UNDERVOLTAGE RELAY
UNDERVOLTAGE RELAY
(OP)
Why sometimes it is preferred to use instantaneous undervoltage relay with a time delay one in bus protection?
Elecme
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
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RE: UNDERVOLTAGE RELAY
It is common to use time delay on undervoltage relays to prevent undesirable operation on short term events.
RE: UNDERVOLTAGE RELAY
RE: UNDERVOLTAGE RELAY
Elecme, is the intent of your question to compare
RE: UNDERVOLTAGE RELAY
"A time delay relay is normally used to enable it to ride through momentary dips, thus preventing nuisance operation. An instantaneous undervoltage relay with its contact connected in series with the time-delay undervoltage relay contacts may also be used to provide a fast reset time, thus preventing the inertia (overtravel) of the time delay rely from tripping the circuit"
Can someone elaborate on this.
Busbar,
Can you mention some applications in which the 4
chatrctresitics of the under voltage realy applied.
Elecme
RE: UNDERVOLTAGE RELAY
There are several application papers and instruction books for Basler undervotage relays at: http://www.basler.com/php/download_page.php?section=protect#BE127
RE: UNDERVOLTAGE RELAY
The situation is not the same when you use an instantaneous relay with on/off action and a definite delay timer, as there is no overtravel and instantaneous reset of the timer.
Of course, this only applies with electromechanical relays.