Overview: As the there is development in technology, machines and other ancillary instruments automatically get better and attain a level of sophistication. All the modern machines include a variety of systems to make them a comprehensive package. Electrical machines, electrical systems installed in industries and our homes rely on many different aspects to function optimally. These systems and gadgets include a lot of circuits which prove to be an important part of the entire instrument. These circuits need protection from trouble causing agents as well as factors like a fault in current or abnormal currents. Electric circuits can get damaged due to faulty or abnormal current activity and hence clever contingencies need to be arranged in order to protect the circuits from damage. As electric power always flows through the circuits protection to the circuits is always required. Circuit breakers are those safety mechanisms provided to protect the circuit from damage and unwanted situations
A variety of circuit breakers are available in the market and can be chosen according to the application. Air circuit breakers, Oil circuit breakers and some others are some of the types of circuit breakers available in the market.
Electromechanical type circuit breakers like MCCB [Molded case circuit breaker] and MPCB [Motor protection circuit breaker] are also some of the other circuit breakers which have ability to contain the damage against current faults, thermal overloads as well as the main reason of concern, short circuits! MCCB’s and MPCB’s both types of circuit breakers are devices which are able to close and open a circuit manually as well as a trigger or interrupt the circuit if any fault occurs, automatically. Even though both MCCB and MPCB devices are used for circuit protection mainly against overload and short circuit they have very few similarities in them if directly compared with each other.
Moulded case circuit breakers [MCCB]: moulded case circuit breakers typically use a combined i.e electro mechanical tripping units. These tripping units may be of fixed type or interchangeable type. A device like MCCB is able to provide protection to the circuit with the help of temperature sensitive device and electromagnetic device in tandem. Either of the two has a mechanical action on the trip mechanism. MCCB’s make use of one or combination of elements [tripping elements] that offers protection in overloading condition due to temperature, short circuits or current faults.
Thermal overload is caused when there is a piling up of temperature in between the insulator and the main conductor. If this type of overload is overlooked and unattended it ultimately deteriorates the insulator and results in a short circuit. By application of formulas to calculate heat with the help of resistance, current flow and the time period it flows through, overload condition can be easily predicted. If a clear indication between normal current and over current is predicted the circuit can be protected against it, with ease. At the given instance the thermal sensing element in the MCCB will trip in a matter of seconds and break the circuit.
Another fault that can occur in a circuit is due to ground fault, which happens to be a type of short circuit but more connected to the ground connection. Such faults occur commonly in LV systems. Arcing faults have a small value current hence are non detectable by the MCCB but if left attended can turn into a serious damage. Current electronic circuit breakers have the ground fault detection and protection inbuilt into the unit.
If high current flows through a circuit over and above the circuit’s permissible limits, that too because of the failure of insulating material, a short circuit occurs at such events. MCCB can instantaneously prevent the damage occurring in the circuit due to this high current.
Advantage of MCCB: MCCB units have a compact form factor, hence do not occupy large space in electrical installations. Due to the design of these MCCB units, they have very little or no down time as compared to other devices as if the unit is tripped it can be very well reset and can be functional within no time. MCCB units do not require special maintenance and up-keeping hence unwanted cost is reduced. MCCB units can be very well used in combination with other accessories and can be suitable for multi-purpose usage. If MCCB units are directly compared to the fuse unit, MCCB units cannot be classified as consumable part as the fuse hence one does not need to maintain inventory of the parts. Several faults can get cleared before changing the MCCB unit.
Application of MCCB: MCCB units can be used across a variety of applications including DC load feeders, UPS, Battery feeders, Furnace, Transformers and distribution feeders. Some welding applications can draw large amounts of currents hence require MCCB for protections. Electric motors can be protected by MCCB units. Shop for MCCB online at reasonable price.
Overview: MPCB [Motor protection circuit breakers] Some gadgets and equipment require specific attachment or a particular type of accessory for them to perform efficiently and at their peak efficiency. Circuit breaker as we know and is mentioned earlier, protect the crucial part of the equipment, the circuit, against a lot of different faults. Even though MCCB’s are used and can be used for a variety of applications including protection for electric motors, MPCB’s are made for specialty application. MPCB’s are the special kind of circuit breakers manufactured and designed specifically for protection of electrical motors. Electric motors are used almost everywhere, right from small applications to heavy duty applications and hence in order to avoid breakdowns these motors need enough protection from electric faults. All electric motors that are used in commercial or industrial applications can use MPCB’s effectively.
MPCB’s can very well be considered to be an application specific moulded case circuit breaker which essentially is a combination of short circuit and isolating gadgets which provide over current protection.
All the components of this circuit breaker are assembled and arranged in such a way that disconnection at the time of short circuit and overload detection can be possible immediately without delay. MPCB is a type of electro-mechanical device which can operate with circuits with 50 and 60 Hz frequency.
Functions of Motor protection circuit breakers: MPCB is capable of interrupting faults which lay apart from permissible limits, faults like short circuits, line faults with respect to ground and the line itself. If the motor draws current up and above its rated value, then there can be instances of overload. Hence MPCB’s protect the motor against overload conditions in which these breakers are adjustable. Generally three phase motor can face a lot of damage due to phase losses and imbalance. Motor protection circuit breakers can easily detect such faults and isolate the motor right away in turn protecting it from damage. If the motor is stopped due to overload it is dangerous to restart the operation immediately as it can cause serious and permanent damage to the motor itself, hence MPCB thermal delay does not allow the motor to be started immediately.
Modern MPCB units have the facility of fault signaling which means the circuit breaker will indicate the reader about the tripping of the breaker. Due to this the incharge personnel can be well aware of the tripping of the breaker and can effectively reset the breaker for connecting the electric motor again.
Working of MPCB: Basic working principle of MPCB is similar to that of other circuit breakers. MPCB’s are a type of thermal magnetic breakers having certain functions specific to only one application i.e. protection of electric motors. Motor starts with a high inrush current. Circuit breaker permits this starting current. Thermal protection is provided to the electric motor for tackling the overload condition. A motor which is unable to start after the inrush current flows through the circuit the circuit is broken to avoid damage due to the prolong stay of inrush current. As the breaker allows the initial inrush current it can only trip after a brief time interval, hence causing the action to be slightly slow and delayed. In case of line faults, short circuits or current faults magnetic protection is preferred. As compared to thermal action magnetic action is faster and immediate. As mentioned earlier motors operating on a three phase current require a voltage balance across the conductor. Imbalance of voltage more than 2% means increased damage to the motor and reduction in motor’s overall working life. Similar to imbalance, the motor can be damaged due to an abrupt phase voltage loss which will mean the motor has to run on only 2 phases. If the circuit breaker senses any difference in voltage in the phases it immediately trips and avoids any damage to the electric motor. Even though the imbalance in three phases is commonly observed in lines which cater to other loads which have single phase, but such condition is not acceptable in the case of electric motors.
Similar to MCCB’s, MPCB can be tripped manually for maintenance and replacement actions. Advantage of MPCB’s is that they can be configured according to the electric motor which means these MPCBS can be used to protect electric motors with a wide range of capacities.
Circuit breaker should always be chosen according to the application and rating. MPCB can be used in a large range of voltage setups right from 230V, 380V and so on right up till 660V AC. If the voltage is known the motor rating can be found out and a suitable circuit breaker can be chosen for effective protection. As mentioned earlier that MPCB’s can be configured according to the motor, it’s necessary to calibrate the circuit breaker according to the electric motor.
Applications of motor protection circuit breakers: MPCB’s can be used for protection of electric motors used in a variety of different applications and locations. For e.g. air conditioners installed on roofs, chillers and compressors as well as cooling towers. Electric motors can be found at places where water pumping is done, hence MPCB’s can be used in such scenarios. Elevators, conveyors and some other industrial machines which use motors can very well make use of MPCB’s for protection.
As MPCB’s are specially made for motor protections these devices help in increasing the working life of the electric motors and reduce cost of repairs if the electric motor is damaged due to faults. These circuit breakers have a special capability due which they can cater to some type of motors like asynchronous motors which are mostly used in industrial setups. MPCB’s work with other devices used for protection, for example, various timers, motor starters with reduced voltages or under voltage protectors. For effective protection action the circuit breaker needs to be chosen according to the rating and with comprehensive knowledge of the voltage conditions.
Summarizing the entire topic circuit breakers are designed to protect the circuit and in short the entire device from damage. Short circuits, line faults can cause damage and using traditional fuses is not advisable in special applications like electric motors. Circuit breakers offer various advantages and hence are effective for use in commercial and industrial applications. So some of the major differences that can be derived from the available information regarding MCCB and MPCB can be easily understood. MPCB’s are specially used for protection of electric motors where are MCCB’s are used in a variety of applications like transformers, distribution feeders, etc. MPCB has a certain delay in action in case of thermal protection which is required by some motor applications where as MCCB’s do not have such delayed actions.
A variety of MCCB’s and MPCB’s are available in the market and one can easily choose, buy these MCCB online at reasonable price. MPCB’s are also available from manufacturers like Schneider, who offers a variety of MPCB’s to choose from. Now browse through various models and know MPCB price online at just a click of the button.