The torque of an electric power meter is directly influenced by the relative direction of the voltage and current in the meter. If the current direction of one coil is reversed, the torque will also reverse. This can cause the pointer to swing or even be damaged. To avoid this issue, the terminals of the power meter are typically marked with “*â€, “+â€, or “-†symbols. When connecting the meter, it’s essential to connect the “*†terminals of both the current and voltage coils to the same polarity. This ensures that the current flows consistently through both coils, from “+†to “-â€. This is known as the “generator end code†for proper wiring. Even when the power meter is correctly wired, there may still be cases where the pointer reverses. There are two main reasons for this. First, the load side might actually have a power source, causing the load to generate power instead of consuming it. Second, in three-phase power measurements, if the power factor (cosφ) is less than 0.5, the power meter may show a negative reading. In such cases, reversing the polarity of either the voltage or current coil can help obtain a positive value. The polarity switch can be used to adjust the reading accordingly, adding a negative sign before the measured value. Therefore, when measuring single-phase power, if the meter is reversed, you can simply reverse one of the coils and add a minus sign to the result. However, when measuring three-phase power, if one of the meters shows a negative reading, the total power should be calculated as the difference between the two readings. This requires careful attention to ensure accurate results and prevent errors in measurement. Fiber Optic Accessories,Fiber Optic Cable Protection Sleeve,fiber optic cable connectors,fiber patch cables,fiber adapter Guangzhou Jiqian Fiber Optic Cable Co.,ltd , https://www.jqopticcable.com