Ripple Current

What is ripple?

Just about every machine employs at least one power supply between the main voltage and the other components in the system. While many different factors can lead to a power supply failure, one of the most commonly discussed is ripple current in a system. But this mode of failure is not the most easily understood.  We receive a lot of questions about what ripple current is and what leads to its presence in a system.

To fully understand the damaging effects ripple current can cause, it is important to understand what ripple current is. Most power supply devices take the current we have coming into our buildings (AC voltage, alternating current) and convert it into an easily usable DC current. When this AC voltage is not converted properly into DC and still carries a residual alternating affect it is called ripple.

There are two main causes of ripple in a power supply: problems coming from the load side and problems coming from an internal component failure.

Ripple caused by component failure

Internal Failures in most power supplies are brought on by failing capacitors.  Many factors can play into premature capacitor failures such as excessive heat, age, low-quality manufacturing practices, etc. When power supplies are designed, capacitors are used on the input side in order to smooth the AC current and if they have failed this attribute is lost. This will in turn cause a ripple current that can damage other components in the system.

Ripple caused by load side failure

Excessive loads such as too many devices connected to the supply, can also play havoc on these smoothing capacitors. Ripple can be caused by unwanted AC currents coming from the load side, and in this situation more ripple means more heat that must be dissipated in the capacitor.  At a certain point this will cause a thermal runoff effect that will eventually cause the capacitor to fail, opening up the circuit. A failure such as this can range from simple to catastrophic and will most certainly result in the device needing to be rebuilt by the service center.

Knowing what caused a failure is key to recognizing how to prevent it. Power supplies are the often the first device between your incoming power and your machine. Therefor it is imperative you keep them protected. But if ripple current causes an issue in your facility call us! We will always be here to help.

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