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1.
DESCRIPTION
Detailed Functioning of the Relay Arrangement.
The synchronous motor of the 2305 is running continuously and, as can be
seen from Fig. 1.16 the start of the paper-drive is obtained by disconnecting
the 24 V supply across the clutch coil. Since the relay 01 is connected in
parallel with the clutch coil, the synchro-starter is only connected to "Filter
Input" when the paper drive is stopped. The relay circuits for 01, 02 and 03
are all sketched in Fig. 1.17. The relays are shown in their released position.
Before connecting the 4409 the Level Recorder should be started by setting
the controls as shown on Fig. 2.1 and 2.2. When connecting the 4409 to the
2305, the relay 03 then short-circuits the single chart push button which
otherwise should have been lifted up to obtain the automatic stop. The
paper-drive stops as soon as the automatic stop switch is closed by the cam
and the 24 V supply is applied to the clutch.
When the looo Hz start signal arrives through the Filter
Input,
the relay 02
is energized which in turn causes 03 to be energized whilst "Single chart"
is still short circuited, but now by 02.
When the 1ooo Hz start signal ceases, 02 is released, but 03 is still energized
since its coil has a much larger resistance than the clutch coil which is fed
in series with it from the 24 V supply.
The short-circuit across "Single chart" is therefore interupted and the clutch
is released, starting the paper drive.
03 is finally released by the cam releasing the automatic stop switch.
16
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