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12.7 Thermal test in regard to fault conditions in lamp controlgear or electronic
' o6 {( O1 s" n& P2 Odevices in plastic luminaires
4 M* p) K' R! W; F4 TThe test applies only to luminaires with a thermoplastic housing not fitted with an extra
$ i6 Q5 ?$ \: R1 G! \& Umechanical temperature-independent device as per 4.15.2.
7 }! R) X! N3 t( B) A
7 h- v0 W: u/ [12.7.1 Test for luminaires without temperature sensing controls
5 [: P, {' K/ `# L; z1 V& b1 r; lThe luminaire shall be tested under the conditions specified in items a), c), e), f), h) and l) of
\( d% R) B" d0 ?2 i12.4.1. In addition, the following also applies.
/ J- V9 v5 C' Y8 _+ ^1 ?+ k9 h20 % of the lamp circuits in the luminaire, and not less than one lamp circuit, shall be* z6 _- F% P# m4 @ I7 @7 d7 Y5 O& i
subjected to abnormal conditions (see item a) of 12.5.1).
/ u1 K8 k8 M2 c3 J/ VThe circuits which have the most thermal influence on the fixation point and exposed parts
9 ?. E) ?$ a4 O9 Nshall be chosen and other lamp circuits shall be operated at rated voltage under normal: O' _$ U3 v* ]; m! S
conditions.7 E% D' U. b: x6 y; C! ]0 @+ @9 \
The circuits subjected to abnormal conditions shall be operated at 1,1 times (the rated voltage
W1 }! P& K# Tor the maximum of the rated voltage range). When conditions are stable, the highest winding
: u, u1 O8 G$ W5 e5 z9 O. ^. atemperature and highest temperature of fixing points and most thermally influenced exposed
# i/ Z9 Q+ K; L5 Oparts shall be measured. It is not necessary to measure the temperature of small wound
- p- E0 @8 d; S9 b! W6 Adevices that are incorporated within electronic circuits.9 X* p3 s2 [$ G) q
Compliance5 k$ M# ]( t3 K* M# n
The values of the ambient temperature and the temperature measured at 1,1 times (the rated' q! w5 k0 l6 q
voltage or the maximum of the voltage range) are used for the linear regression formula in
% O0 ^- P! h( ?6 v0 U4 V# H8 ]calculating the temperature of fixing points and other exposed parts in relation to a
+ U% e; [0 V9 B4 l: o8 Zballast/transformer winding temperature of 350 °C. The calculated value shall not exceed the: m2 J) c4 C* R" l
temperature of the deflection under load of the material in accordance with method A as
( m$ O; o1 _* t% m- Q+ M( _0 udefined in ISO 75 (1987), Plastics and ebonite – Determination of temperature of deflection
7 a, r( y: G5 E5 V3 Tunder load.
4 V3 F4 B- v2 h- L j* _% V12.7.2 Test for luminaires with temperature sensing controls internal/external to the5 y$ W, O- L9 e2 h
ballast or transformer) k% D& \ z) o2 W- M( i
The luminaires shall be set up for this test as described in the first three paragraphs of 12.7.1.7 c8 s2 E( b* A7 q _/ Q- H; A8 F
2 F; d& P& R0 G6 oThe circuits subjected to abnormal conditions shall be operated with a slowly and steadily
0 P& F9 _& S0 Bincreasing current through the windings until the temperature sensing control operates.
/ f& m: R8 b/ h B1 Z QTime intervals and increments in current shall be such that thermal equilibrium between
! c5 S0 U. r5 Jwinding temperatures and temperature of fixing points and most thermally influenced exposed
9 M. l/ Z5 Q: f/ i4 Zparts is achieved as far as is practicable. During the test, the highest temperature of the spots
( N9 F) Z$ e! I' v! y% a" s6 ^tested shall be continuously measured.) J5 p, |5 k8 G1 z
For luminaires fitted out with manual-reset thermal cut-outs, the test shall be repeated six! o5 b# C3 I4 v5 }0 U
times allowing 30 min intervals between tests. At the end of each 30 min interval, the cut-out7 E# o- D4 Y' |8 Q# Y3 C
shall be reset.* Q5 ?5 U5 t1 |3 g0 N) O
For luminaires fitted out with auto-reset thermal cut-outs, the tests shall be continued until a
# i+ p) y8 b/ h7 N% Wstable temperature is achieved.$ D! l! C* {2 e |" x' X& F" A
Compliance4 T2 e. n5 Q; I! f
The highest temperature of the fixing points and most thermally influenced exposed parts,; x8 ]! f' d$ q4 w& M' \: g. l
shall not exceed the temperature of deflection under load of the material according to the
9 \9 b+ q: A2 [9 R$ a: r& kmethod A as defined in ISO 75, at any time during the tests for thermal links, manual-reset
# S1 h3 K# u8 x; jthermal cut-outs, and auto-reset thermal cut-outs.
5 Q2 l* l2 r! h2 y G& FIn applying the requirements of 4.15 and 12.7 the following notes are to be referred to:- V/ R9 P7 r! w. u( t- g3 w
NOTE 1 - ‘Fixing points’ means both the fixing points of components and the fixing points of a luminaire to the( Q$ Y6 F3 s0 E
mounting surface.
* B+ |6 G8 z4 q. x5 r! R: T, F. ]& s- b j- ^' }
NOTE 2 - ‘Exposed part’ means the outer surface of the luminaire enclosure.8 G! @# L; p8 k6 ^* R( P
NOTE 3 - Measurement of exposed parts is restricted to those parts providing the luminaire/component fixing or
! [1 m* ~9 ?* w6 s- R) w+ n$ r# Vparts providing a protective barrier against accidental contact with live parts, as required by section 8 of this9 Y& @0 G. j5 r8 ]' ~5 s+ l
standard.
8 i/ ], a2 z9 p& _$ a, UNOTE 4 - The hottest part of the thermoplastic material section requiring test is measured. This may often be on+ u4 T! [. q. _# Y% T; {
the internal surface of a luminaire enclosure not the outer surface.+ T2 ~3 _. Y* ^: ]
NOTE 5 - The material temperature limits defined by clause 12.7 are with respect to materials under both
9 |( L% d; c9 b# J, jmechanical load and no mechanical load.7 C. p( M/ l% v& O
NOTE 6 - The application of clause 12.7 must be read together with the requirements of sub-clause 4.15. |
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