rv4141 Fairchild Semiconductor, rv4141 Datasheet - Page 5

• Manufacturer Part Number: rv4141
• Description: Low Power Ground Fault Interrupt Controller
• Manufacturer: Fairchild Semiconductor

RV4141A
R
fier is its maximum of 200 µV, the trip current error is
±5.6%.
The SCR anode is directly connected to a solenoid or relay
coil. It can be tripped only when its anode is more positive
than its cathode. It must have a high dV/dt rating to ensure
that line noise (generated by electrically noisy appliances)
does not falsely trigger it. Also the SCR must have a gate
drive requirement less than 200 µA. C3 is a noise filter that
prevents high frequency line pulses from triggering the SCR.
The relay solenoid used should have a response time of 3 ms
or less to meet the UL 943 timing requirement.
Sense Transformers and Cores
The sense and ground/neutral transformer cores are usually
fabricated using high permeability laminated steel rings.
Their single turn primary is created by passing the line and
neutral wires through the center of its core. The secondary is
usually from 200 to 1500 turns.
Transformers may be obtained form Magnetic Metals, Inc.
(www.magmet.com)
Calculating the Values of R
Determine the nominal ground fault trip current requirement.
This will be typically 5 mA in North America (117V AC)
and 22 mA in the UK and Europe (220V AC). Determine the
REV. 1.0.6 6/30/05
SET
Line
is 1 M , R
Note:
1. Portions of this schematic are subject to U.S. patents 3,878,435 and Re. 30,678.
GFCI
SEC
Mov
is 45 and the V
Sense Transformer
5 Ring Steel Core
1:1000
R
470
SET
1.1 Meg
IN
R
SET
OS
and C2
of the sense ampli-
10 nF
Neutral
Phase
C1
Figure 1. GFI Application Circuit
1
2
3
4
RV4141A
Grounded Neutral
R
15K
TEST
1:200
1000 pF
C4
8
7
6
5
Press to
minimum delay time required to prevent nuisance tripping.
This will typically be 1 to 2 ms. The value of C2 required to
provide the desired delay time is:
where:
C2 is in nF
T is the desired delay time in ms.
The value of R
rent specification is:
where:
R
T is the time delay in ms
P is the period of the line frequency in ms
I
N is the number of sense transformer secondary turns.
This formula assumes an ideal sense transformer is used.
The calculated value of R
30% to when using a non-ideal transformer.
1 F 35V
FAULT
Test
SET
12 nF
+
C2
C
C2 = 6 x T
F
R
is in k
SET
is the desired ground fault trip current in mA RMS
=
X0103DA
TAG
SET
---------------------------------------------------------------
I
1N4004
Q1
FAULT
10 nF
C3
Latching Contacts
to meet the nominal ground fault trip cur-
Normally Closed
4.6 N
Solenoid
COS 180 T P
SET
may have to be changed up to
R
24K
1W
LINE
PRODUCT SPECIFICATION
65-4141A-03
R
0.4
N
R
1.6
Application
Not Part of
Resistance
G
Fault
20K
R
B
Load
5