GE NGV29A User manual

0
Instructions
GK-49896C
SENSITIVE
GROUND
RELAY
(Formerly
0178AS900)
TYPE
NGV29A
These
instructions
do
not
purport
to
cover all
details
or variations
in equipment
nor
to
provide
for every
possible
contingency
to
be
met in connection
with installation,
ope,tion
or
maintenance
Should
further information
be
desi,d
or should
part
icular
problems
arise which
ae
not
covecd sufficiently
for the
purchaser’s
purposes, the
matter
should
be
referred
to
the
General Electric
Company.
To the
extent
required
the products
described
herein
meet
applicable
ANSI,
IEEE and
NEMA
standards; but
no
such
assurance
is given with
respect
to
local
codes
and ordinances
because they
veiy greatly.

CEK—49896
CONTENTS
Description
3
Application
3
Ratings
3
Operating
Principles
3
Characteristics
4
Burden
4
Construction
4
Receiving.
Handling
and
Storage 4
Electrical
Tests
5
Drawout
Relays,
Ceneral
5
Power
Requirements,
Ceneral
5
Acceptance
Tests
5
Seal—in
Circuit
Test
5
Periodic
Checks and
Routine
Maintenance
6
Contact
Cleaning
6
Servicing
6
Renewal
Parts
6
2

CEK-49896
SENSITIVE
GROUND
RELAY
TYPE
NGV29A
(Formerly
0178A8900)
DESCRIPTION
The
Type
NOV
relay
covered
by
these
instructions
is
a
sensitive
DC
relay
for
ground
detection.
It
consists
of
two
telephone—type
relays,
and
a
sensitive
polarized
relay,
with
associated
diodes
and
resistors,
mounted
in
a
size
Si
single—end
drawout
case.
APPLICATION
The
12NGV29A(—)A
relay,
is
designed
to
provide
sensitive
ground
protection
for
DC
buses.
Typical
external
connections
for
such
an
application
are
shown
in
Figure
6.
The
relay
will
indicate
whether the
ground
is
on
the
positive
or
negative
bus,
depending
upon
which
of
the
polarized unit contacts
close.
Ground
sensitivity
for
the
available
voltage
ratings
is
listed
in the
section
on
CRARACTERISTICS.
RATINGS
The
Model
12NGVZ9A(—)A
relay
is
available
in
four
voltage
ratings:
24,
48, 125
or
250
VDC.
The relays
are
continuously
rated
at
these
voltages.
The
L
and
R
telephone
relay
contacts
are continuously
rated
at
3
amperes
and
are
capable
of
momentarily
carrying
30
amperes
at
250
VDC for
tripping
duty,
but should
be
interrupted
by
some
other
suitable
means
if
the
interrupting
capability
shown in
Table
I
is
exceeded.
TABLE
I
CONTACT
INTERRUPTING
ABILITY
Volts
Interruption
Capability
(Amps)
Inductive**
24DC
1.0
48DC
1.0
125DC
0.5
250DC
0.25
**
Inductance
of
average
trip
coil.
The non—inductive
interrupting
ratings
for
repetitive
protective
duty
are approximately
2
1/2
times the ratings
shown
in
the
table.
OPERATING
PRINCIPLES
The
Model
12NGV29A(—)A
relay
consists
of
two
telephone
relays,
a
sensitive
polarized
relay
and
two
diode
boards
contained
in
an
Si
single—ended
drawout
case.
A
typical
telephone
relay
is
shown
in
Figure
3.
The
sensitive
relay
will detect
a
current
leakage
to
ground
from
either
the
(+)
or
the
(—)
DC
bus
and
operate
to
close
its
contact,
which
will
energize
either
the
L
or
3

cgK -49896
R
relay,
depending
on
the
direction
of
ground—car’-ent
flow.
The
T
unit
pickup
indicates
a
(—)
DC—to—ground leakage,
and
the
R
unit
pickup
will
indicate
a
(÷)
DC-
to—ground
leakage.
Tn
either
case the
L
or
R output
wiLl
close
a
contact
to
sound
an
alarm
or
trip
a
breaker.
CHARACTERISTICS
The
Model
I2NGV29A(—)A
relay
consists
of a
sensitive
DC
relay
for
use as
ground—
current
detector.
The
two
telephone
relays
(L and
R)
are the
output
relays,
and
when
energized
will
close
a
contact
that
can
be
used
for
tripping
or
alarm.
A
seal—
in
circuit
is available by connecting
studs
3 and
8
to stud
7, if
desired.
The
relay
has a
maximum
resistance—to—ground
sensitivity
as
listed
below.
DC Voltage Rating
Naximum
Resistance—to—Ground
Sensitivity
(Ohms)
24
1.25
K
48
5
K
125
15
K
L
250
30
K
BURD€N
The
burden
imposed
by
the relay
on
the
DC
bus
under
normal
conditions
will
be
the
current
drawn
by
Ri
and R2
in
series,
divided
into
the
DC
voltage.
Refer
to
the
chart
out
the
internal
connection
diagram
of
Figure
5
for
the resistor
and
component
resistance
values.
CONSTRUCTION
The relay
components
are
mounted
in
a
cradle
assembly
that
is
latched
into
a drawout
case
when
the relay
is in
operation
but
can
be
easily
removed
when
desired.
To
do
this,
the
relay
is
first
disconnected
by
removing
the
connection
plug
that
completes
the
electrical
connections
between
the case
block
and
the
cradle
block.
To
test
the
relay
in
its
case,
this
connection
block
can
be
replaced
by a
test
plug.
The
relay
case
is suitable
for
either
semi—flush
or surface
mounting
on
all
panels
up to
two
(2)
inches
thick,
and
appropriate
hardware
is available.
However,
panel
thickness
must
be
indicated
on the
relay
order
to
be
sure
that
proper
hardware
will
be
included.
For outline
arid
drilling
dimensions,
see
Figure
4.
Every
circuit
in
the
drawout
case
has
an
auxiliary
brush,
as shown
in
Figure
7, to
provide
adequate
overlap
when
the
connecting
plug
is
withdrawn
or
inserted.
For
the
electrical
circuits
and
the
external—connection
diagrams
see
Figures
5
and
6.
RECEIVING,
HANDLING
AND
STORAGE
These
relays,
when
not included
as
part
of
a control
panel,
will
be
shipped in
cartons
designed
to
protect
them
against
damage.
Immediately
upon
receipt
of
a
relay,
examine
it
for
any
damage
sustained
in
transit.
If
injury
or
damage
resulting
from
rough
handling
is
evident,
fle
a
damage
claim
at
once
with
the
transportation
company
and
promptly
notify
the
nearest
General
Electric
Sales
Office.
4

CEK-49896
Reasonable
care
should
be
exercised
in
unpacking
the
relay
in
order
that none
of
the
parts
irjurcd
nor
th
adjustments
disturbed.
If
the
relays
are
not
to
he
installed
itmuediately,
they
should
be
stored
in
their
original
cartons
in a
place
that
is
free
from
moisture,
dust and
metallic
chips.
Foreign
matter
collected
on
the
outside
of
the
case may
find
its
way
inside
when
the
cover
is
removed,
and
cause
trouble
in
the
operation
of
the
relay.
ELECTRICAL
TESTS
DRAWOUT
RELAYS,
GENERAL
Since
all drawout
relays
in
service
operate
in
their cases,
it
is
recommended
that
they
be
tested
in
their
cases
or
an
equivalent
steel case.
In
this
way any
magnetic
effects
of
the
enclosure
will. he
accurately
duplicated
during
testing.
A
relay
may
be
tested
without
removing
it
from
the
panel
by
using
a
12XLA13A
test
plug.
This
plug
makes
connections
only
with
the
relay.
Of
course,
the
12XLAl2A
test plug
may
also
be
used.
Although
this test
plug
allows
greater
testing
flexibility,
it
also
requires
the
exercise
of
greater
care,
since
connections are
made to
both
the relay
and
the
external
circuitry.
POWER
REQUIREMENTS,
GENERAL
Relays
requiring
DC
control
power
should
be
tested
using DC
and
not
full—wave
rectified
power.
Unless
the
rectified
supply
is
well filtered,
many
relays
will
not
operate
properly,
due
to
the
dips in
the
rectified
power. Zener
diodes, for
example,
can
turn
off
during
these
dips.
As
a
general
rule,
the
DC
source
should
not
contain
more
than
5%
ripple.
ACCEPTANCE
TESTS
Apply
60%
of
rated
voltage
(see
Table
Ifl
to
studs
5(+)
and 6(—).
Connect
a
test
resistor
across
studs
4
and
6
and
the
left
telephone
relay
should
pick up.
Connect
a
test
resistor
across
studs
4
and
5
and
the
right telephone
relay
should pick
up.
TABLE II
Rated
Bus
Voltage
60%
Rated
Bus
Voltage
Test Resistor
Ohms
24
VDC
14.4
VDC
500K
48
VDC
28.8
VDC
2K
125
VOC
75
VDC
5K
250
VOC
140
VDC
10K
Note that
the
L
or
R
relay
will drop
out
whenever
the
test
resistor
is
removed from
the
studs
mentioned
above.
SEAL—IN
CIRCUIT
TEST
Short
studs
3
and
8
to
stud
7
and
repeat
the
above
tests,
and note
that the
L
or
R
relay
does
not
drop
out
when the
test
resistor
is
removed
from the
studs
mentioned.
In
order to
drop
out
L
or
K,
the
DC
supply
voltage
must
be removed.
For
a
more
accurate
test
of
the
relay,
refer to
the
section
on
SERVICING.
5

GEK
-4
9
89 6
PERIODIC
CHECKS
AND
ROUTINE
MAINTENANCE
In
view
of
the
vital
role
of
protective
relays in
the
operation of
a
power
system,
it
is
important
that
a
periodic test
program
be
followed.
It
is
recognized
that
the
interval between
periodic
checks
will
vary
depending upon
environment,
type of
relay
and
the
user’s
experience
with
periodic
testing.
Until
the
user
has
accumulated
enough
experience
to
select
the
test
interval
best
suited
to
his
individual
requirements,
it
is
suggested that
the
points
listed
under ELECTRICAL
TESTS
and
ACCEPTANCE
TESTS
be
checked
at
an
interval
of
from
one
to
two
years.
CONTACT CLEANING
For
cleaning relay
contacts,
a
flexible
burnishing
tool
should
be
used.
This
consists
of
a
flexible
strip
of
metal with
an
etched—roughened surface,
resembling
in
effect
a
superfine
file.
The
polishing
action
is
so
delicate that
rio
scratches
are
left,
yet
it
will
clean off
any
corrosion
thoroughly
and
rapidly.
The
flexibility
of
the
tool ensures
the
cleaning
of the
actual
points
of
contact.
Do
not
use
knives,
files,
abrasive paper
or
cloth
of
any
kind
to
clean
relay
contacts.
SERVICING
Connect an
adjustable
rheostat
of
the
value
listed
in
Table
III
to
stud
4
and
stud
6.
with
the
rheostat set
for
maximum
ohms.
Apply
rated voltage to
studs
5(+)
and
6(-);
neither
the
L
nor
the
R
relay
should
operate.
Reduce
the
resistance
of the
rheostat
until
the
left
“L”
relay
picks
up.
This
should occur
as
listed
below
under
“Sensitivity”
in
Table
III.
(Measure
the
resistance
remaining on
the
rheostat.)
Put
the
rheostat
(set
at
maximum
resistance)
to
studs
4
and
5,
and
reduce
the
resistance;
the
right
CR)
relay
should
pick
up.
Measure
the
resistance
of the
rheostat;
this
should
be
between
the
values
listed
in
Table
III.
TABLE
III
Related
Maximum
Test Rheostat
Sensitivity
for
Rated
Bus
Voltage
Resistance
to Ground
in
Ohms
Telephone
Relay
to
Operate
Pickup
24VDC
1.25K 5K
1.75—
3K
48
VDC
5 K
15
K
7
-
14
K
125
VDC
15
K
50
K
17
—
35
K
250
VDC
30
K
75
K
34
— 70
K
RENEWAL
PARTS
Sufficient
quantities of
renewal
parts
should
be
kept
in
stock
for
the
prompt
replacement
of
any
that
are
worn,
broken
or
damaged.
When
ordering
renewal parts,
address
the
nearest
Sales
Office
of
the
General
Electric
Company.
Specify
the
name
of
the
part
wanted,
quantity required,
and
complete
nameplate data,
including
the
serial number,
of the
relay.
6

1
R2—
GEK—4 9896
Figure
1
(8043268) NGV29A
Relay. Front
View, Out
of
Case
7

GEK—4
9896
TERM
INAL
Figure 2
(8043269)
‘DIODE
8OARD
-——TERM1NAL
1
NCV29A
Relay,
Rear
View,
Out of
Case
8

CEK—49896
FRMF
[_
OFERTING
RM
\ ARMTLIRE
R
ES
D
Li
4
SCFEw
L__
LOCKNJT
POLE P
FoE
Figure 3
(8012106) Typical
Telephone Relay
Used
in the
NGV29A Relay
.F
LEND
SOiL
OPERAT:
tO,
STCP
9

GK
-49896
9,125
232MM
EL
ASS
1
125
29MM
PANEL
LOCATION
SEMI—FLUSH
STUB
NUMBER
I NE
97531
00000
00000
10
862
BACK
VIEf
4
281
5 c 5 cccJ
1 468
Ô
37MM
-500
12MM
(TY T
CAL)
PANEL
]JRILLN1
FOR
SURFACE
MDUN
ING
FRONT
VIEW
TYPICAL
DIM.
INCHES
MM
____
3.0
76Mh
‘
VIEW
SHOWING
ASSEMBLY
OF HARDWARE
FOR
SURFACE
MTG. ON
STEEL PANFLS
*
Figure
4
(K-6209271
[81)
Outline
and
Panel-Drilling
for the
0178A8900
Relay
_____
6
625
_____
168MM
•
-C
(2) 5/16—18
STUDS
FOR
SURFACE
MTG.
8
375
212MM
4)
10—32
X
3/8
MTG.
SCREWS
1 0—32
STUBS
1/4
DRILL
4 HOLES
6MM
157MM
5/8
DRILL
2
HOLES
--i--
CUTIJUT
111MM
CUTOUT
MAY
REPLACE
DRILLE!)
HOLES
1. 156
29MM
218
5MM
843
72MM
5.
687
14
4MM
PANEL
DRILLING
FOR
SEMI-FLUSH
MOUNTING
FRONT
VIEW
•3/4
DR.LL
10
HOLES
19MM
5/1618
STUD
10