun c t i o n wi th the
i ns tantaneous overcurrent un i t.
I ts co i l i s i n ser i es wi th the i ns tantaneous un i t
contact and a contact of the d i recti onal un i t, and i ts contacts are connected to
seal - i n around these two contacts when the un i t o perates; on rel ays equi pped wi th
an auxi l i ary tel e phone rel ay, the contacts al so sea l - i n aroun d a contact of the
tel e phone rel ay.
Both seal - i n un i ts are equi pped wi th targets wh i ch are ra i sed i nto v i ew when
the un i t o perates.
These targets l atch and rema i n exposed un t i l manua l l y rel eased by means of the
button project i n g bel ow the l ower- l eft corner of the cover.
INSTANTANEOUS OVERCURRENT UN IT {D I RECT I ONALLY
The i nsta ntaneous overcurrent un i t i s s i m i l ar i n constructi on to the
d i rect i onal un i t descri bed a bo ve, d i ffer i ng onl y i n co i l turns and connect i ons. The
four corner coi l s con s i st of two wi n d i n gs, an i nner w i n d i n g con s i s t i n g of a l a rge
number of turns of fi ne wi re, and an outer wi nd i ng ha v i n g a few turn s of heavy wi re.
The outer wi n d i ngs of the corner coi l s are connected ei ther i n seri es or i n paral l el
wi th the s i de co i l s by t a p l i nks prov i ded o n the rel ay; these seri es or pa ral l el
combi nati ons are connected i n seri es wi th the o pera t i n g co i l o f the TOC un i t.
The
i nner w i ndi n gs of the corner co i l s are al l connected i n seri es, and i n turn are
connected i n seri es wi th a ca pa c i tor and a contact of the di recti onal un i t.
Thi s
c i rcui t thus control s the torque of the i ns tantaneous overcurrent un i t. When the
d i recti on a 1 un i t contacts are o pen, the i n stantaneous overcurrent un i t wi l l devel o p
n o torque.
When the d i recti onal un i t contacts are cl osed, the i ns tan taneous
overcurrent un i t wi l l devel o p torque i n pro porti on to the square of the current.
The i ns tantan eous overcurrent un i t devel o ps o perati n g torque i n a di rect i on
o p pos i te to that of the d i recti onal un i t. Thi s makes the rel ay l es s susce pti bl e to
the effects of s hock.
INSTANTANEOUS UNIT (NON-DIRECTIONALLY
Thi s
roc
un i t i s a smal l hi n ged a rmature type i ns tantaneous el ement and i s
mounted on the ri ght s i de o f the TOC un i t. The
roc
el ement o perates over a 25-to
one total ran ge o btai ned by us i n g a ta p ped co i l wh i ch has a fi ve- to-one l ow ran ge
and a fi ve- to-one h i gh range; thi s combi nat i on prov i des the 25- to-one total ran ge.
When the current reaches a predetermi ned val ue, the i nstantaneous el ement operates
cl os i n g i ts contact ci rcui t and ra i s i n g i ts target i nto v i ew. The target l atches i n
the exposed pos i ti on unt i l i t i s rel eased. The same button that rel eases the ta rget
seal - i n un i t al so rel eases the target of the i ns tantaneous un i t.
TELEPHONE RELAY AUX I L IARY UN IT
The auxi l i ary tel e phone rel ay un i t, when used, i s mounted be hi nd the
di recti onal un i t.
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