Avago Technologies ACPL-224-500E - Manual (Page 5)

AV02-4387EN 3 Avago Technologies
Common Terms
External Clearance
The shortest distance through air,
between conductive input and
output leads, measured in mm.
Refer to Figure 4.
Comparative Tracking Index (CTI)
Outer molding material charac-
terization in the presence of aque-
ous contaminants. The higher the
CTI value, the more resistant the
material is to electrical arc track-
ing. CTI is often used with creep-
age by safety agencies to deter-
mine working voltage.
External Creepage
The shortest distance along the
outside surface, between input
and output leads, measured in
mm. Refer to Figure 4.
Dielectric Insulation Voltage Withstand
Rating
The ability to withstand without
breakdown a 60 second appli-
cation of a defined dielectric insu-
lation voltage between input and
output leads.
Distance Through Insulation
Distance between the photo-
emitter and photodetector inside
optocoupler cavity (also called in-
ternal clearance). Refer to Figure 4.
Installation Class
I Equipment in closed systems
(e.g., telecom) protected
against over voltage with de-
vices such as diverters, filters,
capacitors, etc.
II Energy consuming equip ment
(e.g., appliances) supplied
through a fixed installation.
III Primarily equipment in fixed
installations (e.g., fixed indus-
trial equipment).
IV Primary supply level for indus-
trial factories.
Insulation
Operational - required for correct
equipment operation but not as a
protection against electric shock.
Basic - protects against electric
shock.
Supplementary - independently
applied to basic insulation to pro-
tect against shock in the event of
its failure.
Double - composed of both basic
and supplementary. Reinforced
- A single insulation system com-
posed of several layers (e.g., single
and supplementary).
Internal Clearance
See Distance Through Insulation.
Internal Creepage
The shortest border distance be-
tween two separate insulating ma-
terials measured between emitter
and detector.
Material Group (see Compara tive
Tracking Index)
I 600 < CTI
II 400 < CTI < 600
IIIa 175 < CTI < 400
IIIb 100 < CTI < 175
Partial Discharge
Electric discharge that partially
bridges the insulation between two
electrodes. Avago supports partial
discharge measurements per IEC/
EN/DIN EN 60747-5-2, a technique
developed to evaluate the integ-
rity of insulating materials. IEC/
EN/DIN EN 60747-5-2 philosophy
is that partial discharge testing
offers advantages over Dielec tric
Withstand Voltage testing, which
might adversely affect the insu-
lating material, and over through
insulation distance requirements
which not only increase manufac-
turing costs but also do not neces-
sarily result in acceptable insulat-
ing capability.
Pollution Degree
1 - Nonconductive pollution only.
2 - Only occasional, temporary
conductivity due to condensa-
tion.
3 - Frequent conductive pollu tion
due to condensation.
4 - Persistent conductive pollu tion
due to dust, rain or snow.
Rated Mains Voltage
Primary power voltage declared
by manufacturer. Used to catego-
rize optocoupler maximum allow-
able working voltage.
Insulation and Regulation