24
Instruction Book
IB182942EN July 2018 www.eaton.com
DST-2-VR
+
VR-Series
+
Replacement Circuit Breaker
position and the trip mechanism is released, allowing the breaker
to be operated either electrically or mechanically. If you desire
to electrically open or close the breaker in the test position, the
secondary control block must be re-engaged and the manual motor
cutoff switch turned “on”.
To remove the breaker from the test position to the disconnect
position, the breaker must be tripped if closed, the Interlock Pedal
must be depressed, and the secondary contact block should be
disengaged. When moving out of the test position, a floor close
signal will combine with the trip signal from the Interlock Pedal to
force a trip-free condition. This will cause the charging springs to
discharge leaving the breaker in the open position and the closing
springs discharged. The breaker is in a non-operable state.
Once the breaker is withdrawn past the floor trip activation area, it is
in the disconnected position. The levering handle should be removed
at this point. The breaker is ready to be removed from the cell if
desired.
otte:
N
For Canadian breakers, the interlock plunger will engage in the
disconnect position in the interlock rail on the cell floor.
5.11 OPERATION, INSERTION, AND REMOVAL FOR 5kV
AND 15kV MODELS WITH ROTARY RACKING PROVISIONS
5.11.1 Optrational Positions (Domtstic and somt Canadian
Rotary Racking Vtrsions)
The breaker has three basic operational positions:
(1) Breaker withdrawn from the circuit breaker compartment (cell)
in “disconnect” position.
(2) Breaker in the cell in the “disconnect/test” position.
(3) Breaker in the “connect” position.
otte:
N
Some Canadian versions of the DST-2 have four operational positions,
they have a “withdrawn”, a “disconnect”, a “test”, and a “connect” position.
These versions have one mechanical stop “disconnect” and one for test
unlike all US versions which have a common Disc/Test position.
The “disconnect/test” and “connect” positions can be verified by
the breaker position indicator shown in Figure 5.5.
5.11.2 5kV Instrtion Proctdurt (DST-2-5-VR
+
250, Domtstic
and Canadian Rotary Racking Vtrsion)
a. Verify that the circuit breaker racking system is in the fully
withdrawn position. This is an important step, as breaker
maintenance outside the breaker compartment may have required
that the rotary racking be positioned so that the circuit breaker
could be closed. It must be returned to the fully withdrawn
condition prior to insertion in the circuit breaker compartment.
WARNING
THE BREAKER CAN BE OPERATED WHEN WITHDRAWN FROM THE
CELL, HOWEVER, THE ROTARY RACKING HANDLE MUST BE USED TO
RACK THE BREAKER TO THE CONNECT POSITION, AS SHOWN ON THE
BREAKER POSITION INDICATOR. THE BREAKER MUST BE RACKED TO THE
DISCONNECT/TEST POSITION, AS SHOWN ON THE BREAKER POSITION
INDICATOR, BEFORE INSERTING IT INTO THE CELL.
b. From the withdrawn position, align the center groove of the
breaker wheels with the guide rails of the cell.
c. Check that the closing spring status indicator reads
“DISCHARGED” and that the main contact status indicator reads
“OPEN”. Manually trip, close, and trip the breaker as needed to
obtain this status.
otte:
N
The motor cutoff switch is located on the lower cover where it can be
easily accessed (See Figure Set 3.3). Position the switch to “OFF” before
inserting the breaker into the cell.
d. Push the circuit breaker into the cell until the mechanical stop is
reached; this will be indicated by an audible click. At this point,
the mechanical stop has fallen in the front slot of the guide rail.
In this position, the breaker can be operated. This position can
also be verified by noting that the foot petal moves upward as the
mechanical stop drops. When the interlock foot petal moves up, it
also exposes the racking screw hex head.
otte:
N
For Canadian versions with separate “disconnect” and “test” positions,
it will be necessary to step on the racking interlock petal and push the circuit
breaker to the next mechanical stop. At that mechanical stop, the circuit
breaker is in the “test” position. Provisions in the racking system prevent
the circuit breaker from being pushed beyond this mechanical stop even
when the interlock petal is depressed; any additional movement toward the
“connect” position must be achieved with the rotary racking feature. With the
circuit breaker in the “test” position, item (e.) below can be performed.
e. In the “Disc/Test” position, the breaker can be operated manually
and electrically, thus allowing maintenance tests or checks. To
operate the breaker electrically, the secondary control block must
be engaged at this time. The slider is located on the lower right
hand area of the circuit breaker frame. If electrical testing is
desired at this stage, engage the secondary control block slider
by releasing the slide latch and pushing the slider toward the rear
several inches. Push firmly on the front side of the slider until the
contact block engages with the corresponding cell receptacle.
Return the manual motor cutoff switch to the “on” position. The
spring charging motor will begin to run and charge the closing
spring. The breaker is now in the “test” position, with control
voltage applied, and ready for electrical or manual testing.
NOTICE
ONCE THE SECONDARY DISCONNECT BLOCK IS ENGAGED IN THE “TEST”
POSITION, IT WILL REMAIN CONNECTED THROUGHOUT FURTHER INWARD
MOVEMENT AS THE BREAKER ADVANCES FROM THE “DISC/TEST” TO THE
“CONNECT” POSITION.
THE SPRING CHARGING MOTOR WILL ENERGIZE, IF THE MOTOR CUT-OFF
SWITCH IS IN THE “ON” POSITION (FIGURE SET 3.3), AND CHARGE THE
CLOSING SPRINGS AS THE SECONDARY CONNECTION IS MADE AS LONG
AS CONTROL POWER IS AVAILABLE.
f. From the “Disc/Test” position, the circuit breaker can be advanced
to the “connect” position.
It is NOT ntctssary to sttp on tht
racking inttrlock ptdal whtn tht circuit brtaktr is in this
position.
Place the rotary racking handle onto the rotary racking
hex head. Turn the rotary racking handle clockwise until the
“connect” position is reached and the handle can no longer be
turned, as indicated on the switchgear floor mounted breaker
position indicator, Figure 5.5.
Do not forct tht rotary racking
handlt btyond this point as brtaktr damagt will occur.
Figurt 5.5. Rotary Racking Brtaktr Position Indicator
