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800.727.5646 automatictiming.com Automatic Timing & Controls 305E Series
Electromechanical Timer // 305E Series
9
Noted for its circuit flexibility, the 305E also provides the highest accuracy
among analog timers. Available for either ON-Delay or OFF-Delay
operation.
The 305E provides delay, interval or pulse timing function for up to 7
load circuits through two instantaneous and two delayed switches. It
features a plug-in design and cycle progress indication.
HIGHEST ACCURACY: Because of its exclusive infinite engagement
clutch, the 305 has a repeat accuracy of 0.2%, highest of any timer in
its class.
PLUG-IN AND DUST-TIGHT DESIGN: By virtue of its true plug-in design,
the body of a 305E can be replaced in seconds without disturbing the
housing or disconnecting the wiring. Its gasketed dial assembly forms a
dust-tight seal against the housing, whether panel or surface-mounted.
FASTEST RESET: All 305 timers reset to a full-scale setting within 0.1 second,
proportionately faster for shorter settings.
CIRCUIT FLEXIBILITY: All the contacts of its two instantaneous and two delayed
load switches are externally accessible at a 14 point terminal block.
LONGEST LIFE: With an average mechanical life expectancy of over 5,000,000 operations
before the first failure, the 305E is the leader in its class.
PILOT LIGHT: A built-in pilot light indicates that the timer is running.
Moto r -Dr i ven Ana l o g R e s e t T i m er
BLACK—Circuit Closed
GRAY—Circuit Open
SWITCH CONTACTS
ON DELAY
Timing Sequence**
Before
Start
During
Cycle *
End of
Cycle
Instantaneous
14-9/6-8
14-10/6-7
Delayed (D2)
11-12
11-13
Delayed (D1)
4-5
4-3
*D2 trips approximately 1/2% of range after end of cycle.
** Assumes a sustained closed start signal (i.e. longer than the dial set time).
SWITCH CONTACTS
OFF DELAY
Timing Sequence**
Before
Start
During
Cycle *
End of
Cycle
Instantaneous
14-9/6-8
14-10/6-7
Delayed (D2)
11-12
11-13
Delayed (D1)
4-5
4-3
*D2 trips approximately 1/2% of range after end of cycle.
** Assumes a sustained open start signal (i.e. longer than the dial set time).
Shown power on.
The 305E is a synchronous motor-driven timer with an electricallyoperated
clutch equipped either for ON-Delay or OFF-Delay
operation.
ON-DELAY: When power is applied (start signal on), the clutch
solenoid is energized. Two things happen immediately and simultaneously,
the instantaneous switches transfer from one set of
contacts to the other, and the motor begins to drive the cycle
progress pointer toward zero.
At the end of the timed period, the pointer trips one of the
delayed switches, a brief time later (about 1/2% of full scale), the
other delayed switch is tripped, stopping the timer motor but
leaving the clutch engaged. The timer does not reset until power
to the clutch is removed.
OFF-DELAY: Timing starts when power is removed (start signal
off), from the spring-loaded, normally engaged clutch. The timer
is reset when power is restored to the clutch solenoid; simultaneously,
the instantaneous contacts are tripped. Action of the
delayed contacts is the same as with ON-Delay timers. A power
outage stops the motor but does not reset the OFF-Delay 305E.
\\\OPERATION
