Principle of Operating Electrical Devices - Coursework Example

Name Course Date Report: Principle of Operating Electrical Devices Principle of Operating Electrical Devices Introduction The term principle of operation denotes the basic mechanism in which a particular equipment (machine) conducts its designated function. Engineering research findings suggest that every machine’s unique functionality relies on its differential operating principle(s). Therefore, in order to understand a given machine’s functionality, one needs to understand the operating principle of that particular machine. Following the understanding, one can utilize a given machine effectively and efficiently. In this regard, this paper seeks to present a discussion that details the operating principle of several electric devices. These devices include 24V dc Relay, Submersible Pump, 230V ac Contactor, Rectifier (AC to DC), Circuit breaker (low voltage 400V ac), and Solenoid valve and ball valve. Contextual discussion 24Vdc Relay According to Pratumsuwan and Watcharin (2011) 24Vdc Relay consists of a solenoid, a reluctance iron yoke, an iron armature and contact sets [1]. The solenoid provides a hinge-position for the movable armature. The hinging links the armature to the contact sets. The armature is further held in its position by a spring. It is important to note that the hinge ensures continuous flow of current between the solenoid and the contact sets. In this case, it completes the circuit of a relay board. The passage of the direct current in the solenoid results in the generation of a magnetic field. The resultant field dictates the movement of the armature, whereby it prompts the breakage or connection of the circuit current. In other words, if the contact sets are intact (closed), the current de-energizes the solenoid. The de-energization prompts the separation of the contact sets. The vice versa occurs if the contact sets are ‘open’ and the solenoid is energized by a direct current [2]. However, in the absence of a direct electric current, gravitational force that is fostered by the spring returns the armature to a relaxed position. Furthermore, the uniqueness of a 24V dc Relay is provided by the addition of a diode on the solenoid. With regards to Gurevich (2005), the diode’s function is to dissolve the energy released by the subsiding magnetic field due to the deactivation of the circuit [3]. The absence of the diode results in the generation of a magnetic-induced voltage spike that damages the semiconductor components of a 24V dc Relay circuit. The diode is sometimes substituted by a snubber circuit. A snubber circuit entails the series connection of capacitors and resistors. Submersible Pump According to Takács (2009), submersible pumps are submerged in a vertical position under water and mechanically driven by an electric motor [4]. Therefore, the pump consists of a body pump and the driving motor. It is normally used to convey liquidated materials from under-the-ground to the surface. Basing on the liquidated materials, submersible pumps are divided into corrosive water pumps, sewage pumps, sand slurry pumps and clear water pumps. The usability of all types of submersible pumps depends on their vertical operating mechanism. Whereby, regardless of the evolutionary changes that have occurred over the past years, the operating principle of submersible pumps remains the same. As such, submersible pumps produce liquidated materials when the impeller is rotated [4]. The production speed depends on the intensity of the centrifugal force that is dictated by the rotational speed of the impeller. It is important to note that, kinetic energy of submersible pumps is lost in the diffuser. The diffuser represents the part of the pump where kinetic energy is converted to pressure energy. This explanation details the simplest operating principle of all types of submersible pumps. Contextually, there are other parts that are imperative to the operation of a submersible pump. For instance, the pump’s shaft connects to the protector (gas separator) at the pumps’ bottom base via mechanical coupling. The connection allows the intake of the liquidated materials by the pump using the ‘screen’ part [4]. The intake is followed by a series of lifting, whereby, materials are lifted in stages with the aid of bushings (radial bearings) distributed along the pump’s shaft. 230V ac Contactor Unlike relays that are used to handle low electrical voltage, contactors are used to handle high electrical voltage. Basing on Slade (2013), contactors’ operating principle is slightly sophisticated [5]. In the case of 230V ac contactor, the current’s passage in the solenoid (electromagnet) produces a magnetic field. The field induces the attraction of the contactor’s moving core. Initially, the solenoid draws a lot of current that increases its inductance and causes the core to interact with the solenoid. The core’s movement propels the flexibility of the movable contact sets. As a result, the solenoid’s electromagnetic force binds the movable and the fixed contact sets of the circuit [5], [6]. The de-energization of the solenoid induces the springs’ gravitational pull that retracts the core’s movement leading to the opening of the contacts. It is necessary to note that, this explanation represents the basic operating principle of many contactors. However, in 230V ac contactor, the solenoid is partly covered with a shading coil. The coil’s role is to delay the core-induced magnetic flux. The delay necessitates the ‘averaging-out’ of the magnetic field’s alternating pull, thereby preventing the double line frequency buzzing of the core. Alternatively, research shows that damages such as arching always accompany the opening and closing of the contact sets. In this regard, 230V ac contactors’ design consists of a tipping point apparatus that induces the quick opening and closing of the contact sets [6]. Although the quick opening and closing of the contact sets induce contact bounces that result in rapid unwarranted open-close cycles, modern designs have bifurcated contacts. The bifurcated contacts reduce the ‘bouncing-off’ and prevent arching. Rectifier (AC to DC) Rectifiers are electric devices that are used to convert alternating current (AC) to direct current (DC). They are variably constructed due to their differential usability. However, their construction relies on a singular principle of operation. Whereby, the current passes through the rectifier’s circuitry in one free direction. With respect to Liu, Bin, Navid and David (2007), this means that the flow of current in the opposite direction of the circuitry is nearly impossible [7] (see fig. 1). The rectifiers consist of diodes (semiconductors) that are important in dissolving the heat generated by the conduction of the electric current. Since diodes are ineffective in large rectifiers, such rectifiers are constructed with in-built heat sinks or cooling fins. Therefore, it is possible to deduce that rectifiers are paramount devices in electronic power supplies. Furthermore, the mechanical usability of the rectifiers in power supplies leads to the division of rectifiers into two main types. These types include the polyphase and synchronized alternating current rectifiers. The former constitutes of a rotating switch, which is coordinated with the fluctuations associated with alternating current. On the other hand, the latter uses a coordinated vibrating reed to transform alternating current’s single phased occurrence into direct current’s pulsating occurrence. Regardless of the mechanical operating mechanism, rectifier circuitries are broadly divided into two forms. They include single-phase and multi-phase circuitries [7]. The single-phase circuitries are used in domestic power supplies, while multi-phase circuitries are designed for industrial application and transmission of High Voltage Direct Current (HDVC). Fig 1: Demonstrates the conversion of 120V ac to 9V dc using a rectifier Circuit breaker (low voltage 400V ac) The circuit breaker operates when faulty conditions occur in a given circuitry. Low voltage circuitries rely on breaker enclosures. The detection of fault is characterized by the opening of the circuit breaker contact sets. The opening is reinforced by mechanical energy generated from the faulty current, compressed air or springs. The opening process is tripped by a solenoid [8]. Research shows that high heat energy is produced during the opening process (arching heat). Low voltage 400V ac circuit breakers are designed to conduct the load current with minimal production of heat energy. Also, they can withstand the arching heat. Such designs consist of contact sets that are made of highly conductive metals. These metals include copper, copper alloys and silver alloys. However, contacts are prone to subsequent erosion due to the arching effect. To overcome the erosion, low voltage 400V ac circuit breakers have disposable contact sets. Alternatively, in modern designs, the erosion is reduced by containing, cooling and extinguishing the arc. The reduction relies on the presence of insulating gas, vacuum, oil or air as arc extinguishers. Apart from the extinguishing mediums, technological advancements nowadays focus on lengthening the arc, partially dividing the arcs, jet-chambered intensive cooling, and zero point quenching [8]. The clearance of the faulty condition is followed by the restoration of the circuit. The restoration requires the closing of the contact sets. In modern low voltage 400V ac circuit breakers, the restoration process is reinforced by springs that are controlled with an electric motor. Solenoid valve and ball valve There are many types of valves operated electrically or mechanically. The electrical valves constitute of solenoid valves, while the mechanical valves constitute of ball valves. Regardless of the operation, many valves differ in terms of designs. Some designs constitute of valves with several fluid paths or ports. For instance, a two-way valve consists of two ports. In the context of operation, the opening of the valve signals the direct connection of the two ports. The connection allows the given fluid to flow through the ports [10]. The closing of the valve signifies the isolation of the two ports. Therefore, there is no fluid flow through the ports. Electrically, the opening of the valve results from the energization of the solenoid [9]. The valve in this state is known as Normally Open (NO). Contrary, the de-energization of the solenoid results in the closing of the valve. Such state is termed as Normally Close (NC). In other sophisticated designs such as the three-way valves, the valve contains three ports. Of the three ports, one port connects to either of the remaining two ports (supply and exhaust port). On the other hand, the ball valve contains a mechanically operated spherical closure component. The component controls the opening and closing of the valve. The control process depends on the port drilled through the centre of the sphere [10]. The parallel alignment of the port with the pipeline allows the fluid to flow through the valve. However, the 900C rotation of the sphere results in the perpendicular alignment of port with pipeline, thereby preventing fluid flow. Conclusion In conclusion, this paper presented a discussion that detailed the operating principle of several electric devices. These devices included 24V dc Relay, Submersible Pump, 230V ac Contactor, Rectifier (AC to DC), Circuit breaker (low voltage 400V ac), and Solenoid valve and ball valve. As such, it is notable that the operating principle of the discussed devices depends on the presence of electric current. The presence of electric current allows the devices to accomplish their designated functions. References [1] P. Pratumsuwan and P. Watcharin, “An embedded PLC development for teaching in mechatronics education,” In Industrial Electronics and Applications (ICIEA), 2011 6th IEEE Conference on, pp. 1477-1481, IEEE, 2011. [2] J. Z. Zhong, L. Y. Wen and Y. Yu, “Design of control system of annealing tin machine based on PLC,” Applied Mechanics and Materials, vol. 418, pp. 70-73, 2013. [3] V. Gurevich, Electric Relays: Principles and Applications, CRC Press, Boca Raton, FL, 2005. [4] G. Takács, Electrical submersible pumps manual: design, operations, and maintenance, Gulf professional publishing, Burlington, MA, 2009. [5] P. G. Slade, ed., Electrical contacts: principles and applications, CRC Press, Boca Raton, FL, 2013. [6] C. T. Chi, “A study of closing adaptive control in electronically controlled intelligent contactor,” In TENCON 2006. 2006 IEEE Region 10 Conference, pp. 1-4, IEEE, 2006. [7] C. Liu, W. Bin, Z. Navid and X. David, “A novel nine-switch PWM rectifier-inverter topology for three-phase UPS applications,” In Power Electronics and Applications, 2007 European Conference on, pp. 1-10, IEEE, 2007. [8] M. Steurer, F. Klaus, H. Walter and K. Kurt, “A novel hybrid current-limiting circuit breaker for medium voltage: principle and test results,” IEEE Transactions on Power Delivery, vol. 18, no. 2, pp. 460-467, 2003. [9] N. Ye, S. Scavarda, M. Betemps and A. Jutard, “Models of a pneumatic PWM solenoid valve for engineering applications,” Journal of dynamic systems, measurement, and control, vol. 114, no. 4, pp. 680-688, 1992. [10] K. W. Oh and A. H. Chong, “A review of microvalves,” Journal of micromechanics and microengineering, vol. 16, no. 5, pp. 13-20, 2006. Read More

Basing on the liquidated materials, submersible pumps are divided into corrosive water pumps, sewage pumps, sand slurry pumps and clear water pumps. The usability of all types of submersible pumps depends on their vertical operating mechanism. Whereby, regardless of the evolutionary changes that have occurred over the past years, the operating principle of submersible pumps remains the same. As such, submersible pumps produce liquidated materials when the impeller is rotated [4]. The production speed depends on the intensity of the centrifugal force that is dictated by the rotational speed of the impeller.

It is important to note that, kinetic energy of submersible pumps is lost in the diffuser. The diffuser represents the part of the pump where kinetic energy is converted to pressure energy. This explanation details the simplest operating principle of all types of submersible pumps. Contextually, there are other parts that are imperative to the operation of a submersible pump. For instance, the pump’s shaft connects to the protector (gas separator) at the pumps’ bottom base via mechanical coupling.

The connection allows the intake of the liquidated materials by the pump using the ‘screen’ part [4]. The intake is followed by a series of lifting, whereby, materials are lifted in stages with the aid of bushings (radial bearings) distributed along the pump’s shaft. 230V ac Contactor Unlike relays that are used to handle low electrical voltage, contactors are used to handle high electrical voltage. Basing on Slade (2013), contactors’ operating principle is slightly sophisticated [5].

In the case of 230V ac contactor, the current’s passage in the solenoid (electromagnet) produces a magnetic field. The field induces the attraction of the contactor’s moving core. Initially, the solenoid draws a lot of current that increases its inductance and causes the core to interact with the solenoid. The core’s movement propels the flexibility of the movable contact sets. As a result, the solenoid’s electromagnetic force binds the movable and the fixed contact sets of the circuit [5], [6].

The de-energization of the solenoid induces the springs’ gravitational pull that retracts the core’s movement leading to the opening of the contacts. It is necessary to note that, this explanation represents the basic operating principle of many contactors. However, in 230V ac contactor, the solenoid is partly covered with a shading coil. The coil’s role is to delay the core-induced magnetic flux. The delay necessitates the ‘averaging-out’ of the magnetic field’s alternating pull, thereby preventing the double line frequency buzzing of the core.

Alternatively, research shows that damages such as arching always accompany the opening and closing of the contact sets. In this regard, 230V ac contactors’ design consists of a tipping point apparatus that induces the quick opening and closing of the contact sets [6]. Although the quick opening and closing of the contact sets induce contact bounces that result in rapid unwarranted open-close cycles, modern designs have bifurcated contacts. The bifurcated contacts reduce the ‘bouncing-off’ and prevent arching.

Rectifier (AC to DC) Rectifiers are electric devices that are used to convert alternating current (AC) to direct current (DC). They are variably constructed due to their differential usability. However, their construction relies on a singular principle of operation. Whereby, the current passes through the rectifier’s circuitry in one free direction. With respect to Liu, Bin, Navid and David (2007), this means that the flow of current in the opposite direction of the circuitry is nearly impossible [7] (see fig. 1). The rectifiers consist of diodes (semiconductors) that are important in dissolving the heat generated by the conduction of the electric current.

Since diodes are ineffective in large rectifiers, such rectifiers are constructed with in-built heat sinks or cooling fins.

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