ABB AMVAC Technical Manual page 4

The magnetic actuator,
encapsulated vacuum interrupter
pole assemblies, electronic
controller, capacitors, and push
button/capacitor discharge
assembly are the key components
for this next generation product.
The magnetic actuator has a
magnetic frame assembly, two
identical operating coils, two rare
earth magnets, and a single moving
armature. Instead of mechanical
assemblies for armature position
sensing, proximity sensors detect
armature position for the
electronic controller. The rare earth
magnets are especially encapsulated
to eliminate the corrosion normally
associated with this type of
magnet. Evaluation confirms that
these permanent magnets will
retain 99% of their flux density for
over 100 years.
Similar evaluations find that the
capacitors used for stored energy
have a lifetime up to 20 years.
These special capacitors charge in
as little as seven seconds after
control power is available and are
periodically "topped off" by the
electronic controller as needed.
Covers over the capacitor terminals
prevent accidental contact. The
capacitors are discharged by a
unique discharge assembly when
the circuit breaker is moved to the
"Disconnect" position and the
racking truck handles are moved
inward to unlock the circuit break-
er from the breaker compartment.
The AMVAC circuit breaker is
designed to provide many years of
trouble free service for the end
user.
4
AMVAC
Summary of benefits:
• Simple mechanical operation
• Fewer than 10 moving parts
• Manual opening capability
• High reliability
Manual opening mechanism
Magnetic actuator
Electronic controller
Auxiliary contacts
Electrical energy storage
Sensor for switching position
detection