Types of Distribution feeder system

Title: Main types of Distribution feeder system for beginners of electrical engineering.

Theory :

1)Radial:

In India most of the feeder system is radial feeder system its simple and least expensive, now a days big city's start using ring main system.

If fault occur in redial system would result in breakdown of supply of number of costumers until the fault is clear or extinguish.

           From single dig. you can understand there is only one supply to which all costumers are connected no backup supply is available,if fault occur on this feeder system result in whole area will black out. 

2) Parallel Feeder system.

This system is more reliable than radial feeder system but we are using two parallel line so cost is also double.

From above single line dig. you can understand the how we can transfer load from one line to other parallel line in case of fault.

          parallel system is also use full in case of load shedding of certain area,if we have short of Power not and not achieving demand then we can also shut some costumers while keep running others. 

         this scheme mostly use in URBAN areas now a days.

3) Ring main feeder 

        In ring main feeder sysem all substation are connected in ring such that the Start and finish end of the ring are meet at the same location, power is delivered by both pathways of the ring into substations located around the ring.

If any fault occurs on any point which is the around the ring then Faulty section is isolated by protective circuit breakers and the maintains supply continuity to other substation of ring feeder as per shown in above single line diagram.

       The advantage of Ring system is that if primary supply is break secondary supply keep running substations.

4) Mesh system.

This type of system use in Transmission and sub-transmission system This ensures that alternative supply can be available to customers in the event of failure of a transmission line or element.

        This is simmiler to parallel system only difference is that back up supply is available in mesh system.

Mesh system of transmission is use in outer rural area where difficult to reach in the event of fault.

Thanks

Kiran Patil

REX series temperature controller

Title: How to control temperature using REX series temperature controller.

Why: In industries, commercial sector some times temperature control of heater or the heater use in machine is necessary that time time we have to simultaneously ON-OFF the heater to avoid unwanted heating of coil.
      But using REX series temperature controller you can easily controller the temperature within SET limit.means once you SET the temperature on controller,yore heater coil take cut automatically at you're set temperature.
       To achieve temperature as per requirement we can get using REX series controller.

Procedure:

REX Series Temperaure controller

1) As per shown in fig connect the single phase AC supply to point 1 and point 2, Phase & Neutral                Respectively.

2) Now take loop from point 1 to point 3 which is phase wire as per fig.

3) As per above fig of temperature sensor 

where,

 Green Terminal = Is the Positive terminal (+) of sensor.

Remaining white terminal= you can consider any one as a negative(-) or common and connect them as per main circuit diagram,at point 8, 9  and 10.

4) Now connect the heater coil between point 4 and point 2, where point is work as neutral and point 4 is the out put of relay.

where at point 4 cut in and cut off of relay occurs means through point no 4 as per SET temperature supply is cut-in and cut-off to the heater coil.

                                                                                                                                                                  

     

      REX series controller view 

From above both fig. you can understand the circuit as per we draw and circuit dig indication by manufacture.  

Theory:                                                                                                                                                        1) The connection given by us is different from manufacture( He also right)  but our coonection are easy and simple so any one can understand REX series controller.for temperature control within SET limit. 

                                                            

                                                              REX controller front view  

2) As per in pic " PV " is you're temperature which is sense by temperature sensor and " SV " Is the temperature SET by you for limit.

3) Once you Reach temperature as per SET point your heater will take CUT-OFF as per shown in main Circuit dig.through point 4 which is relay OUTPUT.     

HOW TO SET TEM.

1) Press the SET button on controller which is shown in above pic.then you will see yore "SV" indicator start blanking then you can SET you're temperature as using UP DOWN keys also shown in pic.once done. press again SET.

Example 

If we SET "SV" 48 degree then you're heater take automatic CT-OFF once it reach at 48 degree.

2) This setting is sufficient for us for extra settings you can prefer manual which is provided by manufacture.

Conclusion: Using Above circuit dig. and steps you can easily control the temperature of any heater within 

limit.

Thanks

Kiran Patil

                             

Different types of temperature sensors.

Title:different types of temperature sensors
Why: Temperature sensor is the device which collect data from surrounding condition and give required out put in terms of temperature.

1) Thermocouples.

Thermocouple sensor is the most commonly used temprature sensor and it is abbreviated as TC. This sensor is extremely rugged, low-cost, self-powered and can be used for long distance. There are many types of temperature sensors that have a wide range of applications.

You can seen in fig.two different metals cromel and alumel connect to each other and out put gives us some Potential once input terminal is scene the heat.

A thermocouple is a voltage device that indicates temperature by measuring a change in the voltage. It consists of two different metals: opened and closed. These metals work on the principle of thermo-electric effect. When two dissimilar metals produce a voltage, then a thermal difference exists between the two metals. When the temperature goes up, the output voltage of the thermocouple also increases.

This thermocouple sensor is usually sealed inside a ceramic shield or a metal that protects it from different environments. Some common types of thermocouples include K, J, T, R, E, S, N, and B. The most common type of thermocouples is J, T and K type thermocouples, which are available in pre-made forms.

The most important property of the thermocouple is non-linearity – the output voltage of the thermocouple is not linear with respect to temperature. Thus, to convert an output voltage to a temperature, it requires mathematical linearization.

2) RTD (Resistance temperature detector)

RTD sensor give more accurate reading than other sensors, In this sensor the resistance is proportional to the temperature. This sensor is made from copper,nickel and platinum metals. It has a wide range of temperature measurement capabilities as it can be used to measure temperature in the range between -270oC to +850oC. RTD requires an external current source. However, the current produces heat in a resistive element causing an error in the temperature measurements. The error is calculated by this formula:

Formula = delta T=P*S

where, P=power produce                                                                                                                                   S=degree C/mill watt                                                                                                                               T= Temperature                                                                                    

There are different methods to measure temperature by using this RTD. They are two wired, three-wired and four-wired method. In a two-wired method, the current is forced through the RTD to measure the resulting voltage. but the main drawback is – the lead resistance is the part of the measurement which leads to erroneous measurement.

Three-wired method is similar to the two-wired method, but the third wire compensates for the lead resistance. In a four-wired method, the current is forced on one set of the wires and the voltage is sensed on the other set of wires. This four-wired method completely compensates for the lead resistance.

3)Semiconductor sensor

Semiconductor sensors are the devices that come in the form of ICs.or diode Popularly, these sensors are known as an IC( integrated controller ) temperature sensor. They are classified into different types: Current output temperature sensor, Voltage output temperature sensor, Resistance output silicon temperature sensor, Diode temperature sensors and Digital output temperature sensor. Present semiconductor temperature sensors offer high linearity and high accuracy over an operating range of about 55°C to +150°C. However, AD590 and LM35 temperature sensors are the most popular temperature sensors.

4) IR Sensors

Fig: IR sensor and IR sensor base temperature gun

IR (infra red) sensor is electronic instrument which is used to sense certain characteristics of its surroundings by either emitting or detecting IR radiation. These sensors are non-contacting sensors. For example, if you hold an IR sensor in front of your desk without establishing any contact, the sensor detects the temperature of the desk based on the merit of its radiation. These sensors are classified into two types such as thermal infrared sensors and quantum infrared sensors.

Thanks
Kiran Patil

DOL starter for single phase Motor

Title:- How to Provide overload protection to single phase motor using overload relay.
Why:- We have to provide over load protection to motor reason is that if our motor is over loaded it take more current than its rated capacity because of this winding start heating and may this burn the motor winding.
           if there is overload relay protection ( DOL starter) contactor un hold the supply and breack the circuit so motor will be safe ( different range of current setting available on relay as per motor capacity)

                                                                 Circuit Diagram..
Apparatus:
1)Three phase contactor
2) Thermal overload relay(As per motor capacity)
3) wire Sqmm as pwer

Procedure:
1) Firstly take 220V 50 Hz. supply and connect to point no 1 & 2,Phase & Neutral respectively as per shown in figer.
2) connect wire loop between point 3 & point A2.
3) Take wire from point 1 to any one of the terminal of START (means N/O terminal ) button.
4)then take wire from point A1 to point 95 as per fig. and also take wire from point 5 to middle terminal of overload relay as per fig.
5) Connect all three terminal of contactor to over load relay( means insert contactor terminals in realy ) as per fig.
6) take wire from point 96 and connect to remening terminal of of START button (means N/O ) as per fig.
7) finally take Phase and Neutral and connect to motor terminal.
8) after all connections as per fig. you're motor ready to run with overload protection .

Conclustion: using these you can easily provide overload protection to motor to avoid inrush of current.

Thanks
Kiran Patil