In some of the need to make sure that load constant electric applications, sometimes customers will find UPS high frequent DC BUS protection, or negative work protection, etc. Some customers will think that is the quality problem of the UPS accordingly. Behind, in fact, in most cases this is due to the class with motor load produced by the phenomenon. In industrial situations, the motor is a kind of main form of load. When the key links of industrial applications must have a high enough level of power protection, UPS and motor load match problem is a key factor.

 

   Usually UPS is designed to protect key IT, such equipment on the circuit structure is mainly based on the characteristics of the IT class equipment design. Such as the IT equipment is mainly the use of switching power supply, and the European Union's rules and regulations of more than 75 w with power factor correction equipment. So UPS with power factor correction are mainly with load, under normal circumstances the feature is a constant power load power factor is close to 1. In terms of high-power electrical equipment, and some old equipment in use, these devices are usually based on six pulse rectifier or 12 pulse rectifier technology, characterized by a constant power nonlinear rectifier load.

   Both switch power source with PFC, and pulse wave rectifier power supply, the power of the real part can only be positive, energy does not fill back to the utility, so pay more attention to in the design of the UPS is in the reliability of constant power loads, as well as those with nonlinear rectifier load harmonic control ability, as well as the voltage steady state accuracy and dynamic recovery, without special requirement has the ability of energy feedback. Especially after the UPS with a large number of intelligent design, often the energy from the load feedback to the dc bus of UPS is treated as a fault condition. So when the class with the electrical load, motor energy renewable electricity generation is easy to trigger the UPS protection conditions.