Fuji Electric Frenic lift, Справочное руководство

Страница: 200 / 254

2.3 Overview of Function Code
C
hap.
2
FUN
CT
IO
N
C
O
D
E
S
Motor Speed
(mm/s)
0
L117
RBRK
BRKS
ON
ON
L119
RUN command
(FWD or REV)
Alarm
ON
EN1&EN2
L108
Figure 4. Inverter locked by
rbA
(case 2).
L120 Short circuit control (Control mode)
L121 Short circuit control (Check time)
While motor is stopped motor brakes are closed. If for any reason motor brakes are opened
externally (during installation or maintenance for example) motor will turn free in to the loads
direction. In case of PMSM, because it has no gearbox, the speed of the lift moving due to gravity
can reach quite high speeds. On the other hand, when motor phases are short-circuited, it generates a
torque which makes rotating speed slower. Because of this, market trend is to short circuit motor
phases when lift is in standstill. Motor phases are short circuited to have an additional safety.
On the other hand, market trend is moving to contactorless solutions. Without contactors the
installation (wiring) is easier, there is less maintenance, and acoustic noise is reduced. FRENIC-Lift
(LM2A) series has been certified certified according to EN 81-1:1998+A3:2009 and EN81-20:2014
(Clause 5.9.2.5.4 d) and 5.9.3.4.2 d)) to be used without motor contactors. Same contactors that can
be removed, nowadays are used to short circuit motor phases when lift is stopped.
An alternative solution when main contactors are removed, can be to use a power relay (or mini
contactor) governed by the inverter, in order to short circuit motor phases when lift is stopped. This
power relay (or mini contactor) can be directly wired to the dedicated U0, V0 and W0 terminals.
Inverter short circuits motor phases when no current is flowing from the inverter to the motor,
therefore the relay or contactor doesn’t need to be sized according to motor’s rated power.
2-187