Option L34 (Output-Side Circuit Breaker) - Siemens SINAMICS G130 Engineering Manual

Description of Options
Engineering Information
Withdrawable version of a SENTRON WL circuit
breaker
9.7

Option L34 (Output-side circuit breaker)

This option is available for SINAMICS S120 Cabinet Modules (only for air-cooled units, but not for liquid-cooled
units).
The option L34 (Output-side circuit breaker) has been designed for drives with permanent-magnet synchronous
motors to allow the motor to be disconnected from the inverter, whereby the disconnection can take place under full
load.
Rotating, permanent-magnet synchronous motors produce a voltage at their motor terminals which is proportional to
speed. The motor terminal voltage is thus also present at the inverter output terminals, on the DC link and on the
components connected to it.
To allow disconnection on faults or for servicing, an optional output-side circuit breaker is available for Motor Modules
in Chassis format in the SINAMICS S120 Cabinet Modules range.
Option L34 is required in the following applications with permanent-magnet three-phase synchronous machines:
·
Drives with a high moment of inertia, which require a long time for comming to standstill and which generate
a voltage at the motor terminals during this time.
·
Mechanically-coupled auxiliary drives, which can be mechanically driven by the main drive.
·
Maintenance and repair at the converter, when the machine cannot, for example, be brought to a standstill
by means of mechanical braking.
·
Operation in the field weakening range in combination with a suitable limitation of the DC link voltage in the
converter (e.g. a braking unit) which, in the event of a fault tripping of the inverter, effectively limits
the DC link voltage until the circuit breaker is opened. For more detailed information, refer to the section
"Drives with permanent-magnet three-phase synchronous motors" of the chapter "General Information about
Drive Dimensioning".
Option L34 comprises a circuit breaker which is housed in a separate cabinet to the right of the Motor Module. This
additional cabinet is 400 mm wide for frame sizes FX and GX, and 600 mm wide for frame sizes HX and JX. The
breaker is controlled via the inverter and a Terminal Module which, like the breaker itself, is an integral component of
option L34 and thus shipped completely wired. Commissioning is supported by BICO logic circuits based on free
function blocks. External remote OFF switches can be connected to the breaker.
Circuit breakers are subject to limited duty cycles. To extend the service life of the output-side breakers, these are not
opened when the inverter receives a normal "OFF" command (OFF1, OFF2, OFF3). The breaker is tripped as
standard by the "Fault" state on the Motor Module, by failure of the auxiliary supply voltage for option L34, or by
actuation of the "OPEN" button on the breaker or an equivalent external control mechanism. When the "OPEN"
button directly on the breaker is actuated, the Motor Module is also switched off (pulse inhibit).
SINAMICS Engineering Manual – November 2015
504/528
Ó Siemens AG
In addition to the standard functions / options, the withdrawable
version of the SENTRON WL circuit breaker features the following
supplementary functions:
• Position indicator on the breaker front panel
• Captive crank-handle for moving the withdrawable breaker
• Slide-in frame with guide rails for easy breaker handling
• Locking capability to prevent movement of breaker
• Withdrawable breaker cannot be moved when the breaker is
closed
• Rated current coding between slide-in frame and withdrawable
breaker to prevent insertion of incorrect breaker rating.