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这个问题已经有CTL决议了。具体如下：
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Question:7 B; L3 Y3 g4 ?
When measuring the circuit capacitance according to clause 2.4, what frequency should be used, 1kHz, the measured frequency of the circuit or another frequency?) E) s4 z# G$ ?7 e. _
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Proposal:
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For frequencies not exceeding 1kHz, the circuit capacitance shall be measured at a frequency of 1kHz.
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For frequencies above 1kHz, the circuit capacitance shall be measured under the actual circuit frequency or the nearest frequency point of the measuring equipment.
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$ m3 u6 v: B" i+ M. J' |: T2 n) h' R; `Decision:4 n0 T& r( i6 y5 T% r7 C
LCC limit values per 2.4.2 typically are applied to two different types of circuits, those providing:
+ K! m. p" U- u, v) v(a) steady state current, or
5 w; \+ A( i* G, }# Z( v8 m4 c(b) capacitively driven current.
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In a single product, one or multiple measurements may be required based on the type
/ _- O0 }. M1 j- g$ p/ u+ ^7 \of individual circuits involved.
( J) M5 l8 J9 l' F- ^3 X/ f• For circuits with steady state current of a single frequency, a measurement through a 2000 ohm resistor is conducted. There is no capacitance determination.2 r$ C1 K+ Z3 V+ k4 B
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• For circuits with steady state current of multiple/complex frequencies, a measurement using one of the measurement instruments of Annex D is conducted. There is no capacitance determination. ?" E, n! h1 |" ~: O, k K
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• For a circuit with a capacitance driven current, such as found in a lamp driver circuit, where the current typically is driven by a ‘single’ capacitor, the circuit capacitance can be determined via either the marked nominal capacitor rating or measurement of the single capacitor via LCR measurement equipment. For circuits that have capacitance driven currents, there are no additional current measurements. It is purely a capacitance determination or measurement, with maximum capacitance defined per 2.4.2, based on the maximum Working Voltage of the circuit.
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' T& J0 M4 b, l7 @Explanatory Notes:
: e7 y" ?& q6 v; ]The methodology stated above also will be included in IEC 62368, but in a different form.5 s& ^: m1 ?# z$ j" S" S) E
- s3 \5 g/ `. P& bWe also understand that most widely and commonly available LCR equipment is not intended to measure complex circuits/networks consisting of multiple L, C & R components in the same network. The equipment is designed to measure individual L, C or R components. Regardless, it is our contention that such measurements of complex circuits by LCR measuring equipment are not required by 2.4.2 of IEC 60950-1. |
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