SIL 3 Power Supply System, 24Vdc, 50A/150A, Zone 2 / Div. 2


The Power Supply System type PSS1250 is an anodized aluminum 7"/9"/19” Rack unit (4U high) suitable to accept up to 2/6 plug-in Power Supply Modules type PSM1250 and 1 Overview module for diagnostic functions.
Each module is able to provide 24Vdc, 50 A output. Modules can be paralleled with load sharing circuits which distribute current load equally to each power supply module to increase reliability and reduce internal power dissipation.
The system accepts up to two independent AC power sources from 100 to 264 Vac.
Twelve configurations of 19” Rack Units are available with or without Hot Swapping and with or without Diagnostic.
Four configurations of 9” Rack Units are available with or without Hot Swapping and with or without Diagnostic.
Two configurations of 7” Rack Units are available with or without Hot Swapping.

Hot Swap Plug-ins:
When using racks configured for Hot Swapping, each PSM1250 power supply module can be placed in Zone 2/Div. 2 Hazardous Locations without having to monitor the hazardous gas presence and without disturbing Power Supply operations.
A plugin module (PSO1250) dedicated to monitoring all diagnostic functions of each power supply can be installed in the last rack slot; it can be operated through a front panel touch screen LCD color display which indicates input/output voltage, current and power, input line frequency, output current sharing percentage, internal temperature, alarm status.
RS485 Modbus output provides full diagnostic and status conditions.
PSO1250 presence or fault does not affect PSS1250 operation and functional safety application.
Overvoltage protection:
3 independent overvoltage protections: 1 voltage limiting loop at 30 Vdc and 1+1 crowbars at 30 Vdc.
Fully compliant with CE marking applicable requirements.
High load fuses breaking capability:
In case of short circuit on the load, the Power supply system delivers a very high peak current (about 800 Amp) for a duration of 0.5 ms. This characteristic ensures the instant breakage of the protective fuse or circuit breaker. Because of the very short peak current duration, other equipment connected to the load are not affected by the failure event and continue to operate without interruption.


• 2 universal AC Input Lines, 100 to 264 Vac (48 to 62 Hz).
• Power factor correction.
• Installation in Zone 2 / Div. 2 hazardous locations with hot swappable modules.
• EMC Compatibility to EN61000-6-2, EN61000-6-4.
• Highly regulated output of 24 Vdc, 50 A, for PSM1250 module.
• Under and over voltage alarm monitoring.
• 3 over voltage redundant protections.
• Redundant parallel connections with load sharing.
• Reduces Power dissipation (in parallel/redundant configuration) by replacing a Schottky diode with Mosfet Active Ideal Diode.
• 89% efficiency @230 Vac input and 24 Vdc output with full load.
• Fan speed control depending on ambient temperature and output power.
• High load fuse breaking capability without interrupting operations.
• 19” or 9” or 7" Rack unit, 4 U high, anodized aluminium, durable metal enclosure.
• Tropicalization for electronic components.
• Modbus RTU RS-485 diagnostic output.


100 to 264 Vac

SIL level

SS1250-2 - Power Supply System PSS1250, 24Vdc, 50A, 7

PSS1250-3-D - Power Supply System PSS1250, 24Vdc, 50A, 9

PSS1250-3 - Power Supply System PSS1250, 24Vdc, 50A, 9

PSS1250-7-D - Power Supply System PSS1250, 24Vdc, 50-100-150A, 19

PSS1250-7 - Power Supply System PSS1250, 24Vdc, 50-100-150A, 19


    DTS0412 PSS1250 data sheet (English) (PDF 4.38 MB)
    ISM0219PSS1250 instruction manual (PDF 14.43 MB)
    ISM0268General PSx1200 Series Safety Instruction Manual (PDF 931 KB)
    CRT128TÜV SIL Certificate Summary (PDF 4.78 MB)
    CRT130TÜV SIL Functional Safety Certificate (PDF 4.38 MB)
    CRT170ATEX Certificate n. BVS 15 ATEX E 006 X (PDF 2.59 MB)
    CRT173IECEx CoC for PSS1250, PSW1250, PSW1230 [link IECEx BVS 14.0006X] (PDF 793 KB)
    CRT317UL-cUL PSW1250, PSS1250 Ordinary (PDF 377 KB)
    CRT319UL-cUL PSW1250, PSS1250 Hazardous (PDF 459 KB)


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