EnrgTech

Brushless motors Brushless motors are increasingly becoming popular and rapidly taking over the roles that were previously played by brushed motors. This can be attributed to the brushless motor’s mode of commutation. Unlike its brushed counterpart, the brushless motor is electronically commutated. This makes brushless motors very efficient.       It also makes them more durable owing to the fact it does not have brushes that wear out over time leading to poor contact and arching. The efficiency of the brushless motor enables it to be made smaller, lighter and quieter for any given input. This has consequently increased their popularity in HVAC, automotive among other sectors. Brushless motors too have their downside.   Electronic  commutation requires controlling circuits that will ensure precise timing of the coil energization which is critical for accurate speed and torque control.  Precise timing also ensures that the motor run...

What are low voltage circuit breakers? The answer to this question is unwittingly simple. Low voltage  circuit breakers  are circuit breakers whose voltage threshold are 1000V. All circuit breakers that operate at voltages below 1000V are known as low voltage circuit breakers. The opposite is true for high voltage circuit breakers. Low voltage circuit breakers come in different types and are manufactured by numerous manufacturers. Types of low voltage circuit breakers Low voltage can be classified based on numerous characteristics. There is no standardized way to classify circuit breakers. To give you an insight into their various characteristics, we will classify them based on three of them: Sensing circuit Construction Medium used to extinguish the arc Sensing circuit There are two ways low voltage circuit breakers sense voltage, thermal and magnetic sensing. In thermal sensing, the circuit breaker uses a heating element to sense the heat produced by cir...

Brushes Brushes are devices that conduct current between stationary wires and moving parts. They are sliding contacts that are used to transmit current from a static to a rotating part of a motor hence ensuring a spark-free commutation. They form a very critical elements of a motor where they conduct electrical current between stationary and the rotating wires of the motor. They are also found in generators where they play a similar role. They are available in five grades; Electrographitic brushes Carbongraphitic brushes Low Friction coefficient (LFC) Soft graphite brushes Bakelite Graphite (BG) Resin-bonded CG-MC-CA. Metal-graphite brushes Carbon brushes have three operating parameters as discussed below. Why are they used in DC motors? To be able to understand the role brushes play in motors, we first need to understand how  DC motors   work. DC motors are made up of three parts, the stator, rotor, and the brush system. The stator makes up the main body o...

From our homes to our offices Light-emitting diode (LED) is increasingly becoming the popular choice of lighting in both homes and commercial premises. This rapidly growing popularity is no surprise as LEDs have proven to be more efficient and long-lasting than conventional lighting technology. Companies that have already embraced the LED technology have reported that they consume approximately 48% lesser energy than before. Considering that the lighting forms 25.5% and 20%of the total energy costs incurred by commercial buildings in the US and UK respectively, such a margin of savings is a huge relief for owners of commercial buildings. HOW LEDs work Ordinary incandescent bulbs emit light when current passes through the metal filament contained in Tehran. LEDs, on the other hand, pass electrons through a semiconductor to produce light. LEDs have p-n junctions that emit light when suitable current is applied to these leads. The current will enable the electrons to...

Brushless DC motors From PCs to drones, the Brushless DC (BLDC) motor has become a preferred choice and it is for a good reason, BLDC motors are more efficient and exhibit higher power density than their brushed counterparts. BLDC motors have less wear and tear and allow for the deployment of lighter and less expensive motors in applications. This means they live longer, are more reliable and require less maintenance. They are also less noisy than brushed motors. However, designing  BLDC motors poses numerous challenges the major one being the delivery of optimum efficiency for a given performance point. Power loss in MOSFETS Typical BLDC motors have a three-phase stator that rotates the rotor through an electronic control scheme which incorporates a 3 phase inverter circuit. The inverter circuit continually switches currents in the stator windings in synchronization with the rotor position as ascertained by the Hall sensors. The magnetic flux generated in the stator the...