In an application, I use an industrial AC-DC power adapter, the meanwell GST160A15.
The power adapter gives 15V@144W maximum power.
I carefully read the datasheet, and it states that the power adapter has overvoltage protection, 105 ~ 135% of output voltage.
My question is, in case of fault, can the power adapter give out an hazardous voltage? With hazardous I refer standard convention for wet locations, 70V DC or 33 V r.m.s and 46.7 V peak
Electronic – Can a power adapter give out hazardous voltage
mainspower supplyswitch-mode-power-supply
Related Solutions
Most likely the switch controls how the mains input is rectified into the input bulk capacitors. This was common on older ATX power supplies as well, to use single design that can be used globally. Today the PFC stage at the input can handle larger input range automatically.
In the supply, there might be two 200V bulk capacitors for storing rectified mains. In the 230V position, the bridge rectifier is connected as a full bridge to the two series connected capacitors to effectively use them as a single 400V capacitor. Stored voltage is about 325V peak, or about 162V per capacitor. In the 115V position, the bridge rectifier is connected as a half bridge to a single capacitor, where positive mains cycle rectifies the 162V peak into one capacitor, and negative mains cycle rectifies the 162V peak into other capacitor. The total voltage over both capacitors would then be again 325V.
So if you use the switch in 230V position and feed in 115V, the input voltage is half what is needed and due to undervoltage it may not work at all or it might be so simple design that it just blindly tries to work but output halved as well. As this is not intended operation it may damage the parts.
Using it the other way, switch in 115V position but feeding in 230V will be much more dangerous and spectacular. The fuse might blow immediately, and if it does not, there will be a lot of overvoltage at the capacitors so they can heat up and vent up electrolytes as vapour after a while (seen this) or the capacitors may just explode outright.
Background (with a little speculation)
Inside the TV's switch mode power supply will be one or several Y capacitors that connect the internally produced DC voltages to either live or neutral. They are there to reduce the common mode noise produced by the high frequency switching transformer from affecting the DC outputs. Without the Y capacitors, all the internal DC rails will be wobbling up and down at 100 ish kHz due to inter-winding capacitive coupling between the flyback primary transformer and its various secondaries. The wobble will not be massive but could be around 1 volt p-p.
If this were not a TV, then there might be no real use for the flyback noise suppression capacitors but, consider this; the TV has to connect to an antenna of some sort and, you don't want the noisy internal 0 volts of the TV to be superimposing several volts peak-to-peak of 100 kHz onto your antenna or satellite input signal. You might be sharing the antenna system with other homes (say in an apartment building) so, the internal design of the TV has to accommodate this scenario. If using a satellite dish then it will be connected via long wires with high capacitance to ground and 100 kHz noise is going to cause some detriment somewhere to the received signal.
Infrared remote
The infrared remote receiver in the TV will be active all the time whenever the TV is plugged into a wall socket so it will be constantly looking for an infrared signal that is encoded as "ON". The infrared detection circuit will use high gain circuits that feed into a form of data slicer that gives a digital output so, how many bits of encoding are used to represent "ON" and how long will it take random noise (via a high gain infrared detection circuit) to erroneously reproduce the bit stream that represents "ON"?
I have had some experience here to draw on. A high-speed data link I designed (650 Mbits per second) when not connected to a valid signal would trigger approximately every millisecond or so to indicate it had received a correct frame ID and, about every minute or so it would find exactly the same frame header in exactly the right place hundreds of bits later on. It would then indicate that it had received a valid frame of data. Of course it hadn't (and we knew that) but, just like false alien transmissions that people rave about, the hardware told us differently. Just random numbers coinciding.
Tossing a coin
How many times would you have to toss a coin to get 16 heads in a row? The data stream was 650 Mbps and in 1 ms the data receiver would get 650 kbits (with one false positive) - so "tossing a coin" 650,000 times resulted in a good chance of seeing 16 consecutive heads. OK I can't remember whether it was 1 millisecond or 5 milliseconds but, the point is this; if you do the experiment enough times (and very quickly) the number of false positives will be huge!
What has this got to do with the question?
If the Y capacitors were connected to the neutral incoming AC lead, it would offer better noise reduction than if it were connected to live. Now clearly, the live and neutral wires can be interchanged so you could ideally choose to have Y capacitor noise reduction capacitors connected to the "earthier" of the incoming AC wires and, if this gives slightly better noise reduction on the infrared detection circuits then it might make a big difference in receiving a false "ON" demand every hour or so and detecting a false "ON" every month or year.
Best Answer
Under no-fault conditions that type of power supply can be assumed to produce 15 volts (plus or minus a small percentage due to build up of tolerances and temperature coefficients). If part of the the voltage regulation circuit failed it could produce a voltage significantly higher than 15 volts and this is where a lot of designs use an independent crow bar circuit to clamp the voltage to an avarage safe limit should a component in the main circuit fail.
I suspect that design has protection against single component fails and uses a crow-bar circuit (as do a lot of designs that are certified CE). Some designs don't but they rely on an extensive analysis of what can happen under single fault/failure conditions.
I expect that if you look in the product data sheet there will be some information about this. As to whether this power supply is suitable for the environment type you wish to use it, read the data sheet.