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IB131006EN
Table 5.2 Circuit Breaker Timing
circuit breaker is levered to the CONNECTED position.
Event
Closing Time
(From Initiation of Close
Signal to Contact Make)
Opening Time
(Initiation of Trip Signal
to Contact Break)
Reclosing Time
(Initiation of Trip Signal
to Contact Make)
When the CS/C contact is made, the SR closes the
circuit breaker. If the CS/C contact is maintained after
the circuit breaker closes, the Y relay is picked up. The
Y/a contact seals in Y until CS/C is opened. The Y/b
contact opens the SR circuit, so that even though the
circuit breaker would subsequently open, it could not be
reclosed before CS/C was released and remade. This is
the anti-pump function.
5-4.1
TIMING
The opening and closing times for the circuit breakers
vary depending upon the control voltage and the power
rating. Typical values for VCP-W outdoor breaker
elements are shown in Table 5.2.
5-4.2
SECONDARY DISCONNECTS
The circuit breaker control wiring is arranged to connect
a standard 25 point male plug with a corresponding
switchgear compartment mounted female plug. The
circuit breaker plug is fixed mounted on the left side
under the bottom pan of the mechanism (Figure 4-4).
The female plug is mounted in the compartment on a
movable carriage (Figure 4-2).
The secondary disconnects engage automatically as the
circuit breaker is levered into the CONNECTED position,
and disengage as the circuit breaker is withdrawn from
the CONNECTED position. To engage the secondary
contacts while the circuit breaker is in the TEST.
E f f ec t iv e 0 7/ 2 0 1 7
Courtesy of NationalSwitchgear.com
been made while the
Milliseconds (maximum)
45-60
30-45
140-165
position, raise the handle and pull the carriage all the
way towards the front (Figure 4-5). This will latch the
contacts. To disengage the contacts, simple push the
carriage to the rear.
5-4.3 UNDERVOLTAGE TRIP DEVICE
The under voltage trip device for VCP-W circuit breakers
is an electromechanical device that operates to open the
circuit breaker at 30% or less of the voltage rating of the
trip coil. The device does not open the circuit breaker at
values above 60% of the voltage rating of its trip coil. It
may operate, however, to open the circuit breaker when
the voltage across the trip coil is greater than 30%, but
less than 60% of the voltage rating of its trip coil. The
circuit breaker can be closed as long as the voltage to
the trip coil is maintained at 85% or above the rated level.
The under voltage trip device is available only as an
instantaneous type with rated voltages of 48VDC,
125VDC, 250VDC, 120VAC and 240VAC.
For a basic understanding of the operation of the under-
voltage trip device refer to the specific items identified in
Figure 5-6 and the following operation description.
With the circuit breaker closed and sufficient voltage
1.
on the Under voltage Trip Device coil, the moving
clapper (1) is held to the stationary yoke (2) by the
magnetic force produced by the coil (3) against the
extension springs (4) pulling the moving clapper apart
from the yoke.
The moving clapper is connected to the mechanism
2.
Trip D Shaft Lever (5) by a slotted link (6).
When the voltage to the Under voltage Trip Coil goes
3.
down as described earlier, the extension springs force
overcomes the reduced magnetic force and pulls the
moving clapper up. The slotted link in turn upsets the
Trip D Shaft and the circuit breaker trips open.
As the circuit breaker opens, the reset lever (8)
4.
connected to the pole shaft lever (7) operates to reset
the moving clapper. As long as the circuit breaker
remains open, the reset lever holds down the moving
clapper to the yoke.
When the circuit breaker closes, the reset lever
5.
moves away from the moving clapper. If the Under-
voltage Trip Device coil has at least 85% of the rated
voltage applied, the moving clapper is held to the
yoke by the magnetic force, even though the reset
lever has moved up.
Page 39
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