SamplexPower SEC-1212P, Owner'S Manual

10  |  SAMLEX AMERICA INC. 

In case (i) the fan fails or, (ii) the suction / discharge ventilation openings are blocked or, 
(iii) the ambient temperature ratings given in the specifications at Section 6 have been 
exceeded, temperature inside the unit will continue to rise. A second Temperature Sensor 
mounted on the Primary Heat Sink will shut down the output power if the Primary Heat 
Sink temperature rises to 105˚C ± 5˚C or above. The output power will be reset automati-
cally when the Primary Heat Sink cools down to 75˚C ± 5˚C or lower. 

3.3.3 Orientation of Top Cover Fitment – SEC-1223P/1235P/1235P-M

In SEC-1223P/1235P/1235P-M, the fan sucks cool air from the inlet slots located towards the 
front sides of the top cover (5, Fig 2.2 and 2.3) and the front side of the bottom housing 
(6, Figs 2.2 and 2.3). The air is discharged from the rear ventilation openings in the bottom 
housing behind the fan (8, Figs 2.2 and 2.3). For proper air flow path from the front to the 
rear, it is necessary that the top cover is fitted with the side ventilation slots (5, Fig 2.2 and 
2.3) oriented towards the front. To ensure this, 2 lanced tabs (7, Fig 2.2 and 2.3) are provided 
in the top cover that will slide into the corresponding slots in the rear side of the bottom 
housing. The top cover will not fit properly if the ventilation slots are facing towards the rear 
side because the lances tabs will interfere with the top edge of the front side of the bottom 
housing (there are no corresponding slots on the front side of the bottom housing)

3.3.4 Orientation of Top Cover Fitment – SEC-1212P

In SEC-1212P, there is no fan. Cooling is carried out by convection through the ventilation 
slots on the 2 sides of the top cover (5, Fig 2.1) and in the bottom housing (6, Fig 2.1). For 
improved cooling of the Primary Heat Sink through conduction, the air gap between the top 
surface of the Primary Heat Sink and the bottom surface of the top cover is filled by using 
a thermally conductive gap filler strip of soft, ceramic filled silicone elastomeric material. 
When the top cover is removed and fitted back, its orientation has to be such that the ther-
mally conductive gap filler strip gets positioned properly on top of the Primary Heat Sink. 
To ensure this, 2 lanced tabs (7, Fig 2.1) are provided in the top cover that will slide into the 
corresponding slots in the rear side of the bottom housing. The top cover will not fit prop-
erly if the 2 lanced tabs (7, Fig 2.1) are facing towards the front side of the bottom housing 
because the lances tabs will interfere with the top edge of the front side of the bottom 
housing (there are no corresponding slots on the front side of the bottom housing).

3.4   OVERLOAD / SHORT CIRCUIT PROTECTION 

3.4.1   Unit is used as a Power Supply without Battery Backup (12V Battery is 
not Connected to the Battery Terminals)

Refer to Fig 3.1 under Section 3

The SMPS Section is provided with Hiccup Mode of Overload and Short Circuit protections. 
Output load current from the SMPS is fed through a series connected, 0.1875 Ohm Load 
Sense Resistor inside the SMPS. Output load current produces voltage drop across the Load 
Sense Resistor. This voltage drop is proportional to the value of the load current. Protections 
are triggered based on the voltage drop sensed across the Load Sense Resistor as follows:

SECTION 3  

|  Description & Operation