IB
6.1.12.1-1C
8
ABB
attempted closure will only discharge the closing
springs. With MO breakers, the closing handle action
will not engage the closing springs.
Maintenance Handle (EO)
Shown in Figure 1b, the maintenance handle is used
for charging the closing springs of motor-driven
mechanisms when control power is not available. It is
also used for adjusting the simultaneous contact
make during a slow-close operation.
Motor Disconnect Switch (EO)
Used only on electrically charged mechanisms, the
motor disconnect switch (MDS) is wired in series with
the spring charging motor circuit. The switch serves
two functions:
1. Stops the normal sequence of recharging closing
springs following a breaker opening (without de-
energizing the control power source).
2. Isolates the motor from the control wiring when
withstand-voltage testing the control wiring (which
is tested at a higher voltage than the motor itself).
Remember to leave the switch ON after returning a
breaker to service.
Nameplate
The nameplate identifies the rated performance limits
of the circuit breaker as certified per design. Do not
exceed these limits. The nameplate also lists the
circuit breaker model type, frame size, and serial
number. Provide the serial number when contacting
ABB for information.
Racking Mechanism
Utilize a racking handle, as shown in Figure 1b, to
operate the racking mechanism of draw-out circuit
breakers. The racking mechanism moves a draw-out
type circuit breaker between any of three positions:
CONNECTED, TEST, or DISCONNECTED. Position
is indicated by a decal in two places: the left upper
cradle arm (open cubicle door) and on the escutcheon
box right-side (closed cubicle door). The racking
shutter is interlocked with the position of the breaker
contacts to deny handle insertion unless the breaker
is open. Additionally, the circuit breaker is trip-free
between racking positions.
Stored Energy Indicator (EO)
This mechanical flag indicates the stored energy
condition of the closing springs. The two states of the
flag are marked "SPRINGS CHARGED" and
"SPRINGS DISCHARGED."
Trip Buttons
All breakers have a mechanical push button trip for
opening the breaker locally. A second optional trip
button electrically operates the shunt trip for locally
opening the breaker.