Surge Protection for Power Supply
OVERVIEW
Today’s increased reliance on very sensitive electronics makes surge protection an important topic for most industries. The Insurance Institute for Business & Home Safety study found that $26 billion dollars was lost due to non-lightning power surges. In addition, there are about 25 million lightning strikes in the US each year that cause between $650M to $1B in losses according to the Insurance Information Institute, State Farm©.
Power supplies are a key component of any UL 508A control panel (also known as an Industrial Control Panel or ICP). However, they are usually overlooked due to their limited cost in the overall system. The power supply is usually the main source of power for control circuits and Programmable Logic Controllers (PLC). Its failure causes complete equipment shutdown.
The evolution from transformer-based power supply to Switch Mode Power Supply (SMPS) increases the vulnerability of this device to electrical transients. As more solid-state components keep being added, now to remotely program and control the power supplies through RS232 or Ethernet, surge protection has become critical part for any electrical system.
This section will identify the UL 1449 5th Edition Surge Protective Device (SPD) to efficiently protection your equipment and increase its reliability.
Power Supply AC Input | Power Supply DC Output | Power Supply Communication I/O
Power Supply AC Input
The main AC incoming will be the primary location to protect the power supply against electrical surges. There can be a multitude of AC input voltages of power supplies ranging from 120Vac Single Phase up to 600Vac 3Phase. However, most of the power supplies will fall under 2 categories (2W+G and 3W+G). Based on the built-in withstand of the equipment, most of the power supplies can be protected using SPDs shown below :| Location | System | Surge Protector Model # | Link |
|---|---|---|---|
| AC Incoming Power | 120 to 240Vac (2W+G) | DS72US-240T/NN |
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| AC Incoming Power | 277 to 480Vac (2W+G) | DS42S-480 |
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| AC Incoming Power | 120 to 240Vac (3W+G) | DS73US-277Y/NN |
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| AC Incoming Power | 277up to 480Vac (3W+G) | DS74US-480D |
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Power Supply DC Output
The DC side of the power supply, especially when self-contained inside the UL 508A control cabinet, is one of the most overlooked parts in the system, leaving this part of the system vulnerable. The most common DC voltages would usually fall under two main voltages for unipolar and bi-polar power supplies, 24Vdc and 48Vdc.| Location | System | Surge Protector Model # | Link |
|---|---|---|---|
| DC Output Power | 24Vdc (2W+G) | DS220S-24DC |
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| DC Output Power | 48Vdc (2W+G) | DS230S-48DC |
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Power Supply Communication I/O
Power supplies have evolved and will become more sophisticated than they are now, the latest generations allow an end-user to remotely access the power supply. Besides getting expected Internet Of Things (IoT) power data (wattage, input/output voltage, input/output voltage current), the remote access also provides full control and programming of the actual power delivered to the equipment. This new technological achievement comes at an extra cost. The external communication circuit of the power supply presents new vulnerabilities to electrical surges. The main protocols presently used is RS232, through multiple interfaces : twisted-pair wire and serial connector.| Location | System | Surge Protector Model # | Link |
|---|---|---|---|
| Communication circuit | RS232 (1-pair wire) | DLA-12D3 |
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| Communication circuit | RS232 (9-pin Serial DD connector) | DD9-24V |
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| Communication circuit | RS232 (Ethernet / RJ45) | MJ8-CAT6A |
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Contact us to develop a surge mitigation solution for your application
Where to purchase Citel SPD's google
