Thyristors in Railway Traction How can their effects be measured?
Thyristors in Railway Traction How can their effects be measured?
Thyristors in Railway Traction How can their effects be measured?
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AC or DC signals from measur<strong>in</strong>g <strong>in</strong>struments<br />
such as psophometers,<br />
and at the end of each sampl<strong>in</strong>g period<br />
(user selected from 0,1 to 10<br />
seconds) it grades them accord<strong>in</strong>g<br />
to level and stores the result of the<br />
grad<strong>in</strong>g <strong>in</strong> a digital memory. The memory<br />
is large enough to accommodate<br />
65000 samples — up to 180<br />
hours — and the <strong>in</strong>strument may <strong>be</strong><br />
<strong>in</strong>terrogated manually at any time<br />
without <strong>in</strong>terrupt<strong>in</strong>g the sampl<strong>in</strong>g<br />
and record<strong>in</strong>g process.<br />
The Type 4426 has a built-<strong>in</strong> digital<br />
display, but <strong>in</strong> most applications<br />
— — - it is used to output data to a hard<br />
Noise Level Analyzer Type 4426 and Alphanumeric Pr<strong>in</strong>ter Type 2312 comb<strong>in</strong>ed <strong>in</strong> a water- copy u n j t |t c g n |Qt c u m u| atj v e disproof<br />
carry<strong>in</strong>g-case KA 2000 -. • , . .... ..<br />
tribution curves and probability distribution<br />
histograms on the Type<br />
Statistical analVSiS n0iSe which '"te^P* conversation 2306 level recorder, or pr<strong>in</strong>t them<br />
y but do not prevent it. There is no out <strong>in</strong> accordance with a user-pro-<br />
of psophometric sense <strong>in</strong> try<strong>in</strong>g to reduce the level grammed rout<strong>in</strong>e on the alphanum-<br />
• of tra<strong>in</strong>-<strong>in</strong>duced noise, which fluctu- eric pr<strong>in</strong>ter type 2312.<br />
I lUloc ates considerably as tra<strong>in</strong>s come<br />
and go, <strong>be</strong>low the statistical level of All these <strong>in</strong>struments are battery<br />
The annoyance caused by any noise from other sources. operated and very portable, so they<br />
k<strong>in</strong>d of noise experienced <strong>in</strong> a hu- <strong>can</strong> easily <strong>be</strong> used on a test-<strong>be</strong>d. It<br />
man environment (as opposed to Bruel & Kjaer manufacture a is a common contractual requiresay,<br />
an electronic circuit) depends Noise Level Analyser, Type 4426, ment, for multiple-unit roll<strong>in</strong>g-stock<br />
not only on its level and quality, but which has <strong>be</strong>en designed for pre- especially, to put the traction equipon<br />
its statistical properties — the cisely this k<strong>in</strong>d of task. Although its ment through tests on the manufacproportion<br />
of time for which it ex- ma<strong>in</strong> use is the analysis of commu- turer's premises which <strong>in</strong>clude a siceeds<br />
the acceptable level, for exam- nity noise out <strong>in</strong> the field — for mulation of load<strong>in</strong>g conditions expeple.<br />
This applies to psophometric which purpose it is made very por- rienced on the actual railway, and<br />
noise <strong>in</strong> a telephone circuit, once it table (with battery operation) — it is these tests <strong>in</strong>clude evidence of the<br />
reaches the subscri<strong>be</strong>r's handset. no less suited to the analysis of pso- psophometric component of l<strong>in</strong>e cur-<br />
Any telephone network is subject to phometric noise <strong>in</strong> a telephone cir- rent <strong>in</strong> the case of AC EMU's. A<br />
occasional bursts of <strong>in</strong>terfer<strong>in</strong>g cuit or a traction supply. It accepts good way to obta<strong>in</strong> or supply that<br />
Arrangement of equipment for logg<strong>in</strong>g statistical properties of psophometric current<br />
evidence is to connect up a Type<br />
2429 Psophometer, a Type 4426<br />
Noise Level Analyzer and a Type<br />
231 2 Alphanumeric Pr<strong>in</strong>ter.<br />
Record<strong>in</strong>g of Cumulative Distribution curve and Probability Distribution histogram made on the portable Level Recorder Type 2306<br />
17