Chapter 12 Troubleshooting MASTER-K
12-9
12.4.2 Output circuit troubles and corrective actions
Condition Cause Corrective Action
When the output
is Off, excessive
voltage is
applied to the
load
• Load is half-wave rectified inside
(in some cases, it is true of a solenoid)
• When the polarity of the power supply is
as shown in ℵ, C is charged. When the
polarity is as shown inℑ, the voltage
charged in C plus the line voltage are
applied across D. Max voltage is approx.
22 times of rated voltage
If a resistor is used in this way, it does not
cause a problem to the output element. But
it may make the performance of the
diode(D), which is built in the load, drop to
cause problems
• Connect registers of tens to
hundreds kΩ across the load in
parallel
The load does
not turn OFF
• Leakage current by surge absorbing
circuit which is connected to output element
in parallel
• Connect C and R across the load,
which are of registers of tens kΩ
When the wiring distance from the
output module to the load is long,
there may be a leakage current due to
the line capacity
When the load is
C-R type timer,
time constant
fluctuates
• Leakage current by surge absorbing
circuit which is connected to output element
in parallel
• Drive the C-R timer using the relay.
• Use other timer than the C-R timer.
Some timers have half-ware rectified
internal circuits therefore, be cautious.
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