Current Alarm Function - YASKAWA Varispeed G7 Instruction Manual

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-
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.
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:
IMPORTANT
• 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).
■Related Constants
Name
Con-
stant
Display
Number
Current alarm
L8-41
*
HC Alarm Sel
* 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)
•
Description
Allows or restricts an alarm from
being triggered when the relative
output current rises above 150%.
0: Disabled.
1: Enabled (alarm will be
output).
to 10 (Minor failure).
Control Methods
Change
Setting Factory during
V/f
Range Setting Opera-
V/f with
tion
PG
0 or 1 0 No A A

Current Alarm Function

MEMO
Open Open
BUS
Flux
Loop Loop
Regis-
Vec-
Vector Vector
ter
tor
1 2
A A A 4F2H
6-
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