Delay tripping

The recloser is another overcurrent device that automatically trips and recloses a preset number of times to clear or isolate faults. The concept of reclosing is derived from the fact that most faults are of the temporary type and can be cleared by de-energizing the circuit for a short period. Reclosers can be set for a number of operation sequences depending on the action desired. These typically include instantaneous trip and reclose operation followed by a sequence of time-delayed trip operations prior to lockout of the recloser. The minimum pick-up for most reclosers is typically set to trip instantaneously at two times the current rating. 

High set instantaneous overcun-ent through the positive sequence network. An initial delay of a few cycles is introduced to avoid a trip during a start, whereas it will trip instantly on a phase fault, cable fault or a short-circuit. 

Short-circuit protection. To provide an instantaneous tripping on a short-circuit delay of, say, one or two cycles may be introduced into the tripping circuit to bypass any transient currents and avoid an unwanted trip. 

Bus voltage relay (Relay code 27) provides an impulse to the generator trip circuit as soon as normal supply is restored. The generator falls out of the circuit automatically after a pause of = 10-30 seconds, and the engine stops. The relay now also has a delayed feature as it had during the start, to allow a pause to the main supply in case the main supply fails quickly again. 

The motor protection relay, as discussed in Section 12.5, is generally provided with a delay feature to bypass these transients and delay the tripping by two or three cycles. 

Time-delay—An intentional time delay is inserted between the relay decision time and the initiation of the trip action. 

A simple Michelson interferometer. If we place two mirrors at the end of two orthogonal arms of length L oriented along the x and y directions, a beamsplitter plate at the origin of our coordinate system and send photons in both arms trough the beamsplitter. Photons that were sent simultaneously will return on the beamsplitter with a time delay which will depend on which arm they propagated in. The round trip time difference, measured at the beamsplitter location, between photons that went in the a -arm (a -beam) and photons that went in the y arm (y-beam) is... 

Alarms are used to alert operators of serious, and potentially hazardous, deviations in process conditions. Key instruments are fitted with switches and relays to operate audible and visual alarms on the control panels and annunciator panels. Where delay, or lack of response, by the operator is likely to lead to the rapid development of a hazardous situation, the instrument would be fitted with a trip system to take action automatically to avert the hazard such as shutting down pumps, closing valves, operating emergency systems. 

Explosives may be detonated electrically or nonelectrically. A nonelectric firing system will consist of a blasting cap, a length of time (safety) fuse or a firing device attached to the cap, and a means of activating the system match, fuse lighter, delay mechanism, or trip wire. The electric system requires an electric cap which has two wires attached, perhaps additional wire, and a battery or batteries to provide the current which activates the cap. 

The superposition principle allows us to assume just a single scatterer in the view of the radar. The transmitted signal hits this scatterer whose distance (we measure distance and time in the same units) from the (collocated) transmitter and receiver is r. Assume that the scatterer is stationary. The return signal will be a delayed version of the original, delayed by the total round trip time from the radar to the scatterer. Specifically the signal voltage at the antenna of the receiver is... 

In addition to these experiments, George Aghajanian proceeded to see if Thorazine would reverse LSD-induced performance impairment. At the time, Thorazine was still the most widely accepted medication for controlling bad trips. George found that it raised NF scores only slightly and did not shorten the overall duration of impairment. Surprisingly, Thorazine sometimes even delayed the final return of performance scores to baseline. 

This is not quite true. Whenever we start a pump, the starting torque required to get the pump spinning requires a surge of motor amps. To avoid tripping off the motor on high amps, there is a time delay built into the trip mechanism. This delay permits the amperage load to greatly exceed the FLA point, for up to 15 to 30 s. This is too brief a period in which to overheat the motor. 

Our home circuit breakers, or fuses, are, of course, trips to prevent overheating electric circuits or electric motors. The only difference is that at work, our electric circuit breakers have a built-in time delay. This is needed to allow the motor driver to overcome the starting torque inherent in most large pieces of rotating process equipment. 

The fact that the birds developed delayed neurotoxicity under laboratory conditions indicates that the lack of it in the field study was not due to an inability of this mutant to develop the neuropathy. "Early warning" tests for delayed neurotoxicity are lacking. The laboratory data suggest that serum enzymes like CK may be useful markers for organophosphate exposure. However the conditions of this test must be controlled. The increase of CK in all birds taken to Visalia, regardless of their exposure to DEP in the field, suggests that the rigor of the trip may have stressed the birds and increased CK levels. Plasma CK activity in humans is known to increase under stress, such as after heavy exercise (12). 

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