clamp-on ammeters close to transformers, motors, relays, and contactors.
Ammeter Applications Ammeters are useful for troubleshooting various electrical components by indicating a change in electrical value. Many examples and troubleshooting charts found throughout this book. But here are two simple examples of ammeter applications. Three-phase motor The approximate load on a three-phase motor can be determined while the motor is running. To do this, clamp the ammeter around each of the three-phase conductors, one by one: ●
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If the ammeter shows the motor is drawing current close to its nameplate reading, this indicates the motor is fully loaded. If the ampere reading on each conductor is significantly less, then the motor is not carrying a full load. If the current measured with the ammeter is higher than the nameplate, when the motor is running at full speed and rated voltage, then the motor can be assumed to be overloaded.
Electric baseboard heater The nameplate will indicate the heater’s characteristics. Let’s assume that the nameplate indicates a 1000-W, single-phase, two-wire heating element operating at 240 A. If an ammeter reading, which is taken while the 4
