Benign Environment DC-DC Converters ≤100 Watt H Series
Edition 4/4.99
13/19
MELCHER
The Power Partners.
Table 14: Isolation
Characteristic Input to Input to Output Output Unit
case output to case to output
Electric Required according to 1.5 3.0 1 0.5 - kVrms
strength IEC/EN 60950 2.1 4.2 1 0.7 - kV DC
test voltage Actual factory test 1 s 2.8 5.6 1 1.4 0.3
AC test voltage equivalent 2.0 4.0 1 1.0 0.2 kVrms
to actual factory test
Insulation resistance at 500 V DC >300 >300 >300 >100 2 MΩ
1In accordance with IEC/EN 60950 only subassemblies are tested in factory with this voltage.
2Tested at 300 V DC.
For creepage distances and clearances refer to:
Technical Information: Safety.
Cleaning Agents
In order to avoid possible damage, any penetration of liq-
uids (e.g. cleaning fluids) is to be prevented, since the
power supplies are not hermetically sealed.
Standards and approvals
12H…48H DC-DC converters correspond to class I equip-
ment. All types are UL recognized according to UL 1950, UL
recognized for Canada to CAN/CSA C22.2 No. 950-95 and
LGA approved to IEC/EN 60950 standards.
The units have been evaluated for:
•Building in
•Supplementary insulation between input and case and
double or reinforced insulation between input and out-
put, based on 250 V AC and 400 V DC
•Operational insulation between output(s) and case
•Operational insulation between the outputs
•The use in a pollution degree 2 environment
•Connecting the input to a primary or secondary circuit
with a maximum transient rating of 2500 V.
The DC-DC converters are subject to manufacturing sur-
veillance in accordance with the above mentioned UL,
CSA, EN and with ISO 9001 standards.
Protection Degree
Condition: Female connector fitted to the unit.
IP 40: All units, except those with option D or V with
potentiometer.
IP 20: All units fitted with option D or V with potentiometer.
Isolation
The electric strength test is performed as a factory test in
accordance with IEC/EN 60950 and UL 1950 and should
not be repeated in the field. Melcher will not honour any
guarantee/warranty claims resulting from electric strength
field tests.
Installation Instructions
The H series DC-DC converters are components, intended
exclusively for inclusion within other equipment by an in-
dustrial assembly operation or by professional installers.
Installation must strictly follow the national safety regula-
tions in compliance with the enclosure, mounting, creep-
age, clearance, casualty, markings and segregation re-
quirements of the end-use application. See also:
Technical
Information: Installation and Application.
Connection to the system shall be made via the female con-
nector H11 (see:
Accessories
)
.
Other installation methods
may not meet the safety requirements.
All DC-DC converters are provided with pin no. 26 ( ),
which is reliably connected with their case. For safety rea-
sons it is essential to connect this pin with the protective
earth of the supply system if required in:
Safety of operator
accessible output circuit
.
Ensure that a unit failure (e.g. by an internal short-circuit)
does not result in a hazardous condition. See also:
Safety
of operator accessible output circuit.
To prevent excessive current flowing into the unit (e.g. by
an internal short-circuit), an external fuse suitable for the
application and in compliance with the local requirements
should be installed in the wiring to one or both input pins
(no. 29 and/or no. 32). See also:
Input Fuse
.
Important: Whenever the inhibit function is not in use,
pin no. 2 (i) should be connected to pin no. 23 (Vo1–) to
enable the output(s).
Do not open the modules, or guarantee will be invali-
dated.
Make sure that there is sufficient air flow possible for con-
vection cooling. This should be verified by measuring the
case temperature when the unit is installed and operated in
the end-use application. The maximum specified case tem-
perature
T
C max shall not be exceeded. See also:
Thermal
Considerations.
If the end-product is to be UL certified, the temperature of
the main isolation transformer should be evaluated as part
of the end-product investigation.