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Why Do Amp Meters Fluctuate?

David Hill

Fluctuating power can cause worry and concern, especially when operating personal air crafts or boats. An amp meter, otherwise known as an ammeter, can display electrical malfunctions in the form of fluctuations, or have drops in the level of efficiency. Great care must be taken to correct problems with the wiring when an ammeter shows fluctuations.


Amp meters may fluctuate for several reasons.

Improper loads on the circuit can cause the contacts in electrical components to heat or warp open. The process of the contacts warping open then closing when cooling can cause the system to turn on and off, causing the ammeter to fluctuate. The overloading of the circuit and parts can cause serious damage or significant safety concerns when operating large personal crafts.

Alternator Switches

Poor connection between the alternator switches and the lines can cause fluctuations on the ammeter. When problems occur in the line, the regulator attempts to pull more current until it shut downs or resets, causing the ammeter and other system parts to turn on and off rapidly.

Heavy Loads

Changes in motor speeds or power used by hydraulic pumps may cause the electricity being pulled from the power source to spike, which can be reflected in the ammeter.

Alternator Belt

Tension problems, such as too much slack or overly tight fitting alternator belts can cause the motor to use varying amounts of power. Worn or stuck rotor brushes can contribute to changes in the electricity used and cause the amp meter to fluctuate.