1
CIRCUIT BREAKER OPERATION & ADJUSTMENT (AHT
‐
1 & T
‐
12)
Preliminary factory adjustment of the breakers is expected to give
signal light contact con nuity under the following four condi ons:
1.
When the cocking lever is moved beyond the open posi on.
2.
When the cocking lever is moved beyond the closed posi on.
3.
When the trip bar is moved, but before the breaker contacts are
tripped.
4.
When the breaker has tripped completely.
To achieve these condi ons, the posi on of the two signal light
contacts and the calibra ng screw are factory preset. To obtain light
indica on from the reset posi on, the cocking lever must be moved
toward the light tower when the contacts are open. To obtain light
indica on from the closed posi on, the cocking lever must be moved
toward the contacts when the contacts are closed. This allows the
light switch opera on to be checked outside the tank.
Following this preliminary adjustment, the breakers are calibrated
and packaged.
To obtain the same condi ons when the breaker is installed in a
transformer requires the correct amount of free travel at each end of
the opera ng handle mo on.
Obtaining the correct free travel is o en a cut
‐
and
‐
try procedure due
to varia on in the handle loca on, breaker loca on and tank
dimensions. To facilitate this adjustment the following steps may
prove useful.
1. Bolt breaker to support, ghten screws
fi
rmly and back o
ff
the
screw under the trip bar ½ turn.
2. Install the opera ng handle assembly in the tank and ghten
the clamping nut un l the gasket stop bo oms out. Further
ghtening is undesirable.
3. Posi on the opera ng handle to align the yellow arrow with the
“R” on the bearing, allowing about ¼” clearance between the
handle stop and the bearing stop. Posi on breaker in the
cocked posi on with the contacts open.
4. Screw the connec ng rod (link arm) in to the cocking lever un l
the holes in the rod and opera ng arm mate. Insert a co er pin
in the holes, hold co er pin in place and move the opera ng
handle to check for the following opera ons:
a.
Close and open the breaker.
b. Close breaker, trip light contact manually (avoid tripping
main breaker contacts). Reset light by moving opera ng
handles to the “L” posi on.
c. Trip breaker contacts and try rese ng the breaker. A
properly adjusted breaker will have approximately ¼” of
travel le between the handle and bearing stops. If
breaker fails to operate properly, adjust connec ng rod
un l the above opera ng condi ons are obtained.
FOR MORE INFORMATION VISIT
ermco
‐
eci.com
ERMCO COMPONENTS, INC | 1607 Industrial Road | Greeneville, TN 37745
5. Install
co er pin permanently; avoid binding between rod and
lever.
6.
Install signal light in tank wall; ghten clamping nut only enough
to compress the gasket. Avoid over
‐
ghtening.
7. Posi on calibra on control mechanism (overload lever) on the
breaker at the “normal” posi on. Insert the preformed end
control wire into the breaker overload lever and thread the
control cable (sheath) into the support on the breaker and lock
the connec on by pinching the support around the cable
sheath.
8. Posi on the calibra on control mechanism (overload lever) on
the breaker in the “normal” posi on. Hold the control assembly
lever on the opera ng handle bearing in the “normal” posi on.
Thread the control cable through the hole in the cable support
and lock the connec on by pinching the support around the
cable sheath. Twist the control wire into and around the
emergency overload control lever as show below.
9.
Connect signal light winding to terminal on the breaker.
10. Connect signal light winding to the signal light.
11. For breakers without emergency overload and signal light, the
following procedure is recommended to make the breaker
assembly adjustment in the transformer tank:
a. Place breaker in the cocked posi on with the contacts
open.
b. Adjust threaded connec ng rod (link arm) so that the
yellow arrow on the opera ng handle is aligned with the
“O” on the bearing.
c. Check breaker for proper reset and close opera ons.
Adjust connec ng rod (link arm) to achieve proper
opera on, if required.
ECI
A1
‐
15
11/04
A1
‐
16
10
‐
21
