NFB ( NO FUSE BREAKER )

NFB (no fuse breaker) is one component of the electrical safety overload and short circuit. then what's the difference with the MCB?
be patient, we will discuss shortly.
the  function can be seen from the above definition of the meaning of that is, as a means to disconnect ( break ) electrical current when the load handled by the these tools becomes overload or short circuit, or the current through it exceeds that limit has been set at the NFB.

difference between the NFB with MCB is the limit value of current that can be served by both ini.MCB tool used for smaller load is typically modest and still can not diubah.sedangkan NFB has a larger current limit and used to secure his load currents more large and in some types of NFB anyone can set its current limit, of course, the greater the value of the current limit higher price NFB

HOW NFB WORKS 

Under normal circumstances:

after the tool is set current limit permitted. pull the lever to the OFF position and Rev to the ON position, so that an electrical current can flow and supply expenses.

overcurrent / overload / shortcircuit conditions:

electric current that flows through the tool and exceed the specified limits, then the metal bimetallic temperature inside will rise and the curved or bent, so that the contacts will be disconnected and the lever will go to the center position or TRIP. to restore it to its original state should be scaled first lever to the OFF position and then raised to the ON position. of course after checking the load and circuit underneath

HOW TO INSTALL NFB

before we put the NFB we have to count the total electric current  flow on this tools. to calculate the amount of current we can look at the name plate of a load (motor pump) and summing the the amount. then we determine the diameter of the cable conductor cross-sectional area accordingly. then we select the amount of NFB that will be used,

installation of equipment is series assembled on the top of  circuit and before the motor (load).

MCB ( MINIATUR CIRCUIT BREAKER )

MCB ( MINIATUR CIRCUIT BREAKER)  is an electrical device that is designed in such a way as to secure an electricity network from harm overload and short circuit.
FUNCTION MCB:

MCB serves to cut off power automatically if the power is delivered exceeds the limit value. This MCB is on / off, and can also serve as the main switch in the house. If the MCB is in a state bargainser off, then all the power in the house was halted. The switch is normally turned off when the repairs will be carried out electrical installations in the home.

MCB is a safety net that works on the principle of Bimetal, with some elements of the operation are:
1. Terminal trip (Bimetal)
2. Electromagnetic trip (coil)
3. Arc extinguishing
4. mechanisms of termination
By construction, the MCB has two ways of termination, namely: termination by heat and by electromagnetic.
1. Termination by the heat carried by the bimetallic rods, which are: combination of two different metals expansion coefficient of metal. If there is more flow due to overload, the bimetal will bend due to the heat and will push the breaker lever to release the mechanical lock. This causes the MCB trip.
2. Termination by ektromagnetik performed by the coil, if a short circuit occurs then the coil will be induced and the surrounding area there is a magnetic field that will pull the lever shaft and operate the breaker. To avoid the effects of melting, the high heat sparks that can occur when the termination will be muted by extinguishing arc (arc-shute) and sparks that arise will go through the blades of the arc-shute.
An automatic safety advantage is that it can be used again immediately after the termination, the automatic safety clutch freeway because there is otomatic clutch can not be used again if problem not improved.
The nature of the MCB are:
a. Load current can be considered when the heat generated heat in excess of permitted
b. Short circuit current can be decided without any slowdown
c. After the repair, the MCB can be reused.

The workings of MCB
1. Based on the heat. At MCB are bimetal plate (mix two different metals heat expansion coefficient). Bimetal will fold if there is excessive heat through. Bimetallic plates are curved because the heat will move the lever and the breaker will disconnect electric current.
2. Based on electromagnetic. Termination of electric current carried by the coil method is contained in the MCB. In the event of excessive current (MCB limit) will be induced so that the coil generates a magnetic field that will pull the lever breaker, so contact the MCB will be disconnected.

The size of the ability to decide MCB electrical current depends on the specifics of each MCB. For example, for a capacity of 2A MCB MCB will then work cut electric current when an electric current through the MCB exceed 2A. Each installation must take full account of the power requirements of each installation is installed.
It should be noted also for use in power installations that use the 3 phase occurs when the MCB trip (interference), the third MCB connected to each phase (RST) to open / end together.

DIRECT CURRENT ELECTRICAL MOTOR

direct current electrical motor  DC motors / direct current, as the name implies, uses a direct current indirect / direct-unidirectional. DC motors are used in special applications where high torque ignition or acceleration over a broad speed range.this is another article about electric motor while we have discuss alternating current electrical motor.

Figure 3 shows a DC motor which has three main components:

• Pole field. Simply put, the interaction of the two magnetic poles will cause the rotation of a DC motor. DC motor has a stationary field poles and armature that moves in the space between the poles bearing field. A simple DC motor has two field poles: north and south poles. The magnetic lines of force extend across the opening between the poles from north to south. For motors larger or more complex consists of one or more electromagnets. Electromagnetic receive electricity from an outside power source as the field structure.

• Dinamo. If the current goes through the armature, it will become an electromagnet. Cylindrical dynamo, connected to the countershaft to drive the load. For the case of a small DC motor, the armature rotates in a magnetic field formed by the poles, to the north and south magnetic poles change locations. If this happens, the current is reversed to switch poles north and south dynamo.

• commutator. This component is mainly found in DC motors. Its purpose is to reverse the direction of the electric current in the armature. commutator also helps in the transmission of current between the armature and resources.

The main advantage is the speed of DC motor is easy to control and does not affect the quality of power supply. DC motors can be controlled by adjusting:

• armature voltage - increasing the armature voltage will increase the speed.

• Flow field - reducing the field current will increase the speed.

DC motors are available in many sizes, but their use is generally limited to a few low speed, low to moderate power usage, such as machine tools and rolling mills because of problems with mechanical commutation at a larger size. Also, they are restricted for use only in areas that are clean and not dangerous because the risk of sparking at the brushes. DC motors are also relatively expensive compared to AC motors.

The relationship between speed, field flux and armature voltage is shown in the following equation:

Electromagnetic force: E = KΦN

Torque: T = KΦIa

Where:

E = electromagnetic force developed in the armature terminals (volts)

Φ = flux field is directly proportional to the field current

N = speed in RPM (revolutions per minute)

T = torque electromagnetic

Ia = armature current

K = constant equation

DC Motor Types / Unidirectional Flow

a. Separate power DC motor / Separately Excited, If the field current is supplied from a separate source, it is called a separate power source DC motor / separately excited.

b. DC motors own resources / Self Excited: shunt motor. In a shunt motor, the field winding (shunt field) is connected in parallel with the armature winding (A). Therefore the total line current is the sum of the field current and armature current.

Here's about the speed of a shunt motor (ETE, 1997):

• Speed ​​is not constant in practice depends on the load (up to a certain torque as speed decreases, see Figure 4) and is therefore suitable for commercial use with a low initial load, such as machine tools.

• Speed ​​can be controlled by inserting resistance in series with the armature arrangement (reduced rate) or by inserting resistance in the field current (increasing speed).

c. Own power DC motors: motor series. In a series motor, the field winding (shunt field) connected in series with the armature winding (A). Therefore, the same field current to the armature current.

Here's about the speed of the motor series (Rodwell International Corporation, 1997; LM Photonics Ltd, 2002):

• Speed ​​is limited to 5000 RPM.

• It must be avoided running series motor with no load because the motor will accelerate.

Series motors are suitable for applications that require high starting torque, such as cranes and hoists.

d. Motor DC Compound / Combined.

DC compound motor is a combination of series and shunt motors. In this motor, the field winding (shunt field) connected in parallel and in series with the armature winding (A) as shown in Figure 6. Thus, the motor has a starting torque nice and steady pace. The higher the percentage of incorporation (ie, percentage of field windings are connected in series), the higher starting torque that can be handled by this motor. For example, the incorporation of 40-50% makes the motor suitable for hoists and cranes, motors standard compound (12%) do not match

fuft..thats LOL all article about electric is make me addict but its fun to share with all readers,thanks