Search results
Results from the WOW.Com Content Network
Simplified single line diagram of a single-phase transfer switch to select either 'city' (utility) power or local generator power 3-phase Intelligent transfer switch. A transfer switch is an electrical switch that switches a load between two sources. Some transfer switches are manual, in that an operator effects the transfer by throwing a ...
The longer the switch is on compared to the off periods, the higher the total power supplied to the load. The PWM switching frequency has to be much higher than what would affect the load (the device that uses the power), which is to say that the resultant waveform perceived by the load must be as smooth as possible.
A switch with both types of contact is called a changeover switch or double-throw switch. These may be "make-before-break" ("MBB" or shorting) which momentarily connects both circuits, or may be "break-before-make" ("BBM" or non-shorting) which interrupts one circuit before closing the other.
Pages for logged out editors learn more. Contributions; Talk; Changeover switch
The utilization of the binary properties of electrical switches to perform logic functions is the basic concept that underlies all electronic digital computer designs. Shannon's thesis became the foundation of practical digital circuit design when it became widely known among the electrical engineering community during and after World War II .
The uncontrolled timing of the changeover allows the peak motor current to be switched at any point on the wave. Figure 5 shows the changeover at 90 degrees. This is a worst-case scenario, peak current at changeover, creates a very high and fast transient. The central switch circuit prevents voltage escalation, as discussed above.
Switching circuit theory is the mathematical study of the properties of networks of idealized switches. Such networks may be strictly combinational logic, in which their output state is only a function of the present state of their inputs; or may also contain sequential elements, where the present state depends on the present state and past states; in that sense, sequential circuits are said ...
In a typical diverter switch, powerful springs are tensioned by a low power motor (motor drive unit, MDU), and then rapidly released to effect the tap changing operation. To reduce arcing at the contacts, the tap changer operates in a chamber filled with insulating transformer oil, or inside a vessel filled with pressurized SF 6 gas. Reactance ...