Current Alarm Function
6-
181
Current Alarm Function
This function displays a current alarm (HCA) on the Digital Operator and outputs a minor fault contact
signal
*
when the Inverter output current exceeds 150% (effective value) of the rated output current. Use
this function to check the current during trial operation for machines that increase Inverter output current,
such as elevating machines.
*To output a minor failure contact signal from a multi-function contact terminal, set H2-
to 10 (Minor failure).
If a current alarm occurs frequently, reduce the Inverter load.
Use the peak hold current monitoring function (U1-83 and U1-84) when performing retuning to reduce
the Inverter output current to 150% of the rated output current. Refer to
Chapter 4 Trial Operation
for
details.
■
Related Constants
* Applicable for G7-Series Inverters with software versions PRG:1039 or later
If load is applied to an induction motor at startup before motor magnetic flux has been produced (as when
acceleration starts while the motor is locked by a brake mechanism or acceleration is too sudden), a high start-
ing current may flow.
In this case, use the following functions and constants to accelerate the motor after the magnetic flux is pro-
duced.
Startup current can be reduced by producing motor magnetic flux.
•
Magnetic flux compensation function (See related constants b2-02 and b2-08)
•
Dwell function (See related constants b6-01 and b6-02)
•
Initial excitation function (See the setting 60 of the multi-function contact input H1)
For flux loop vector control, a multi-function input terminal can be used for initial excitation by setting
H1-
to 60.
•
Field forcing function (See related constant d6-03)
IMPORTANT
For applications where a high current flows because of frequent start and stop operations, such as cranes, set L8-41 to 1
(Enabled).
If a current alarm occurs frequently, take measures such as:
• Reducing the frequency of operation and loading.
• Adjusting open/close timing of holding brake.
• Increasing acceleration/deceleration time.
• Taking enough time to produce motor magnetic flux (As described below).
Con-
stant
Number
Name
Description
Setting
Range
Factory
Setting
Change
during
Opera-
tion
Control Methods
MEMO
BUS
Regis-
ter
Display
V/f
V/f
with
PG
Open
Loop
Vector
1
Flux
Vec-
tor
Open
Loop
Vector
2
L8-41
*
Current alarm
Allows or restricts an alarm from
being triggered when the relative
output current rises above 150%.
0: Disabled.
1: Enabled (alarm will be
output).
0 or 1
0
No
A
A
A
A
A
4F2H
HC Alarm Sel