Switching interrupters

Haure et al. (1989) also undertook experiments in which the liquid flow rate was periodically reduced rather than interrupted. Switching between time-average liquid velocities of 4.0 and 1.2 mm/s at s = 0.5 resulted in about a 10% increase in the time-average rate of SO2 oxidation over steady state. The rate improvement was independent of r over the 2 to 60 min range explored. This is considerably less than the increase when flow interruption is utilized. 

Interrupter switch. (Over 600 volts, nominal.) A switch capable of making, carrying, and interrupting specified currents. 

Switching devices. (Over 600 volts, nominal.) Devices designed to close and/or open one or more electric circuits. Included in this category are circuit breakers, cutouts, disconnecting (or isolating) switches, disconnecting means, and interrupter switches. 

Metal-Enclosed Load Interrupter Switch and Fuse Switchgear. This consists of fused load interrupter switches, bare or insulated bus and connections, power fuses, instruments for control, and control wiring and accessories. Both stationary and removable interrupter switches and power fuses are used. 

Testing section by section can be continued in each direction from the temporary CP location until the changes in the observed currents and potentials as the current interrupter switches on and off are no longer large enough to result in accurate data. The limits of the area that can be maintained above the protected criterion of -0.85 V or better can be established at this same time. 

Line Starters and Combination Starters A line starter consists of a contactor (motor-starting switch) and motor-overload relays, (Contactors are capable of canving and interrupting normal motor-starting and -running currents they are not, hovv ever, normally capable of interrupting short-circuit currents. They must be backed up by fuses or a circuit breaker for this function,... 

FIG. 29-5 Siiiiplificd schciiiatic dia raiii of a coiiilunation line starter with a circuit lirciLker as the fault interrupter and disconnect. Alternative fuses and disconnect switch are shown as siilistitiites for the circuit lirciLker,... 

TTiis is a severe duty for the switching contactors as they have to endure repeated arcing of the interrupting contacts every time they make or break. (Select only AC-4 duty contactors see Section 12.10.)... 

With the availability of 3.3 and 6.6 kV vacuum contactors the control of HT motors up to 6.6 kV systems has now become easier and economical, compact and even more reliable. For 11 kV. systems, vacuum as well as SF (Sulphur hexafluoride) breakers can be used. The HT motor s switching and protection through a vacuum contactor provides a replica of an LT system. The earlier practice of using an HT OCB, MOCB, or an air blast circuit breaker for the interruption of an HT circuit is now a concept of the past. 

The bus system of a switchgear assembly, its interconnecting links and wires are the protected type components, whereas an interrupter (breaker, switch or a fuse) may be a protecting or protected type, depending upon their application and location in the circuit. A contactor and an OCR are therefore protected devices in the same context, for they provide no short-time protection. A protecting device may become protected when it is also provided with a back-up protection. 

Thus, only three of the five interrupting devices can be switched at a time as required without causing a parallel operation between any of the two incomers. 

The schemes are logical and simple and have been drawn, to ensure that no two supply sources can ever be switched in parallel. The scheme prevents to switch an interrupter, that may cause it to operate in parallel with another, unless the first source is opened first. This is illustrated in the following schemes ... 

The logic is the same as above. In the trip circuit of each interrupter is wired the NO contacts of the other two interrupters. Obviously only two of the three interrupters can be switched at a time. 

The 2NO contacts of the limit switch are wired in series with the closing coil of the interrupter (Figure 13.45). As soon as the spring is fully charged these contacts change over to NC and the closing coil circuit gets ready to clo.se. 

To close or trip the interrupter locally or retnotely a breaker control switch is also wired with the closing and the shunt trip coils of the interrupter, as shown in Figure... 

Interrupting devices - switches, breakers, MCCBs, power contactors and fuses... 

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