... 1. Safety certificate of approval for mining products. 2. Flame proof certificate 3. ISO 9001-2008 Mining explosion-proof and intrinsically safe ... load changes to achieve the required torque and improve the power factor under no-load situation. As the coal ... output frequency, current, power, motor speed, load rate, input and output torque, etc.Fault status displayOvervoltage, undervoltage, over load, ...