Harmonic is electric hazard which occurs by using inverter control. Although the inverter is highly efficient and energy-saving equipment, generation of harmonics is inevitable. Harmonic could also cause the other device’s malfunction. TMT series- a compact machine specialised for harmonic countermeasures. By using TMT, it is possible to check the power in harmonic countermeasures in real time. Harmonic countermeasures are effective even with only one load of the inverter. This technology aquired the patent in Japan. Tunnel site such as: shield machine / blower / dust collector / continuous belt conveyor Ground improvement site such as inverter control ultra high pressure pump