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Chapter 4 - Troubleshooting
Phenomena
Causes
Abnormal time
l
when load is a
C-R type timer
l
Load cannot
be off (DC)
l
l
l
If a large current load such as solenoid,
(time constant L/R is large) is directly
operated by the transistor output.
Off response
from load
takes a longer
time.
l
l
Leakage current from surge absorbing
circuit connected to an output element in
parallel.
Circulating current resulting from two
different power source.
It circulates if E1< E2.
It circulates even when E1 is Off (E2 is
On).
Over current at Off
Since current is allowed through diode
when transistor output is off, it may be
delayed for 1s and longer depending on
load.
Inrush current of glow lamp
Measures
Operate the C-R type
l
timer by mediating a
relay.
Use other one but a C- -R
l
type timer.
Note: A timer's internal
circuit may have half-wave
rectification.
Adjusting plural to
l
singular power source.
Connecting to circulating
l
current preventive diode.
See the following figure.
Insert a magnetic
l
connector and others for
which time constant is
small as presented in the
figure and operate load
by the contact.
To restrict inrush current,
l
it must allow dark current
that is 1/3 ~ 1/5 of the
rated current of glow
lamp.
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