Softstarters
A softstarter has different characteristics to the other starting methods. It has thyristors in the main circuit, and the motor voltage is regulated with a printed circuit board. The softstarter makes use of the fact that when the motor voltage is low during start, the starting current and starting torque is also low.
Internal faults in substation transformers
Transformers are subjected to many external electrical stresses from both upstream and downstream that can lead directly to internal fault(s). The consequences of any failure can be very great in terms of damage as well as in terms of operating losses. This article explains three major internal fault types that can occur in MV/LV substation transformers.
The basics of synchronous machines
Synchronous machines can be used as generators or motors. They are of 3-phase construction, even though some special exceptions can be found. A bulk of the applications are within power ranges roughly varying from a megawatt level to several tenths (or even hundreds) of megawatts with rated voltages from 3 kV to 15 kV.
Amplifier Classes
Not all amplifiers are the same and there is a clear distinction made between the way their output stages are configured and operate. The main operating characteristics of an ideal amplifier are linearity, signal gain, efficiency and power output but in real world amplifiers there is always a trade off between these different characteristics.
Fundamental characteristics of circuit breaker
Apart from small circuit breakers which are very easily replaced, industrial circuit breakers are equipped with removable, i.e. exchangeable, overcurrent-trip relays. Moreover, in order to adapt a circuit breaker to the requirements of the circuit it controls, and to avoid the need to install over-sized cables, the trip relays are generally adjustable.
Buchholz relay on oil transformer with conservator
The Buchholz relay has two oil-filled chambers with floats and relays arranged vertically one over the other. If high eddy currents, local overheating, or partial discharges occur within the tank, bubbles of resultant gas rise to the top of the tank. These rise through the pipe between the tank and the conservator. As gas bubbles migrate along the pipe, they enter the Buchholz relay and rise into the top chamber.
Rudolf Diesel
Dr. Rudolf Diesel boarded “SS Dresden”, a cross-channel ferry, at Antwerp in September 1913. He was going to see the newest diesel engine factory of London. The famous engineer was invited as a guest of honor to the opening of that factory. He was traveling alone. After dinner Rudolf Diesel went to his cabin at about 10 p.m. and that was the last time anyone saw him alive. His cabin turned out to be absolutely empty next morning on September, 30. There were only his coat and hat left on the deck.