Quattro DC Drive Sequencing
32
ABNORMAL operating sequence
1. If a Drive Fault occurs the Drive will
immediately open the motor contactor, de-
energize any Brake and Drive OK Relays
if so programmed. May be caused by:
a. “Fatal Error” drive Faults including loss
of serial communications
b. Opening of the contactor power Safety
circuit while the contactor is pulled in
c. Loss of correct motor contactor or
Brake Relay feedback.
2. If an Alarm occurs, the drive will signal an
Alarm but continue to run. May be caused
by:
a. Drive Alarms including motor overload,
and drive over temp warning
b. Loss of correct feedback from Brake
Hold relay or Brake Switches
c. Open motor thermostat circuit
d. Speed command is held at zero due to
conflict with the analog speed
command polarity and the run up/ run
down logic
e. The drive is or was being limited by
the motor torque limit setting (Hit
Torque Limit)
f. Speed feedback is failing to properly
track the speed reference (Speed Dev)
g. AC input voltage drops below user
specified percent of the input line to
line voltage
Quattro Pre-Charge
When power is first applied to the Quattro
drive, or after it has shut itself down via a
DSPR time-out, the internal DC bus must be
pre-charged before operation can resume.
The following sequence will occur:
1. Power is applied to the Quattro drive
a. Control power may be applied before or
after 3-phase main power
b. Drive controls should become active
but no contactors should operate
2. Quattro drive receives command to
‘energize’
a. This command may be from serial link
software or hardware logic command to
deliver motor field current in
preparation to start.
b. AC input voltage from mains is
measured and verified to be adequate
according to the setting of the VAC-
input adjustment parameter.
c. Pre-charge contactor PCM is then
pulled in. This provides resistor limited
inrush current to DC bus capacitors
from AC mains and internal rectifier.
3. DC bus is Pre-Charged
a. With pre-charge contactor PCM closed,
voltage builds up on the internal DC
capacitors.
b. DC Bus voltage is monitored during
pre-charge to verify proper voltage
build-up vs time. (See 6.a. below)
c. Target bus voltage is measured input
VAC X √2.
4. Mains contactor is closed
a. As measured DC bus voltage nears
target value the main utility power
contactor UTM closes.
b. Aux contact feedback from UTM
indicates to controls that main utility
contactor is closed.
c. Then Pre-charge contactor PCM is
opened. (See 6.b. below)
5. Boost converter is turned ON.
a. DC bus voltage is boosted to a higher
level as programmed by the Boost
voltage parameter (A5) in order to
achieve near unity power factor and low
harmonic content of the Quattro drive.
b. Motor field controls also turn ON to
begin regulating motor field current
and/or operate main motor armature
circuits.
c. The boost converter will remain ON as
long as any field or armature current is
being provided to the motor. (See 6.c.
below) Time-out of the DSPR (Drive
Stand-by Power Reduction) feature or
other command may turn the Boost
converter OFF when drive is idle. In
that case as new pre-charge cycle must
occur before drive re-start.
6. Problem prevention
a. If DC bus voltage does not rise at the
expected rate to the expected voltage
level during pre-charge a “Charge
Fault” is declared.
b. UTM and PCM are interlocked with aux
contacts such that UTM cannot be
picked unless PCM is already closed.
Once picked, an aux contact of UTM
seals the same circuit allowing PCM to
be dropped with UTM remaining ON.
c. In the event of a major drive Fault, UTM
will be opened to disconnect utility lines
from main power devices of Quattro.
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