Fan Amperage

Definition: What is Ampere?

Electrical energy can be thought of as a river. Just as different amounts of water can flow in a riverbed, a cable carries amounts of current of different magnitudes. The amount of current in a current flow is called this amperage. The physical unit is called the ampere and is indicated with the unit sign A. It is named after the French physicist André-Marie Ampère. In Germany, conventional lines are designed for a maximum of 16 amperes. Fuses prevent short circuits. The units amperes, volts and watts are not detached from each other, because power, voltage and strength are directly related.

Practical example: laptop power supply

On laptop power supplies, ampere ratings indicate the maximum amount of current that can flow through the power supply. For example, if a laptop requires 1.8 amps, you must never connect it to a power supply with a maximum of 1.6 amps. This is because the device will then try to draw too much current. The power supply can burn out and also damage the laptop.

How is it measured in amperes?

An ammeter, more commonly known as a current meter, is used to measure the current. To do this, the current must flow through the meter, so it must be connected to the circuit in series. This actually makes it necessary to disconnect the circuit. To avoid this complex procedure, indirect methods determine the current strength, for example, via the generated magnetic field. Attention must be paid to the type of current and the setting of the correct measuring range.

Watt: The relationship between ampere and power

Watt is the unit of electrical power. It indicates the work done by a device in a certain time. A normal power supply is rated at a maximum of 16 amps. This is converted to a maximum power of this circuit of 3,520 watts. If too many devices are connected at the same time, the current is too high. This triggers the fuse. The fan with the power of 2,000 watts generates – at the standard value of 230 volts – a current flow of 8.7 amperes. If an identical device were to run in parallel in the circuit, the maximum of 16 amps would be exceeded. Consequently, the device power cumulates and causes the current to increase.

Volt: The relationship between amperes and voltage

The unit of electrical voltage is called the volt. If amperes indicate the number of flowing electrons, volts stand for the energy they transport. In Europe, a voltage of 230 volts is applied in household networks. If the voltage of a circuit is lower, the maximum amperage also decreases. A fan with an output of 2,000 watts would not be allowed to be connected to a network with a voltage of 120 volts, as is common in the USA. This is because it would need 16.7 amps for this power.

The watt-ampere-volt formula: This is how easy it is to calculate the power

Because power, voltage and current are mutually dependent, they can be easily converted into each other. You can imagine the reciprocal relationship as a triangle. This results in the three formulas:

Ampere = Watt / Volt
Watt = Volt x Ampere
Volt = Watt / Ampere

Attention abroad: Pay attention to the voltage

In non-European countries, the voltage provided in the power grids may differ from the 230 volts that are usual here. In Japan about 100 volts are standard, in the USA 120 volts. This has a direct effect on the amperage required. To find out what amperage a device produces, divide the volts by the watts. Voltage converters fix the problem. Nowadays, many devices have the ability to manually adjust the voltage.

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Hello, since I want to build a fan for my external hard drive at the bottom of the case, I thought about running this fan directly from the power supply of the external hard drive. The power supply of the disk delivers 12V and 1,5 A at the output… The fan can be operated with 12 V but the nominal current is only 0,2A. Here are some short details of the fan which are given: Mains connection: 3-pin plug Operating voltage: 4 – 14 V Rated current: 0.2 A Energy consumption: 2.4 W Now my question: Whether it would be harmful or fatal to operate a fan or any electrical device with more amps than is specified on the website of the dealer / manufacturer. Because I would be about 1.3A above the rated current which was specified. Many thanks & best regards. TFlash

6 replies

Topnutzer in the topic Electronics if the fan is supplied with 12V it also takes only the specified power, no matter how strong the power supply is. Bad would be if you run it with more than 14V. Topnutzer im Thema Elektronik Whether the power supply provides 0,2 Ampere or 12000 Ampere providesdoesn’t matter at all, as long as the voltage of the devices is the same and the minimum current from the side of the supply unit is available. I have no problem with my municipal water supplier providing more water supply than I need. The water pressure, on the other hand (here compared to the voltage), must be kept within certain limits so that the water arrives on the one hand and the pipes do not burst on the other. The ancient Romans had already mastered this. Oh, the fan only draws as much current as it needs. It would be worse if the voltage was higher. So no problem to run it like this 😉 Hi! First of all the question is: Why do you want to attach a fan to your external hard drive? External hard disks, just like internal ones, don’t need a fan. Fans are only needed for components that can overheat, like the power supply or the CPU. Secondly, I don’t completely agree with the previous speakers. A power supply that provides a stable output voltage (about 12V) has a built-in voltage regulator that can only handle a certain amount of power or amps (usually 1 – 1.5). If you connect devices to such a power supply that require a higher power (more amps), then the voltage regulator overheats and burns out. Greetings Topnutzer in the topic Energy The specification 1,5 Ampere at the power supply only says, which maximum current the power supply brings, without the voltage of 12 Volt collapsing. If the fan draws 0.2 A, then there is still 1.3 A left for the hard disk.