2 - Fagor Automation

Connection diagrams
10.
CONNECTION DIAGRAMS
Electrical cabinet. Diagrams
354
DDS
HARDWARE
Ref.1209
334
A stop may be caused by:
opening the main power switch - S1, one or several fuses have
blown or there is simply a power outage while the system is running.
The motor brakes with emergency ramps if they were initially set by
parameters. Regardless of the power supply being used, it will not be
possible to return to mains the excess energy generated by braking
(remember that the mains connection has been opened). It causes a
voltage rise at the power bus as a result of saving that energy at the
capacitors.
Remember that the energy saved at the capacitors responds to the
formula: Energy saved = 0.5 C·V ²
When exceeding a certain bus voltage (760-768 V DC) the Ballast circuit
is activated to dissipate that excess of energy in an resistor (internal
or external) and the motor performs a controlled stop (with motor
torque).
Even when having activated the Ballast circuit, if there is a problem
with it (e.g. poor connection of the external resistor) the bus voltage
would keep rising until reaching its maximum value allowed (790 V
DC) and would issue error E215 for bus over-voltage. It would deactivate
the "Drive Enable" function and the motor would stop by friction
without motor torque.
Opening of power contactor - KM1 because the contact KA1 associated
with the relay - KA1 has opened. The braking operation would be
the same as in the previous case when using a PS-65A or a PS-25B4
power supply. If it is a regenerative power supply (XPS or RPS) it
brakes with emergency ramps if they have been previously set by parameters.
The excess energy generated by braking is returned to
mains just a few seconds before opening contactor - KM1 thanks to
the delayed deactivation of the relay - KA3. If for any reason the power
bus voltage kept rising, the braking operation would be the same as
that of the previous case.
Remember that RPS power supplies do not have a Ballast circuit
and if the application requires one, an off-the-shelf circuit will have to
be used.