Alltec Protection Systems Pvt. Ltd. Becomes the First Company in India to be Certified by Underwriters Laboratories in the Installation of Lightning Protection
When used to describe a specific type of long duration variation, refers to an rms decrease in the ac voltage, at the power frequency, for a period of time greater than 1 min. Typical values are 0.8 pu to 0.9 pu. (IEEE Std 1159)
Uninterruptible Power Supply (UPS)
An apparatus that supplies continuous power to a load, despite disturbances and outages in the mains. A UPS contains a bank of rechargeable batteries that supply power in the absence of acceptable supply voltage.
Updraft
An updraft is a small scale current of air with vertical motion. If there is enough moisture, then it may condense, forming a cumulus cloud which is the first step towards thunderstorm development.
Upward Flash
Lightning flash initiated by an upward leader from an earthed structure to a cloud. An upward flash consists of a first long stroke with or without multiple superimposed short strokes, which can be followed by subsequent short strokes possibly including further long strokes.
Utilization Voltage
The root-mean-square (rms) phase-to-phase or phase-to-neutral voltage at the line terminals of utilization equipment.
