LM1851 데이터 시트보기 (PDF) - Unisonic Technologies

부품명

상세내역

제조사

LM1851

GROUND FAULT INTERRUPTER

Unisonic Technologies 

UTC LM1851

LINEAR INTEGRATED CIRCUIT

S1 HOT

HOT

LINE

NEUTRAL

GFI

NEUTRAL

RG (0.8) I

1.6

RN RB

0.4 500

(0.2) I

I

UL943 specifies ≤25 ms average trip time under these conditions. Calculation of Ct based upon charging currents

due to normal fault only is as follows:

≤25 ms Specification

-3 ms GFI turn-on time (15k and 1μF)

-8 ms Potential loss of one half-cycle due to fault current sense of half-cycles only

-4 ms Time required to open a sluggish circuit breaker

≤10 ms Maximum integration time that could be allowed

8 ms Value of integration time that accommodates component tolerances and other variables

Ct=

1× T

V

(5)

Where T=integration time

V=threshold voltage

I=average fault current into Ct

I=

120VAC(rms)

RB

×

RN

RG + RN

heavy fault

current generated

(swamps ITH)

portion of

fault current

shunted

around GFI

×

1 turn

1000 turns

1

× 2×

0.91

(6)

current

division of

input sense

transformer

Ct charging

on half-

cycles only

rms to

average

conversion

therefore:

120

Ct = 500

0.4

× 1.6+0.4 ×

1

1000

×

1

2

×

0.91

Ct = 0.01μF

17.5

× 0.0008

(7)

UTC UNISONIC TECHNOLOGIES CO., LTD. 6

QW-R122-007,A

Share Link: