7 tips for UPS installation
Time of issue:2021-07-06
In the construction of weak current projects, UPS is set up to solve the uninterrupted power supply. UPS power installation is a more important link. Before installing the UPS, you need to consider the UPS input and output power distribution.
The three basic functions of UPS: voltage stabilization, filtering, uninterrupted.
When the mains power is supplied, it is the function of the voltage stabilizer and the filter to ensure the normal operation of the equipment; when the mains is interrupted, it can pass the DC power provided by its DC power supply part (battery pack, diesel generator, etc.) It is converted into perfect AC power for the load, and the switch from mains power to battery power is generally 0 time switch, so that the load equipment can keep running without feeling any change, and truly ensure the uninterrupted operation of the equipment.
UPS installation tips:
Generally, UPS manufacturers will provide users with complete and detailed UPS installation requirements and precautions. Only by meeting this requirement can the normal operation of the UPS power supply system be guaranteed. In actual application, the engineer can send the relevant parameters to the customer according to the actual situation of the UPS to be installed, so that the customer can construct according to this requirement. The following is an explanation one by one:
1. The fluctuation value of the input mains power provided by the user for the UPS is generally less than the nominal allowable mains fluctuation value of the UPS. For example, a certain type of UPS nominally allows the mains input voltage fluctuation to be 220V+20%, then this item can require the user The mains power fluctuates at +15%, which is conducive to the normal operation of UPS; the zero-to-ground voltage is generally required to be less than 1.5V without load, and less than 2V with full load. Engineers can also propose this value according to site conditions and load requirements.
2. In order to eliminate common-mode interference, UPS has added filter capacitors between zero and live wires to ground. There are currents between zero and fire and ground, which may cause unequal currents on the zero and live wires, which will trip the circuit breaker with leakage. Therefore, the UPS front stage and load circuit cannot be equipped with a circuit breaker with leakage protection to avoid accidental power failure of the UPS and its load. It should be pointed out here that the main purpose for users to configure UPS is for the safe operation of important equipment such as computers, not for the safety of personnel. Therefore, the live parts of the line such as sockets, circuit breakers, etc. should not be frequently plugged in, unplugged or switched on. Together.
3. In order to eliminate interference, the input neutral line of most UPSs is isolated from the output neutral line or passed through a choke, so the neutral line of the UPS output (ie load) cannot be connected to the input distribution when doing UPS power distribution. On the neutral busbar of the electricity. The user can connect the UPS output (load) neutral line to a single neutral line bar. Some brands of UPS have a direct connection between the input neutral line and the output neutral line inside the UPS, so the input neutral line and the output (load) neutral line can be connected to the same busbar.
4. The UPS input circuit breaker is designed to individually control the on and off of the UPS input power, so do not connect other electrical equipment to the lower port of the UPS input circuit breaker, so as not to affect the normal on and off of the UPS input power.
Here is a point. Some users require UPS to work on battery backup for a long time after the mains power failure. In this way, the capacity of the external long-delay battery provided by the UPS will be large. To ensure that this part of the external battery can be With sufficient charging current (usually 10% of the total AH of the external battery), the manufacturer will equip the UPS with an external long-delay battery charger. The AC input power of this charger must be turned on and off at the same time as the UPS input power. , To ensure that the external charger will charge the external battery when there is city power, and when the city power is off, the battery will immediately discharge to the UPS inverter through the charger. Therefore, the AC input power of this charger must be connected to the lower port of the same circuit breaker as the UPS input.
5. When selecting input and output circuit breakers for UPS, first of all, the nominal rated voltage of the circuit breaker must conform to the rated input and output voltage of the UPS. For example, single-in and single-out UPS can have single-pole (or N+1, or two-pole) ratings. A circuit breaker with a voltage of AC220V or 250V, and a three-pole (or N+3, or four-pole) circuit breaker with a rated voltage of AC380V or 415V can be selected for the three-in-three-out UPS. It should be noted that the rated breaking capacity of the circuit breaker ICU must meet the requirements of the UPS manufacturer. Generally, the small UPS is 10KA or 6KA, and the large and medium-sized UPS are required to be above 30KA.
6. The connection between the UPS and the external long-time battery should not be too long, otherwise the voltage drop on the battery connection will be too large. In addition, users often pay great attention to the ambient temperature and humidity of the UPS host. Placing the battery with the host can also provide a good working environment.
7. It is recommended that users set up separate power distribution boards (cabinet) for UPS and its loads to facilitate centralized and reliable control of UPS and its protected loads. This switchboard (cabinet) must comply with relevant national standards.