Cutler-Hammer - Eaton Canada

B1-8
Medium-Voltage Distribution Equipment
Metal-Clad Switchgear – Drawout Vacuum Breakers (VCP-W)
Application and Technical Data
Control Equipment
Circuit Breaker Control
The VCP-W circuit breaker has a motor charged
spring type stored energy closing mechanism.
Closing the breaker charges accelerating
springs. Protective relays or the control switch
will energize a shunt trip coil to release the
accelerating springs and open the breaker. This
requires a reliable source of control power for
the breaker to function as a protective device.
For ac control, a capacitor trip device is used
with each circuit breaker shunt trip to ensure
that energy will be available for tripping during
fault conditions. A control power transformer
is required on the source side of each
incoming line breaker. Closing bus tie or bus
sectionalizing breakers will require automatic
transfer of control power. This control power
transformer may also supply other ac auxiliary
power requirements for the switchgear.
Signal: Initiation of
Initiation of
Close Signal
Trip Signal
VCP-W
Circuit Breaker
Main Contacts
Breaker Aux.
Switch
"a" Contact
Rated
Control
Voltage
48 Vdc
125 Vdc
250 Vdc
120 Vac
240 Vac
9.0
4.0
2.0
4.0
2.0
C
Closing Time
∆t = 45-60 ms
6
6
6
6
6
∆t ±3 ms
16
7
4
6
3
200
80
40
T
Opening Time
∆t = 30-45 ms
Table 11: Control Power Transformers, 1 Phase, 60 Hertz➀➁
Taps Secondary
+7
Volts
1 ⁄2% Rated -71 ⁄2%
2580
2400
2220
240/120
4470
4160
3850
240/120
5160
4800
4400
240/120
7740
7200
6680
240/120
9030
8400
7770
240/120
13405
12470
11535
240/120
14190
13200
12210
240/120
14835
13800
12765
240/120
24725
23000
21275
240/120
37088
34500
31913
240/120
38-56
100-140
200-280
104-127
208-254
Cutler-Hammer
∆t ±3 ms
28-56
70-140
140-280
104-127
208-254
kVA kV
Class
5, 10, 15
5, 10, 15
5, 10, 15
5, 10, 15
5, 10, 15
5, 10, 15
5, 10, 15
5, 10, 15
5, 10, 15
15, 25
5
5
5
15
15
15
15
15
27
38➂
.035
.035
.035
.035
.035
May 2001
Dc control would require a dc control battery,
Open
battery charger and an ac auxiliary power
source for the battery charger. The battery provides
a very reliable dc control source, since it
is isolated from the ac power system by the
battery charger. However, the battery will require
periodic routine maintenance and battery
capacity is reduced by low ambient temperature.
Breaker Aux.
Switch
"b" Contact
"b" Breaks 6 ms
Before "a" Makes
∆t –6 ms
to –3 ms
"a" Breaks 7 ms
Before "b" Makes
Closed
∆t +10 ms
to +4 ms Open
Any economic comparison of ac and dc con-
Table 9: Auxiliary Switch Contacts Interrupting Capacities
trol for switchgear should consider that the ac Type Auxiliary Switch Continuous Control Circuit Voltage
capacitor trip is a static device with negligible
maintenance and long life, while the dc bat-
Current
Amperes
120 Ac 240 Ac 48 Dc 125 Dc 250 Dc
tery will require maintenance and replace-
Non-inductive circuit interrupting capacity in amperes
ment at some time in the future.
Breaker Auxiliary Switch 20
15
10
16
10
5
TOC
20
15
10
16
10
5
Relays
MOC Auxiliary Switch 20
15
10
16
10
5
Microprocessor-based or solid-state relays
Inductive circuit interrupting capacity in amperes
would generally require dc power or reliable
uninterruptible ac supply for their logic circuits.
Breaker Auxiliary Switch
TOC
20
20
15
15
10
10
16
16
10
10
5
5
Auxiliary Switches
MOC Auxiliary Switch 20
15
10
16
10
5
Optional circuit breaker and cell auxiliary
switches are available where needed for
interlocking or control of auxiliary devices.
Typical applications and operation are
described in Tables 8 and 9.
Table 10: VCP-W Breaker Stored Energy Mechanism Control Power Requirements
Spring Charge Motor UV Trip Voltage Range Ind.
Run Time Close or Trip
mA (Max.)
Close Trip
Light
Amperes Seconds Amperes
Amperes
Auxiliary switch contacts from the circuit
breaker mechanism are limited in number by
the breaker control requirements usually to
one “a” and two “b” contacts for ac control or
two “a” and two “b” contacts for dc control.
When additional auxiliary contacts are needed,
the optional auxiliary relay or mechanism
operated cell (MOC) switch is used. Two
types of MOC switches are available:
a. operates with breaker in connected
position only.
b. operates with breaker in connected
➀ Line-to-line connection only available.
➁ Refer to Cutler-Hammer for other voltages and
kVA ratings.
➂ 150 kV BIL.
position and test position.
The optional truck operated cell (TOC) switch
operates when the circuit breaker is levered
into or out of the operating position.
MOC and TOC switch contacts are not field
convertible from “a” to “b” or “b” to “a”. Up
to 3 MOC switches, each with 5a and 4b contacts,
and 1 TOC with 4a and 5b contacts can
Table 8: Breaker Auxiliary Switch Operating Times
be provided in each breaker compartment.
Auxiliary switch contacts are primarily used
to provide interlocking in control circuits,
switch indicating lights, auxiliary relays or
other small loads. Suitability for switching
remote auxiliary devices, such as motor heaters
or solenoids, may be checked with the
interrupting capacity listed in Table 9. Where
higher interrupting capacities are required,
Closed
Open
Closed