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Is it possible to use a normal transformer instead of the KNX power supply. There´s a big price difference. |
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It will not work good. I have tried it myself earlier by using a the secondary 29V output without choke on the old power supplies. Runtime it was working but it was impossible to download with ETS. Without the choke (that is built in to all KNX power supplies today) it will be a bad environment for communication. |
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Yes, you can use a standard 24V DC power supply, but you always need a choke beetween the power supply and the KNX bus, and the power supply must be protected against short-circuit or overload (to protect the choke itself). The normal voltage for a KNX device is in the range 21 to 29V. You should consider that using a 24V supply you increase the risk of the supply voltage drop below 21V at the end of the line. So I recommend using this type of power supply only for testing purpose, not for a real installation. But for testing purpose, ABB sells a 30mA KNX power supply (NTI/Z 28.30.1) for only 55€ (Eibmarkt.com). This device has also a LED that indicate output short-circuit or overload. |
