UPS power supply equipped with precision medical equipment Case Study(section 2)

 

2.UPS power load

The nominal capacity of UPS is its apparent power, in fact, UPS power load is usually non-linear load, which varies with the load factor of change in power, UPS power supply if the output characteristic is not good, the output voltage will produce fall, voltage stability decreases, the influence of load safety. So determining the size of the UPS power capacity should be considered in the capacity of UPS with non-linear loads, ie, according to UPS power supply provided by the rated power and power factor to determine the actual load capacity, to avoid overloading the UPS power because, while not working normal or damaged UPS power inverter. That is the rated output power 1KVA UPS power 1KVA does not necessarily drive the load. In order to extend the life of UPS, UPS power not long in running at full load. Backup UPS power supply generally select 60% to 70% of rated power load, line UPS power generally select 70% to 80% of rated power load, while the UPS power should not be excessively long period of running under light load conditions. Battery life is mainly affected by factors affecting the load size, battery capacity, ambient temperature, battery discharge cut-off voltage, the general formula to calculate UPS battery power supply time is T = V * AH * N * PF / W. Wherein T is a battery power supply time, V is the battery voltage, AH battery capacity is fixed, PF is the power factor UPS output power, W is the load power. Such as the battery voltage CT in our hospital is equipped with UPS power supply of 12V, freeze capacity of 100AH, power storage quantity of 64, because the power of 0.7, load power is 40KW, then its power supply time was T = 12 * 100 * 64 * 0.7 / 40000 = 1.344h about 80min, ie after power supply can be maintained for about 80min.

3. Proper use of power to the host of UPS

Before using the random use of UPS should read the instructions carefully. UPS uninterruptible power supplysuitable for long-term work, not every day or frequently switch machines. Load power is really necessary, you can switch between the UPS series air power output and load, air switch to disconnect the load power is turned off. Regularly (six months) of  UPS uninterruptible power supply  to do a job cleaning dust to prevent dust from entering the chassis affect the electronics cooling, and damage to electronic devices. Should regularly check and replace the UPS power supply cooling fan and large-capacity capacitor.

4.UPS Power Battery Maintenance

Because UPS power supply China using a maintenance-free battery, each 12V, basically works in series, typically ranging from a few to dozens of series. As long as a battery resistance increase or damaged, the entire group according to the design capacity of the battery can not supply, it may cause blackouts. Therefore, it is necessary periodic inspection and maintenance batteries.

4.1 UPS replacement battery power or new purchase of a new battery is fully charged before first use UPS power supply from production due to the user to install and use, requires a period of time, this time, the battery due to self-discharge caused by reduction of capacity, reach The nominal delay time, in order to ensure normal power supply, must use products that require manual charging when used in the initial hours.

4.2 ambient temperature using the battery should pay attention to the ambient temperature, the battery should normally be used between 0 ℃ ~ 30 ℃ ambient temperature. High temperature will shorten the battery life of sealed maintenance-free battery, when the ambient temperature exceeds 25 ℃, the temperature is increased by 10 ℃, the battery life will be shortened by half. Temperature is too low, the battery capacity of the actual release will also be greatly reduced.

4.3 long battery state of charge, the internal resistance increases or permanent damage therefore, avoid long-term battery in the "float" status, for those areas rarely a prolonged power outage UPS power supply must be running every 3 months to go artificially discharged once, turn off the AC input power supply UPS, UPS power supply in battery power mode, let the battery discharge current ≥0.1A.

4.4 should avoid prolonged battery deep discharge or a small current through the battery discharge when the battery low current discharge, as from the end of the reservoir is larger than the voltage drop is slow current, so when the UPS power protection shutdown, battery power has actually been discharge, causing battery failure or shortened life expectancy. If the battery deep discharge will affect its life, when the battery discharge 8h ~ 12h time it normally takes to charge the battery charged.

4.5 regularly checked at regular intervals (six months) Check batteries in each battery terminal voltage and capacity between each battery terminal voltage does not exceed 1V exceeds 1V on the need for maintenance, which uses equilibrium constant voltage limiting 0.5A charge or replace This battery. Need battery pack 4a ~ 5a replacement after the whole group, to ensure the normal use of UPS.

4.3 long battery state of charge, the internal resistance increases or permanent damage therefore, avoid long-term battery in the "float" status, for those areas rarely a prolonged power outage UPS power supply must be running every 3 months to go artificially discharged once, turn off the AC input power supply UPS, UPS power supply in battery power mode, let the battery discharge current ≥0.1A.

4.4 should avoid prolonged battery deep discharge or a small current through the battery discharge when the battery low current discharge, as from the end of the reservoir is larger than the voltage drop is slow current, so when the UPS power protection shutdown, battery power has actually been discharge, causing battery failure or shortened life expectancy. If the battery deep discharge will affect its life, when the battery discharge 8h ~ 12h time it normally takes to charge the battery charged.

4.5 regularly checked at regular intervals (six months) Check batteries in each battery terminal voltage and capacity between each battery terminal voltage does not exceed 1V exceeds 1V on the need for maintenance, which uses equilibrium constant voltage limiting 0.5A charge or replace This battery. Need battery pack 4a ~ 5a replacement after the whole group, to ensure the normal use of UPS.