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| DSH 440- V3 e) N, h4 E( j7 z5 M
( a9 w/ K$ b: A/ p# P' M | Short-circuit of motor capacitors
" U, f7 V+ ]) [+ i | 19.7% X' P$ V$ e; x, H! `
| 60335-1(ed.3)
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Standard: IEC60335-1:1991, 3rd Ed.# `, s) i1 P9 |6 Y
Sub-clause: 19.7
: k/ q1 {8 ]1 M. A9 Q' kSheet No. DSH-440" a& v" j7 K3 j0 y! v5 K, z, i2 O
Subject: Short-circuit of motor capacitors8 `6 E& l: T& B' X3 }6 F7 d
Key words: -short circuit -motor capacitor
4 {$ q% X4 n% F% C1 x5 cDecision taken at the 40th CTL meeting 2003.& I2 j: E, ~1 G# C
Question:
+ H1 [, {9 O' PTC 61 requested CTL to clarify the test procedure for short-circuiting capacitors in accordance with Sub
$ c# l, H z" i3 B) A5 v# P' s9 dclause 19.7 of IEC 60335-1.
- R. H$ T* R; I$ Z5 bDecision:
) b9 P" F! j$ P. BIf the design of the circuit is such that short-circuiting of one capacitor will result in the short-circuiting+ U5 n8 [$ d% X
of the second capacitor, only one capacitor needs to be short-circuited. This is endorsed by the sub clause4 X5 G, @7 ^3 }' \- f. t. m) ~
4.3 that states “If it is evident from the construction of the appliance that a particular test is not8 i! C/ Y2 K( t1 u, S# a
applicable, the test is not made”.
0 q: S0 f1 E! tThe followings are examples of the circuits.. F; w' q. x2 L8 T# l2 y
In the Example A:
. z% s6 v; T; |5 g3 K$ dShort-circuit of capacitor (Cb) terminals is necessary according to the requirements. For the
! u# a7 D% u; b& |" h; ^" H( i9 kcapacitor (Ca), short-circuit of its terminals when motor is running is not necessary because$ W8 C( @- _& S# w: B" T4 H7 i2 u
the circuit is opened (the switch is opened).; G7 B$ ^6 ~2 z$ A" h g
Also short circuit of its terminals (Ca) when the motor starts is not necessary because it is+ d- R0 y9 B6 g/ a2 M$ e* K
already covered by the short-circuit of Cb terminals.
6 z; w5 [/ n J3 p1 ?In the Example B:. {1 Z9 c' s$ E' P* w
Only one short-circuit, either Cb1 or Cb2 terminals, is necessary because the testing of one# O% x! A! K' m u
covers the testing of the other one. Also the short-circuit of Ca terminals is not necessary
; n! }$ K1 Q p0 j# Ubecause of the reason stated in the Example A.
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