Specifications

Altivar
®
31 Adjustable Speed AC Drives
Functions
© 2004–2005 Schneider Electric All Rights Reserved
42
4/2005
When the spooling function is configured, the ramp type is forced to linear
ramp.
Current limit switching
To limit the torque and the temperature rise of the motor, a second current
limit can be configured between 0.25 and 1.5 times the nominal drive current.
Switching between two current limits is enabled using a logic input or a bit in
a Modbus or CANopen control word.
Limiting low speed operating time
This function, suited for automatically stopping or starting pressure-regulated
pumps, stops the motor after operating for a specified period at low speed
(LSP) with zero reference and a run command present. The motor restarts
automatically on the ramp when the reference reappears or when the run
command is broken, then re-established.
The time is adjustable between 0.1 and 999.9 seconds. The factory setting
is 0, corresponding to an unlimited time.
Motor switching
Motor switching allows two motors with different ratings or characteristics to
be supplied alternately by the same drive. Switching must occur with the
drive stopped and locked, using an appropriate sequence at the drive output.
Motor switching is enabled by a logic input or a bit in a Modbus or CANopen
control word. In hoisting applications, motor switching enables the use of a
single drive for vertical and horizontal movements. The function adapts the
motor parameters, switching the following parameters automatically:
• nominal motor voltage
• nominal motor frequency
• nominal motor current
• nominal motor speed
• motor cosine Phi (power factor)
• selection of the type of voltage/frequency ratio for motor 2
• IR compensation, motor 2
• motor frequency loop gain
• motor stability
• motor slip compensation
NOTE: This function disables motor thermal protection.
qSH
trHtrL
qSL
Base reference + trH - qSH
Base reference + trH
Base reference
Base reference - trL + qsL
Base reference - trL
LI or bit
Wiring check trC
RUN command
Motor
speed
Ramp ACC
Ramp 0.1 s
Ramp dEC
Ramp 0.1 s
Start of function
End of function
563699.eps
t
t
t
Configuration of current switching with PowerSuite software
563719
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