Current Alarm Function
6-
183
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 and 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
TOE-S616-60.1.book 183 ページ ２０１７年８月４日 金曜日 午後３時４１分