TOSHIBA
6F9EOlll
7.4 Detection of Starting Current and Starting Time
The SZE21 checks a motor current to detect whether the motor is stopped.
starting, running or overloaded.
The detection conditions are as follows:
(1)
Stopped:
When the motor current is less than 5% of the motor's rated
current
(IN).
(2)
Starting:
From the time when the motor current exceeds 1.5 times the
motor rated current
(IN)
as it leaves the stopped condition
until the motor current falls below 1.5 times the motor
rated current.
(3)
Running:
Not during the starting period. when the motor current is
higher than 5% of the motor rated current. but lower than a
current that will trigger the overload
(OL)
function.
(4) Overloaded: Not during the starting period, when the motor current exceeds
the operating value for the overload
(OL)
function.
’
I
________
I(
_____
er
current
__________
________.
_________________------
m:g;e::ting
point
_______________________
-----_-
L
----~---------~----.~-.-----.--.~----.--------~~~---~.-.~-.--.
_
O.D5
x IN
(1)
.,
(2)
.I,
(3)
I,
(4)
J,
(3)
J,
(1)
T
4.
4.
I.
A-.
--
--
(1) Starting current
The starting current is a current value that exists 100 ms after the relay
has detected that the motor is starting. The starting current is obtained
by taking an average of five starting currents.
(2) Starting time
The time 2 shown in the diagram above is taken as a starting time.
T,he
,
sta"ting time is obtained by taking an average of five starting times.
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114
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