BRUEL & KJAER 2305 - Mechanical System Components

SPEED, LOWER LIMITING FREQUENCY and POTENTIOMETER RANGE.
When the two first knobs are combined so that their settings correspond to
points inside the hatched area in Fig . 2.2 on page 24, the writing system will
always be in a stable condition, presuming that the POTENTIOMETER
RANGE knob is set according to the Range Pot e ntiometer used . For instance
at "50" for a 50 dB Rang e Potentiometer. Wh en settings are chosen outside
the hatched area, the writing system lends to overshoot and to be unstable .
.
0000000000 0000000000000 00 0000000000000 0000000000 0
W. S' IW .'
Paper Spied .100 mm/ •• c. -_
W.S.· Writing Sp.ed In mm/.lc.
Fig. 1.5. Curves showing the influence of the writing speed upon the recording
of an input step voltage on 100 mm paper.
Mechanical System.
The Level Recorder Type 2305 is designed to fulfil a number of operational
requirements in combination with other Briiel & Kjrer instruments and yet
at the same time be remotely controlled . To carry this out, various
mechanica 'l gears, clutches and electromechanical switches are necessary ,
Principle. In Fig. 1.6 the mechanical drive system is illustrated, and with the
aid of this figure the working principle will be explained.
The motive power is supplied from the self-starting synchronous motor via
a
worm drive to the electromagnetic clutch . From the clutch the power is
transferred to a gear-box via the two nylon gear wheels 1 and 2. The gear-
box (described below) has two output shafts, Drive Shaft 1 and Drive Shaft II,
the speeds of which can be chosen by the PAPER SPEED and DRIVE
SHAFT SPEED knobs respectively .
Drive
Shaft 1. This has a fixed gear wheel 3 which among others drives the
reduction gear sets 4, 5 and 6, 7. The set 6, 7 is free-running on the Drive
11