Text preview for : TSV70 MK2 - 11-15.pdf part of Farnell TSV70 Instruction manual (includes schematics) for the TSV70 Power Supply made by Farnell UK.
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and an wlth the RN{GE swltch on the,7o\r,,5A positlon aruneter connected across the output aceurate external LruIT '.boittrol to gtve a ad1ust the "CIAREDS1 termltt"i", the set T1o3 untll on thls tneter. readlng of 5 "rp" scale) panel anrneter reads 5 amps (full front . .
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SECTION Vl
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I) SERIES OPERATTON
Unlts uray be connected tn serles to provlde higher It Ls recommended that a Protectlve otrtput voltages. across the output terminal of each unLt, dlode is. fltted terminal to prevent the supplies cathode to posltive The becoming reverse biased under overload qondltLons. diode should have a current ratLng equal'to the maximum ft ls reconmended that of the unLt. output capabllity not more than three units be series connected.
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2'
PARALLEL OPERATTON
to increase the "' Units may be conneCted in parallel them the unLts In order to parallel current capability. should be adjusted for equal output voltage and their In such a output terminals then connected ln parallel. system, as output load current ls Lncreased from zero, the rrnLt havlng the htghest voftage setting wlll conduct The unit with untLl it.reaches lts current limit poLnt. it the next highest voltage will then conduct until polnt and so on. The V/I reaches lts current lintt of a system of three units connected ln characterlstic parallel ls shown in flgure 2.P14!his shows a serles of descendlng steps in voltage as the load current increases. The nagnitude of the step depends on how closely the The resolution of the voltages can be set together. fine potentJ.oneter is approximately tOmV hence the steps No more than in voltage could not be lower than lOnV. three units should be operated ln parallel. 3) EXTERNAL SENSINGOPERATION Unlts are supplled wlth Llnks between the SENSEand If tt ls required to correct for the OUTPtn terminals. voltage drop along the leads carrylng current to the load, lt ls. posslbte to use a four terminal connection. It ls not posstble to correct for more than I volt drop in each lead. of lead from the senslng terminals and iaaition output ternl.nals Lncreases the lnductance Ln the . feedback pathr. whlch cogld give rise to Lnstablllty'at htgh frequencles unless the followlng precautions'are taken. , The leads from the + otIfPUT and + SENSEtermlnals The leads from the nshould be twlsted together. "- SENSE" termlnals should be twlsted OUTPUTtr and together SLnce inductance is Lntroduced.between the output termlnals and 'the Load, the transLent performance of Thls may the supply at the load is adversely affected.
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be restored by addl-ng a capacitor of approxlmately across the Load 1OOvolts dlrectly
2OOOuFat
It may also be necessaqy to decouple the outPut and senslng termLnal pairs wlth low voltage electrolytlc For the '+ OIIIPIXI and + SENSE tennlnal palr the capacltors. capacLtor posLtlve shouLd be connected to the + OITPIII termlnal and for the - OUTPIIT rnd - SENSEterrnlnal paLr, the should be.connected to the - SENSEtermLnal. capacitor posltive NOTE: FROU THE CARE I.IUST BE TAKEN NOT TO DRAWLOAD CURRENT
SENSE TER}IINALS. TYPICAL PERFORMANCE. STABII,ITY.
I
Output voltage causes.
changes are due maLnly to the followlng
t
a) Load change. b) llalns supply change. c) Conponent temperature (a) Load Change. (I) Steady load - for from zero to full page holds.
change.
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a change ln steady load on load, the speclfLcatlon
(1I) (111)
Translent response - Tlplcal response to a pulsed load ls shown ln flgure 3. P.14. load Output lmpedance for alternating superimposed on a steady load, the output lnpedance of the supply lncreases wlth frequency due to faII off Ln galn of, the lt ls until eventually control ampllfler, and lead determined by the output capacltor lnductance. A typlcal output lmpedance,/ frequency curve is shown I,n f lgure 4. P.15. Chanqe.
(b)
Malns supplv
Surges on the malns ln the forrn of short rlse tlme pulses may be fed on to the output tcrnLnals by stray $lhen monltorlng the output waveforrn, capacLtances. both oscllloscope leads should be connected to the same output termLnal- before making a measurement to engure that pulses whlch may not appear across the output ternlnala are not present, to flt (c) Irlhere malns borne pulses exLst lt some form of maLns lnput fllter Change. nay be necessarY to the malns lead.
Component Tenperature
Output virrLatLon is caused by component value The tenperature change due to temperature change.
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.F
change can be:
(1) (11)
A s a result or
of amblent tenperature
chan$E
ttnPerature change As 'a .result of lnternal Ln load or malns lnput to caused ,by change the unLt. temperature Amblent change - the typlcal r of output voltage, at constant coefflclent load and'constant maLns lnput ls O.O2t per degree centigrade. Internal change - a typlcaL plot of output against tlme for changes ln variation mains l.nput and load Ls shown Ln f igure 5. P .1 5 .
(r)
(11)
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flo0
120
0
o fio o 10 o5
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t0
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o l l l* o
o
t l
230
220
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tl
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210
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o
r 10H5
o
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FIGUREt -
TRAI{SFORilER PRIilARY COililECTIO}lS.
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