CARLO GAVAZZI RVBS, Manual

Page: 37 / 46

Motor Controllers AC Variable Frequency Drives
RVBS
Specifications are subjected to change without notice.10/08/2021
36
Data for H07 Function
0
Disable
An over-current trip occurs at the instantaneous over-current limiting level.
1
Enable
The current limiting operation is effective.
➢
If any problem occurs when the motor torque temporarily drops during current limiting processing, it is
necessary to cause an over-current trip (H07 = 0) and actuate a mechanical brake at the same time.
➢
The similar function is the current limiter specified by F25 and F26. The current limiter (F25, F26)
implements the current control by software, so an operation delay occurs. When you have enabled the
current limiter (F25, F26), also enable the instantaneous over-current limiting with H07 to obtain a quick
response current limiting.
➢
Depending on the load, extremely short acceleration time may activate the current limiting to suppress the
increase of the inverter output frequency, causing hunting (undesirable oscillation of the system) or
activating the inverter overvoltage trip. When specifying the acceleration time, therefore, you need to
consider machinery characteristics and moment of inertia of the load.
Function
code
Mod.
add.
Description Def Min Max U.M. R/W
H07 0x0307
Instantaneous Over-current Limiting
(Mode selection)
1 0 1 - R/W
4.4.3
Motor overload prevention
H12 specifies the decelerating rate of the output frequency to prevent a trip from occurring due to an overload.
This control decreases the output frequency of the inverter before the inverter trips due to a heat sink overheat
or inverter overload (with an alarm indication of OH1 or OLU, respectively). It is useful for equipment such as
pumps where a decrease in the output frequency leads to a decrease in the load and it is necessary to keep
the motor running even when the output frequency drops.
Data for H12 Function
0.00 Decelerate the motor by deceleration time 1 (F08) or 2 (E09)
0.01 to 100.00 Decelerate the motor by deceleration rate from 0.01 to 100.00 (Hz/s)
999 Disable overload prevention control
➢
Note: In equipment where a decrease in the output frequency does not lead to a decrease in the load, the
overload prevention control is of no use and should not be enabled
Function
code
Mod.
add.
Description Def Min Max U.M. R/W
H12 0x030C Overload Prevention Control 32767 0 32767 0.01Hz/sec. R/W