FujiFilm FRENIC5000G11S Series, Technical Information

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Chapter 7
2. Common Specifications
7-5
7
• Pick-up operation
An operation that smoothly initiates an inverter operation
sequence without shutting down the motor even though the
fan or other component is rotating under the influence of
natural phenomena such as wind.
• Line/Inverter switching operation
A built-in circuit in an inverter that switches between commer-
cial and inverter operations.
• Slip compensation control
A mode of control in which the output frequency of an inverter
plus an amount of slip compensation is used as an actual
output frequency to compensate for motor slippage.
• Torque limiting
A mode of control in which a limit value is set for the torque so
the frequency is varied to hold the torque within that value.
• Droop control
A mode of control in which a balance is maintained between
two motors used to drive a single load by using a negative
amount of slip compensation.
Two concurrently running motors never have identical load
factors because they have their own specific mechanical
variations. The difference in load factors produces motor
slippage, causing them to run at different speeds in an
unbalanced manner.
As a result, either a motor could have a greater load than the
other or could run erratically.
To control this phenomenon, the speed of either motor (for
example, motor 1) is set higher than the other motor (motor 2),
and inverter 1 is set to provide a negative amount of slip
compensation (droop).
Whichever motor having the higher rpm (motor 1) will slip
because it has a greater load factor than the other. Further,
the negative amount of slip compensation adds to the slow-
down of the motor, so that motor 1 will ultimately run at an rpm
that is well-balanced with motor 2, in terms of load.
• PID control
The scheme of control that brings controlled objects to a
desired value quickly and accurately, and which consists of
three categories of action: proportional, integral and derivative.
Proportional action: Minimizes errors from a set point.
Integral action: Resets errors from a desired value to 0.
• Automatic deceleration
A mode of control in which deceleration time is automatically
extended to prevent the inverter from tripping due to an
overvoltage where a braking resistor is not used.
• Fan stop operation
A mode of control in which the cooling fan is shut down (where
inverter is shut down) if the internal temperature in the inverter
is low when no operation command is issued.
• Motor synchronous speed
Number of revolutions per minute [r/min] of a motor is stated in
an expression as:
N =
120f
[r/min]
p
f: Inverter output frequency [Hz]
p: Number of poles of the motor (4 at factory setting)
• Line speed
Number of revolutions per minute [r/min] of a line load, such as
a conveyor.
• Load shaft speed
Number of revolutions per minute [r/min] of a rotating load,
such as a fan.
• Trip
In response to an overvoltage, overcurrent, or any other
unusual condition, actuation of an inverter’s protective circuit
to cut off the inverter output.
• Alarm
On an inverter, a coded indication of the cause of an interrup-
tion in the inverter output (inverter shut-down caused by a
trip).
• Bar graph
A graphic representation of the output frequency, output
current, and output torque of an inverter on its LCD screen.
• Electronic thermal overload relay
To safeguard a motor, calculations made within an inverter
based on internal data about the characteristics of the motor.
• PTC thermistor
Type of thermistor designed to safeguard a motor.
• Stall
Although expected to stop, an inverter fails to produce the
required torque due to a trip, such as one caused by
overcurrent.
Inverter 1
(Motor 1)
Inverter 2
(Motor 2)
Chapter7-2(P4˜6).p65
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