1 generator frequency (rotational speed) oscillation: In general, the frequency oscillation ratio voltage, current oscillation range is small, but the impact is relatively large, resulting in ups in frequent switching and abnormal working conditions. Frequency oscillation generally in ± 5%%, the generator set due to the regular load and small, resulting in its work also suddenly strong and weak, the unit vibration intensified, accelerated mechanical wear, even the mechanical damage. One of the most obvious characteristics of frequency oscillation, i. e. Diesel engine working noise is a regular and small, so it must arouse high attention.
2UPS work is not normal: air conditioner compressor start-up and elevator fluctuation can cause the generator to occur ± 5HZ frequency drift, resulting ups frequent switching, when the frequency and voltage oscillation changes beyond the UPS input range of work, UPS by the battery power, and the generator in the absence of UPS load back to normal, then ups and automatically put into the staggered. Frequency drift affects the normal operation of ups two aspects:
① cannot bypass. In the frequency and voltage of the bypass power supply, the UPS inverter output tracks the bypass power supply, the inverter power supply and the bypass power lock phase, synchronous. When the bypass power supply is provided by the generator, the frequency changes rapidly, when the frequency changes exceed the pre-set limit value, the frequency change of the inverter can not follow the frequency of the bypass power supply. The static bypass switch will prohibit switching to the bypass (in this case, it is possible to cause the inverter to over-current and short-circuit). In the case of the bypass power frequency, the UPS will only emit a warning warning, and the inverter continues to supply the power to the load.
② battery life shortens. The previous mention of instantaneous large load fluctuations may cause the generator frequency to generate ± 5Hz drift, which will lead to SCR (thyristor) rectifier drive signal and input AC power loss synchronization, resulting in the rectifier shut down. When the rectifier restarts into the normal work, UPS to battery power, so excessive discharge cycle, will significantly shorten battery life, more serious situation will be the battery energy all shining, interrupt the power output.