Rugged Environment DC-DC Converters >100 Watt K Series
Edition 4/4.99
23/31
MELCHER
The Power Partners.
Due to high current values, all AK...FK units provide two in-
ternally parallel connected contacts for certain paths (pins
4/6, 8/10, 26/28 and 30/32 respectively). It is recommended
to connect load and supply to both female connector pins of
each path in order to keep the voltage drop across the con-
nector pins to an absolute minimum and to not overstress
the connector contacts if currents are higher than approx. 8
A. The connector contacts are rated 8 A over the whole
temperature range.
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.
Check for hazardous voltages before altering any connec-
tions.
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.
Cleaning Agents
In order to avoid possible damage, any penetration of
cleaning fluids is to be prevented, since the power supplies
are not hermetically sealed.
Isolation
The electric strength test is performed as factory test in ac-
cordance with IEC/EN 60950 and UL 1950 and should not
be repeated in the field. Melcher will not honour any guar-
antee claims resulting from electric strength field tests.
Table 13: Isolation
Characteristic Input to Input to Output to Output to Unit
case output case output
Electric Required according to AK, BK 1.0 2.0 1 0.5 - kVrms
strength IEC/EN 60950 1.4 2.8 1 0.7 - kV DC
test voltage CK, DK 1.5 3.0 1 0.5 - kVrms
EK, FK 2.1 4.2 1 0.7 - kV DC
Actual factory test 1 s AK, BK 2.8 5.6 1 1.4 0.14
AC test voltage equivalent CK, DK 2.0 4.0 1 1.0 0.1 kVrms
to actual factory test EK, FK
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 150 V DC.
For creepage distances and clearances refer to:
Technical
Information: Safety.
Standards and approvals
All DC-DC converters correspond to class I equipment.
They are UL recognized according to UL 1950, UL recog-
nized 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,
•Basic insulation between input and case and double or
reinforced insulation between input and output, based
on 150 V AC/DC (AK and BK) or 250 V AC and 400 V DC
(CK, DK, EK, FK),
•The use in a pollution degree 2 environment,
•Connecting the input to a primary or secondary circuit
which is subject to 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.Cleaning Agents
In order to avoid possible damage, any penetration of
cleaning fluids is to be prevented, since the power supplies
are not hermetically sealed.
Protection Degree
Condition: Female connector fitted to the unit.
IP 30: All units except those with option P, and except
those with option D or V with potentiometer.
IP 20: All units fitted with option P, or with option D or V with
potentiometer.