By Ben Stowe, “Sound & Lighting Guru”
If you’ve ever had noise in your system or malfunctioning equipment, you’ve probably had people tell you to get a power conditioner. With so many choices out there, it’s easy to become confused about which one to get. Maybe you already have one but really have no idea what it does. Maybe you just don’t have anything else pressing right now and you’re the curious type. Whatever your reasons for reading, this article will explain the reasons to consider a power conditioner and highlight the differences in a few types.
First, what is it conditioning? Power is power right? It shows up at a plug-in on the wall and nobody really knows how or why it gets there. Not exactly. The path power takes to our walls (and eventually our rigs) involves a lot of steps, starting at a power generation plant, then over high-voltage lines to a substation where the voltage is stepped down and sent on to the power lines you see around town, then to a smaller transformer outside the building where it is stepped down further to it’s utilization voltage. In the US, the voltage in your standard wall receptacle is 120 volts of alternating current (AC), and it is alternating at 60Hz. While we can change the voltage with a simple transformer (and almost always do inside of our equipment) the frequency is determined by the generation process and we have little control over that.
Along this journey our power is exposed to many potentially hazardous forces. Among these are surges or spikes (sometimes called transients), noise, sustained over or under voltages, and in a worst-case scenario, lightning. A notable point about noise and surges, is that according to NEMA (the National Electrical Manufacturer’s Association) most of it originates within the building where you are using the power. Common sources of this can be motors (compressors from refrigeration units are notorious), fluorescent lighting, and other device power supplies.
Worse yet, our equipment is increasingly vulnerable to these effects. This is largely due to the increased efficiency of the devices that allows them to operate on smaller voltages and currents (making noise and transients proportionately larger) and the increased number of devices placed onto a circuit board. In 1965 Gordon Moore, the founder of Intel, famously predicted that the number of transistors in an integrated circuit would double roughly every two-years. While modern computing was impossible to foresee in 1965, Moore’s prediction has largely held true until 2015. The particulars aren’t important, but the big picture is. More stuff now occupies a smaller space inside our circuits. The SPARC M7 chip boasts 10,000,000,000 transistors, a nearly incomprehensible number. This means reduced space between devices and conductors on a circuit board, which increases vulnerability.
The issue is significant enough that the 109th Congress attempted to address the economic effects and national security risk posed by surges and outages in HR423. The bill wasn’t passed, but the fact that this is on the radar of the good folks at Homeland Security helps us to understand that the potential problem is real. It’s not always readily apparent either. The materials used to fabricate chips can only withstand a certain number of repeated surges. The effect is cumulative and after a while the device fails to operate properly.
NEMA identifies several symptoms of surge damage as the following:
- Computer lock-ups or latch-ups
- Unexplainable data corruption
- Equipment shutdown
- Flickering lights
- Premature failure of electronic ballasts or printed circuit boards
A power conditioner should address these threats, but like almost everything in this world, they are not all built equally. There are a variety of designs with varying effectiveness. It can be difficult to determine which one to get based on the information presented to you. They all probably say “Power Conditioner” on the outside, and they are a black rack-mount box with receptacles on the back. However, it’s what’s on the inside that counts. There are several power “conditioners” that are really not much more than power “distribution” devices. They turn one receptacle into many, and that’s about the only useful thing they do. They may boast some basic surge suppression in the form of MOVs (Metal Oxide Varistors), but probably do little to prevent against sustained over-voltages or noise. Generally, the price tag can be a pretty good indicator. The less expensive units are less effective.
A good power conditioner will protect from transients by rapidly clamping or dissipating that voltage away from our equipment. It will also protect from sustained over and under voltages, and will have RFI and EMI filters to help eliminate noise carried on the AC line. Figure A shows a simple, low-cost power conditioner with basic MOV protection. Figure B shows a more professional model with more advanced protection circuitry.
Hopefully the information here helps you make a more educated decision about which power conditioner is right for your application. If not, I’d like to quote a friend of mine that is a jeweler when he offers advice to people like me who know very little about jewelry. He once told me, “If you don’t know what you’re buying, you’d better know who you’re buying it from”.