EKF VA-99M EKF - Design and Operating Principle

2
1 DESCRIPTION
The molded case circuit breaker VA-99M EKF is designed for infrequent routine
close/open operations and overload/short-circuit protection to be used in
electrical installations for residential and civil engineering, industrial facilities,
power substations, electrical distribution points, panel electrical equipment at
rated operating voltage up to 400 V AC at 50 Hz under currents from 16 to 1600
Amps.
The molded case circuit breakers comply with the requirements
of IEC 60947-2:2016.
2 DESIGN AND OPERATING PRINCIPLE
The molded case circuit breaker (MCCB) VA-99M is a monoblock consisting of
a base and a cover with a window for the operating handle and a window for
pressing the push-button "TEST" to test the tripping mechanism.
The base is made of thermal-resistant, ame-retardant ABS plastic and is a
supporting structure for connecting terminals, xed power contacts with an
arc fault protection system, a control mechanism with a system of movable
contacts, electromagnetic and thermal trip units. The bimetallic strip executes
thermal protection. The trip units have factory settings and are non-adjustable.
The housing cover is made of thermal-resistant ABS plastic, covers the entire
mechanism and protects personnel against electric shock when operating the
circuit breaker.
The control mechanism is based on the break lever principle and has a strong
return spring to ensure quick tripping. The arc fault protection system consists
of equidistant steel plates that direct the gas ow into an outlet window enclosed
by a perforated wall, which ensures optimum discharge and dissipation.
However, when the the molded case circuit breakers are installed in conned
space of the switchgear, arc products can be discharged if the overcurrent
protection is triggered.
The motor mechanism has manual mechanical and electrical remote control
to ensure trouble-free operation, even in case of power disconnection. The
front panel features an indicator of the motor mechanism status and a manual/
automatic switch.
WARNING! When the switch is in the "automatic" position, the extended rotary
handle is disabled. The wiring diagram is located on the left side of the motor
mechanism.
The MCCB VA-99M power supply can be connected from both xed and movable