Page 68 - IDEC timer catalogue

General Instructions Timers

General Instructions for All Timer Series

Switches & Pilot Lights With inductive, capacitive, and incandescent lamp loads, inrush current more Excessive vibration or shocks can cause the output contacts to bounce, the
Load Current
Vibration and Shock
timer should be used only within the operating extremes for vibration and shock
than 10 times the rated current may cause welded contacts and other undesired
resistance. In applications with signifi cant vibration or shock, use of hold down
effects. The inrush current and steady-state current must be taken into consider-
ation when specifying a timer.
Time Setting
Contact Protection springs or clips is recommended to secure a timer to its socket.
Switching an inductive load generates a counter-electromotive force (back EMF) The time range is calibrated at its maximum time scale; so it is desirable to use
in the coil. The back EMF will cause arcing, which may shorten the contact life the timer at a setting as close to its maximum time scale as possible. For a more
and cause imperfect contact. Application of a protection circuit is recommended accurate time delay, adjust the control knob by measuring the operating time
Display Lights Temperature and Humidity Input Contacts
with a watch before application.
to safeguard the contacts.
Use the timer within the operating temperature and operating humidity ranges
driving the timer with a solid-state output device (such as a two-wire proximity
and prevent freezing or condensation. After the timer has been stored below Use mechanical contact switch or relay to supply power to the timer. When
its operating temperature, leave the timer at room temperature for a suffi cient switch, photoelectric switch, or solid-state relay), malfunction may be caused by
period of time to allow it to return to operating temperatures before use. leakage current from the solid-state device. Since AC types comprise a capaci-
tive load, the SSR dielectric strength should be two or more times the power
Environment voltage when switching the timer power using an SSR.
Relays & Sockets Avoid contact between the timer and sulfurous or ammonia gases, organic sol- power to a timer or its signal inputs. When using solid state devices, be cautious
Generally, it is desirable to use mechanical contacts whenever possible to apply
vents (alcohol, benzine, thinner, etc.), strong alkaline substances, or strong acids.
of inrushes and back-EMF that may exceed the ratings on such devices. Some
Do not use the timer in an environment where such substances are prevalent. Do
timers are specially designed so that signal inputs switch at a lower voltage
not allow water to run or splash on the timer.
than is used to power the timer (models designated as “B” type).

Timing Accuracy Formulas
Timing accuracies are calculated from the following formulas:

= ± 1 x Maximum Measured Value – Minimum Measured Value x 100%
Repeat Error
Timers 2 Maximum Scale Value
Voltage Error = ± Tv - Tr x 100%
Tr
Tv: Average of measured values at voltage V
Tr: Average of measured values at the rated voltage
= ± Tt - T20 x 100%
Temperature Error
T20
Tt: Average of measured values at °C
Terminal Blocks T20: Average of measured values at 20°C Maximum Scale Value
= ± Average of Measured Values - Set Value x 100%
Setting Error

Circuit Breakers

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