Fuji Electric FRENIC-MEGA, Instruction Manual

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6-1
Ch
ap. 6
TROUBL
ESHO
O
TING
Chapter 6 TROUBLESHOOTING
6.1 Protective Functions
The FRENIC-MEGA series of inverters has various protective functions as listed below to prevent the system from going down and
reduce system downtime. The protective functions marked with an asterisk (*) in the table are disabled by default. Enable them
according to your needs.
The protective functions include, for example, the "alarm" detection function which, upon detection of an abnormal state, displays
the alarm code on the LED monitor and causes the inverter to trip, the "light alarm" detection function which displays the alarm code
but lets the inverter continue the current operation, and other warning signal output functions.
If any problem arises, understand the protective functions listed below and follow the procedures given in Sections 6.2 and onwards
for troubleshooting.
Protective function Description
Related
function code
"Alarm" detection
This function detects an abnormal state, displays the corresponding alarm code, and
causes the inverter to trip. The "alarm" codes are check-marked in the "Alarm" object
column in Table 6.1. For details of each alarm code, see the corresponding item in the
troubleshooting.
The inverter retains the last four alarm codes and their factors together with their
running information applied when the alarm occurred, so it can display them.
H98
"Light alarm" detection*
This function detects an abnormal state categorized as a "light alarm," displays
l-al
and lets the inverter continue the current operation without tripping.
It is possible to define which abnormal states should be categorized as a "light alarm"
using function codes H81 and H82. The "light alarm" codes are check-marked in the
"Light alarm" object column in Table 6.1.
For how to check and release light alarms, see Section 6.5 "If the "Light Alarm"
Indication (
l-al
) Appears on the LED Monitor."
H81
H82
Stall prevention
When the output current exceeds the current limiter level (F44) during acceleration/
deceleration or constant speed running, this function decreases the output frequency to
avoid an overcurrent trip.
F44
Overload prevention
control* Before the inverter trips due to a heat sink overheat (
0h1
) or inverter overload
(
0lu
), this function decreases the output frequency to reduce the load.
H70
Automatic deceleration*
(Anti-regenerative
control) If regenerative energy returned exceeds the inverter's braking capability, this function
automatically increases the deceleration time or controls the output frequency to avoid
an overvoltage trip.
H69
Deceleration
characteristics*
(Excessive regenerative
energy proof braking
capability) During deceleration, this function increases the motor energy loss and decreases the
regenerative energy returned to avoid an overvoltage trip (
0u
).
H71
Reference loss detection*
This function detects a reference frequency loss (due to a broken wire, etc.), continues
the inverter operation at the specified frequency, and issues the "Command loss
detected" signal
REF OFF .
E65
Automatic lowering of
carrier frequency Before the inverter trips due to an abnormal surrounding temperature or output current,
this function automatically lowers the carrier frequency to avoid a trip.
H98
Dew condensation
prevention*
Even when the inverter is in stopped state, this function feeds DC current across the
motor at certain intervals to raise the motor temperature for preventing dew
condensation.
J21
Motor overload early
warning*
When the inverter output current has exceeded the specified level, this function issues
the "Motor overload early warning" signal
OL before the thermal overload protection
function causes the inverter to trip for motor protection. This function exclusively
applies to the 1st motor.
E34
E35
Auto-reset*
When the inverter has stopped because of a trip, this function allows the inverter to
automatically reset and restart itself. (The number of retries and the latency between
stop and reset can be specified.)
H04
H05
Forced stop*
Upon receipt of the "Force to stop" terminal command STOP , this function interrupts
the run and other commands currently applied in order to forcedly decelerate the
inverter to a stop. H56
Surge protection
This function protects the inverter from a surge voltage invaded between main circuit
power lines and the ground.
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