- Application Scope
The TVR2000 series three-phase power monitor is mainly used in circuits with three-phase AC 50/60Hz and rated voltage of 80~690V. It provides relay protection for three-phase voltage imbalance, phase loss, reverse phase, and high or low power supply voltage of the three-phase motor input power. The protector should be wired according to the provided diagram, generally sampling the power supply side of the three-phase power. When the three-phase power supply is normal, the relay is energized, the normally open contact (NO) is closed, the normally closed contact (NC) is open, and the green LED lights up. When one or more abnormalities occur in the power supply, the relay is released, the normally open contact (NO) is opened, and the normally closed contact (NC) is closed. The green LED turns off, and the corresponding fault LED lights up.
- Protection Function Explanation
- Three-phase voltage imbalance and phase loss protection: Voltage imbalance refers to excessive negative-sequence components. In general, a 1% voltage imbalance can cause a 3% to 11% phase current imbalance. The negative-sequence component does not contribute to work but is converted into heat. Therefore, severe power voltage imbalance can cause the motor to overheat and burn out. At a voltage imbalance rate higher than 9±1.5%, the protector will operate (delay time < 1.5 seconds). It will automatically recover when the imbalance rate is below 7±1.5%.
- Phase reversal protection: When L1, L2, and L3 are correctly connected, the normal (NORMAL) green LED is lit, and the relay is energized. If the phase sequence is incorrect, the normal (NORMAL) green LED does not light up, and the phase reversal (REVERSAL) red LED lights up. As long as any two phases of L1, L2, and L3 are exchanged, the product can recognize the correct phase sequence and work normally. It has a function to prevent incorrect connections.
- Over-voltage and under-voltage protection: Three-phase induction motors operate most efficiently at the rated voltage. When the power supply voltage is too high, it increases the no-load excitation current, causing the motor efficiency to decrease and generate heat. When the voltage is too low, the output power of the motor decreases, causing overload, and in severe cases, motor stall. The range of over-voltage and under-voltage protection should not be set too low; otherwise, frequent protection operations may occur due to fluctuations in grid voltage. When the average voltage of the grid is too low or too high, the under/over-voltage (UN/OV VOLTAGE) yellow LED lights up. At this time, the relay does not release. Only when the voltage is continuously low or high for more than 8 seconds, the product recognizes it as an under-voltage or over-voltage fault, and the relay is released, and the normal (NORMAL) green LED turns off.