Thermistor rtd

Thermistor is a tool or component or electronic sensors used to measure temperature. The basic principle is the change of thermistor resistance value (or barriers or werstan or resistance) if the temperature or the temperature of the thermistor is changed. The thermistor is a combination of the thermo (temperature) and a resistor (resistance gauges). Thermistors are made of semiconductor materials and work in the opposite way with RTDs.

While RTDs (resistance temperature detectors) increased with increasing temperature resistance, thermistor tend to show lower resistance with higher temperatures. This is because the semiconductor material tends to deliver more electrons as the temperature increases. Thermistor was discovered by Samuel Ruben in 1930, and received a patent in the United States. There are generally two types of thermistors: Posistor or PTC (Positive Temperature Coefficient) and NTC (Negative Temperature Coefficien). PTC resistance value will rise if the temperature is rising, while the NTC just the opposite.

Thermistor or thermal resistance is a semiconductor device that behaves as a prisoner with a high temperature coefficient of resistance, which is usually negative. Generally the thermistor resistance at room temperature can be reduced by 6% for each 1oC rise in temperature. High sensitivity to changes in temperature makes the thermistor is very suitable for measuring, controlling and temperature compensated precision. Thermistor is made of a mixture of metal oxides deposited such as manganese (Mn), nickel (Ni), cobalt (Co), copper (Cu), iron (Fe) and uranium (U). Summary of prisoners is of 0.5 ohm to 75 ohm and are available in various shapes and sizes. Smallest size mani-shaped beads (beads) with diameter of 0.15 mm to 1.25 mm, shape disc (disk) or ring (washer) with a size of 2.5 mm to 25 mm. The rings can be pinned and placed in series or parallel to increase power dissipation.

Although many types of thermistors are available, two-wire thermistors are the most common for temperature measurement. Thermistor should check the measuring resistance (ohms). Using the digital and analog multimeters, You should be able to see the value of transducer ohm stable at room temperature and decreases as the tip of the transducer when heated. thermistor generally have a large change in resistance per degree temperature.

The best way to test when the thermistor thermistor is connected to the controller. you need to check with a multi meter in VDC mode, then plug the cable in connection thermistor probe. At room temperature (25 degrees) you will receive 2.5VDC, 5VDC if you accept this means that there is no connection or resistance (ohms) on the thermistor. If you receive a 0 VDC means that there is a short in the thermistor. There is a controller that works at 3.3V, the controller decides when thermistor current is 3.3 VDC. at room temperature (25derajat) we get 1.7 VDC, of ​​course, the results vary depending on the room temperature. PTC thermistor has a resistance (ohms) which increases with increasing temperature. NTC thermistor has a resistance (ohms) which decreases with increasing temperature. Another way is to check the thermistor, measuring with a multimeter on a scale themistor kilo ohms. If the change in resistance (ohms) is infinite or no resistance at all, means the thermistor in a state of disrepair.

Thermistor or thermal resistance is a semiconductor device that behaves as a prisoner with a high temperature coefficient of resistance, which is usually negative. Generally the thermistor resistance at room temperature can be reduced by 6% for each 1oC rise in temperature. High sensitivity to changes in temperature makes the thermistor is very suitable for measuring, controlling and temperature compensated precision. Thermistor is made of a mixture of metal oxides deposited such as manganese (Mn), nickel (Ni), cobalt (Co), copper (Cu), iron (Fe) and uranium (U). Summary of prisoners is of 0.5 ohm to 75 ohm and are available in various shapes and sizes. Smallest size mani-shaped beads (beads) with diameter of 0.15 mm to 1.25 mm, shape disc (disk) or ring (washer) with a size of 2.5 mm to 25 mm. The rings can be pinned and placed in series or parallel to increase power dissipation.

In operation utilizing thermistor resistivity changes with temperature, and the prisoner fell generally values ​​exponentially with temperature for the type of NTC (Negative Thermal Coeffisien)

RTD (Resistance Temperature Detector)

RTD is a resistance temperature detector, this sensor will produce a change in resistance with changes temperature.Nilai huge detainees would be proportional to the measured temperature. Increasingly high temperature, its resistance will increase. Formula is used:

R = apha * (T - To) + Ro

Description : alpha coefficient of metal (temperature resistance) [/ * C]

Most RTD is made of Platium with baseline resistance 100 Ohm at 0 º C. In this setting, change the RTD has a resistance of 0.3729 Ω / º C.

Resistance Temperature Detector (RTD) or known to the detector Temperature resistance is a tool used to determine the value or scale a temperature / temperature sensitive elements of using wires platinum, copper, or pure nickel, which provides limited resistance value for each temperature in the range of temperature. Getting hot objects is, the greater the resistance value or the higher power, as well as otherwise. RTD PT 100 is the most popular type used in industries. Resistance Temperature Detector is a passive sensor, because the sensor require energy from outside. Elements commonly used on prisoners wire resistance is nickel, copper, and pure platinum mounted in a tube in order to protect against mechanical damage. resistance Temperature Detector (PT 100) is used in the temperature range -200 ° C up to 650 ° C.

Thermistor rtd Difference :
Thermistors
- Material used in a thermistor is generally a ceramic or polymer
- Responses temperature thermistors typically achieve a deeper level of precision within a limited temperature range.

RTD
- Materials used were pure metals
- RTD temperature ranges greater response

Temperature measurement

MEASUREMENT OF TEMPERATURE

Definition temperature is a as degrees heat or cold an object, based on scale which derived from symptoms physics which can be observed. For the purposes of engineering, temperature is a measure termopotensial compared with pressure head or electrical voltage. In temperature measurement is needed its benchmark as the price basic, reference point this is needed in general for detect temperature utilized the thermal properties another of a workpiece, eg expansion properties & thermic. Because price of coefficient of expansion an ingredient are not always constant for the entire regions temperature, then the sensitivity a tool need for the calibrated for the entire range measurement.

Temperature scale that is often used is deg Celsius (0C) and deg Fahrenheid (0 F). Celsius temperature scale using the reference, and the freezing point of water vapor price of 00 and 100 0C, respectively, were Fahrenheid scale using the same reference to the price of 320 and 212 0F. Because it uses the same reference, then Darajat Fahrenheig degrees Celsius and can be converted to each other:

0F = (9/5) X (+ 320 0C) or C = (5/9) X (0F-32)

In the development it was found that all the molecular vibrations will stop at a certain price. In this case the price observed at -273 0C is the lowest temperature attained from practice. -273 0C temperature is used as a reference by kalvin, called the -273 0K (Calvin). Kalvin temperature called the absolute temperature, and 0K often called absolute zero temperature. Conversion between the Celsius temperature is 0K kalvin = 0C + 273.150

 While the absolute temperature scale based Fahrenhet is Rankine :

459.690 + 0R = 0F

Temperature Gauge Principle
Temperature scale is not measured directly, the temperature measurement is always based on the physical properties of a particular object change due to the influence of temperature change. Change various objects that are used as the basic principle of a thermometer, In general there are two methods for measuring the temperature of mechanically and electronically.

Mechanical methods using sensors that respond to temperature changes with changes in the mechanical properties such as deformation of the bellows, diaphragm or Bourdon element. Method of electronically using sensors that respond to temperature changes by producing changes in electrical resistance or voltage.

Temperature Gauge
Temperature scale is not measured directly, temperature measure is always based on the physical properties of a particular object changes due to temperature change, as changes in objects that are used as the basic principle of a thermometer, among :
1.Change object dimensions, for example:
- Thermometer in buld liquid (mercury thermometer), which is based on the principle of volume measurements in buld (expand and shrink the volume of mercury in the buld) if associated with a particular medium they want to know.
- Bimetal thermometer, based on differences in the coefficient of expansion of two different metal plates.
2. Voltage changes, based on the different nature of the two types of materials thermoelekrik (thermocouple).
3. Changes in the electrical resistance of an object, thermo resistance (PT-100).
4. Fluid pressure changes in the buld (pressure thermometer).
5. Resonasi on crystal frequency changes.

Fluid in the thermometer bulb
Fluid in the buld thermometer works by:
Volume changes caused by changes tempertur, liquids contained in this buld is used to measure temperature. Where in general the volume changes that occur is small enough, then the system used in the capillary reservoir
Fluid pressure change, in which the fluid pressure detected by the pressure gauge, such as bellows and tubes Bordon.
a. Buld a fluid-filled
b. Filled System Thermometers

Limit of the measurement range is used, the point of evaporation, boiling point and freezing point fluid. But the coefficient of expansion of a fluid is not always constant between the reference point, the temperature measurement range is limited to a constant expansion properties.

Temperature measurement is strongly influenced by the "Rise time" and "settle time". Rise time and settling time is the time required to measure according to the actual temperature. One example, the mercury thermometer takes time (settling time) 3 minutes for measurement in accordance with the actual conditions.
This is caused by the transfer coefficient drawstring contact between the glass buld Dangan measured media. So that the measurement results can be observed with the fast temperature sensor required small dimensions.

Buld which contains the fluid

Sensitivity of the fluids can be derived as follows buld.
 fluid volume change = V
  V = volume of liquid in the buld
    = Coefficient of expansion of fluid volume
  = Change in temperature of the medium, if the change in temperatures ranging from 0, then it can be declared as a medium temperature (Ti).
Volume changes will be accommodated by the pipe capiller and observed as an increase in fluid in the pipe kapiller (x).
 
SAMA (Scientific Apparatur Manufactures Association) filled system thermometers split into four classes, namely:
1. Class I system, the liquid working fluid (not including mercury). Used for the measurement of temperature - 125 oF to 600 oF. Minimal span 25 oF and 450 oF maximum, as well as the order of the speed of response 5-10 seconds. Scale is uniform except at low temperatures.

2. Class II system, the working fluid in the form of steam. Used to measure the temperature of - 430 oF to 600 oF, with a minimum span of 40 oF and 300 oF maximum. scale is not uniform and the response speed of the order of 5-10 seconds.

3. Class III system, the working fluid gas. Used for temperatures from -400 oF to 1500 oF, with a minimum span of 180 oF and a maximum of 1000 oF. Uniform scale and order response time is 1-5 seconds.

4. Class IV system, the working fluid mercury. Used for temperature measurement from -40 oF to 1000 oF. Uniform scale and order response time of 4-5 seconds.

Pressure Thermometer
This instrument is used to measure the temperature at which glass thermometer may not be used or are away from a power source, such as the fields of oil drilling.

Bimetallic Thermometers
Bimetal thermometer uses the principle that the metal will expand when the temperature changes. Two metal plates (bimetal) that have different expansion coefficients used in this type of thermometer, which is fitted into a single unit. A change in temperature will cause different expansion at the plate, causing the arch

To obtain greater sensitivity, the selected materials that have a high expansion, material B ekspanpansi lower. Metallic material that is often used is invar (a mixture of iron and nickel) as a metal with a lower coefficient of expansion and brass or nickel as a metal with a higher coefficient of expansion. Brass is used at low temperatures, while nickel is used at high temperatures. Bimetel than used as a measuring tool is also used as a control element in Temperature Control System (thermostat) on the type of on-off control. Kontruksinya among others, in the form of: Spiral, U shape, Waser, helical, double helical.

Thermocouple
The working principle of the thermocouple is based on pembngkitan voltage due to temperature differences between the joints of a pair of different metals, which can be expressed mathematically by the formula:

                      E = μАВ (Тs - Тr).
where:
                     μАВ = constant termoelectrik
                        Тs = temperature at the sensor connection
                        Тr = temperature at the connection references

Materials are often used for example: Copper-Constantan (for the range - 300 to 600 oF). Chromel - Alumel (For the range -300 to 2300 oF).
At this termocople system works three kinds of effects that are interrelated:
- Seeback effect, if the temperature in both junctions are different, then there will be an electric current whose magnitude depends on the temperature difference between the two Juntion.
- Paltier effect, termocople When the electric current flowing, the temperature at Juntion will change according to the direction of power flow. The temperature at first Juntion may be higher than the medium temperature and the temperature on the other lower Juntion.
- Tamson effect, if the electric current flowing in the second thermocouple wire has gredien temperature along the wire (no drawstring flow), then the heat will be generated at any point where the direction of the electric current equal to the flow direction drawstring, and drawstring will be absorbed in the reverse direction.

Law - legal termoelectrik, can be expressed as follows :
1. Thermocouple voltage at Juntion temperatures T1 and T2 are not affected by temperature in other parts of the circuit, if the metal wire used two homogeneous.
2. If the wire is homogeneous (C) in pairs in wire A or wire B, all new Juntion have the same temperature, the voltage generated in the circuit does not change.
3. If the wire is installed on C Juntion, along AC and AB same temperature, the voltage in the circuit is not changed, the same as if the wire is not attached drawing C-4c).
4. If the AC voltage on the thermocouple is EAC, teganagan in BC is EBC thermocouple, the voltage AB is EAB = EAC + EBC (image-7.4d).
5. If the thermocouple produces a voltage E1 at Juntion temperature T1, and T2, and E2 at Juntion temperatures T2 and T3, the voltage at temperature T1 and T3 Juntion is E = E1 + E2.

Temperature Measurement Using Electrical Resistance.
The working principle is based on price changes in electrical resistance wire sensor as a result of temperature changes. in general, as the temperature rises, the price of electricity goes up detainees anyway. In the form of a mathematical relationship between the price of resistance to temperature is expressed by the formula:
                    Rt = Ro (1 + dt)

Where: Rt = temperautr electrical resistance at t ° C (ohm)
                   Ro = temperautr electrical resistivity at 0 ° C (ohm)
                    ð = coefficient of resistance to changes in temperature (ohm / ohm °)

Custody of a particular substance will change its temperature to change, this is the basis of the temperature detection method. Conductor materials used are metal and semi-conductor materials. Conductor material first discovered this once called RTD (resistance temperature detector).
shows the temperature curve of the resistance price. From the curves it appears that platinum has the most linear curve A platinum resistance thermometer to determine the temperature of the international standards in the region from -270 ° C to +660 ° C  

  

Sensor element is made of a variety of forms for fluid temperature sensor, winding-resistance-wire, inserted in a stainless-steel buld to protect from liquid or ges karosif. Various plate-grid-winding terperatur used to measure the solid surface, the layer is also used to replace platinium wire windings (winding-wire).

 
Thermistor
First of all thermistors are made ​​from Manganese, and Cobalt-nickel oxides, mixed in appropriate proportions and processed in the form of a backfire, then in sentring. Compared with the type conductive sensor (which has a small and positive coefficient), termister nekatif have large temperature coefficient). Thermistor type conductors is very non-linear, see Figure-7. The relationship between resistance / terperatur in the form of: R = Ro e (1 / To + 1 / T)
where:
R = Resistant thermistor at temperature T.
Ro = Hold the thermistor at temperature To.
= Constant, the characteristics of the material, K
e = exponential
T & To = the absolute temperature, K  

When used to measure temperature, thermistor requires lenierisasi series, because the relationship between temperature and resistance is unbelievably not linear.

Pyrometer
Pyrometer is a temperature gauge price based radiation emitted from the heat source to be measured temperatures (such as ignition on boiler), nonkontak measuring system with a source temperature measured, where a hot objects emit heat and light kesekelilingnya, the higher terperatur objects, the more large
and the intensity of the emitted light. By measuring the amount of radiation emitted or heat or light, temperature objects can be known.

Pyrometer to determine the temperature of the object by measuring the total radiation or radiation wavelength one, on the basis of the known two kinds pyrometer, which :
- Heat radiation pyrometer Determination of temperature by measuring the total radiation emitted an object (see Figure-8). Radiation is measured with temperature sensors, such as thermocouples, thermistors.

Optical Pyrometer
Optical pyrometer using comparative methods as basic operations. In general, is taken as a reference lamp filament is electrically heated. and the temperature is obtained by comparing the size of the optical radiation from the filament and visual visual radiation from the source to be measured temperatures. There are two methods of temperature measurement of optical pyrometers premises, namely: Control the electrical current in the filament electrical resistivity rangkaian.Metode premises set this variable using the comparison lights. Optically regulator thermal radiation received by the pyrometer using several tools such as filters polarisator absorber. Optical wedge or slice daphragma. This method uses a constant intensity comparison.

Excess optical pyrometers are :
- Does not require contact with the target being measured
- Very useful for high temperature
- Accuracy is high enough

The disadvantage is :
- Relatively expensive
- In the manual type allows the emergence of operator error, nor can they be used for the measurement as a - Component of the control system.
- Measurement is affected by the material emissivity.

way of twisting and dismantle electric motors

Electric Motor

Coil wrapped around and unload the module is a module that has the scope to dismantle and re-roll the stator alternating current electric motor 1 phase and 3 phase induction motors. This module consists of 4 learning activities. 1 is a revision of Planning and Preparing for Employment, Learning Activity 2 contains about unpacking coils on electrical equipment, Learning Activity 3 contains about assembling the coils on electrical equipment, while the fourth contains learning activities on the check and report the completion of the work. By using this module in the training participants are expected to re-roll the stator of an induction motor 1 phase and 3 phase. To be able to do the learning module entitled "AND disassemble the coil wrapped around" should be training participants must have the ability to start, namely :

1. master the basic theories of alternating current electricity
2. master series / parallel load 3. control of magnetic circuit
4. master the principles of energy conversion
5. 3-phase power control circuit
6. skilled labor using hand tools on the work bench and montage work.

Plan and prepare for what type of motors that we will we dismantle or wrap. For this work we plan and prepare the type of induction motors single phase and three phase induction motors. We choose the type of motor is widely used type of industrial environment and usage in the community. Theoretically a single phase induction motor can be distinguished into: 

1. Split phase motors 

2. Motor capacitors 

3. Shade pole motor 

4. And others. 

While the three-phase induction motor (Three phase induction motor) is also called a poly-phase induction motor is an electric motor having a stator coil 3 pieces are mounted on the circumference of the stator is located shift 120o each electrical or mechanical. appropriate with his name, then this type of motor requires alternating voltage source three phase. Construction of single phase induction motors and three phase induction motor consists of two main parts :
1. Stator In principle, the induction motor stator is equal to the synchronous motor starter and generator. There is a wire in the stator arrangement is entered into a groove for receiving the stator windings of the motor will take turns according to the type of motor single phase motors for example, the stator windings will carry a single phase, where the voltage is fed from one phase while the provider for the type three-phase motors, the stator will bring a three-phase winding is fed by three-phase voltage provider. The number of poles of the motor will determine the speed slow rotation of a motor. Greater the number of poles are installed then the slower the revolution generated when the number of poles, while the less the resulting spin faster and faster. This sort of thing can be calculated from: 

Ns = synchronous round
F   = Frequency meshes
P   = Number of pole pairs

2. Rotor Rotor of an induction motor can be divided into two general categories :

a. Rotor Cage
In general, almost 90% of induction motor using a rotor with a lot of this kind. Because the rotor of this type, the induction motor is the simplest and most powerful type of rotor is made of silicon steel and consists of a cylindrical core that is parallelwith groove / slot and filled with copper or aluminum in the form of bars.
b. Rotor Winding
The rotor has a winding-wire entanglement is distributed so that the motor of this type also can be functioned as an alternator (generator) so this will have on the rotor poles in the stator winding of the internal rotor motor is connected in star (three phase) and terminal entanglement is removed and connected to three insulated slip ring that is placed on the motor shaft with a brush on it. The third brush is externally connected to a reostat to form stars. Reostat the motor serves to increase the torque of the motor asut during the investigation period. If the motor is working in normal conditions, the slip ring is automatically connected to short. So that the ring over the shaft connected together by a metal which further depressed the brush automatically lifted from the slip ring which serves to reduce friction losses. Besides these two main parts of induction motors also have additional konsturksi include home stator, stator cover, fan and terminal circuit.
Stator In principle, the stator is part of the electric motor is not rotating at the stator besides that there are grooves that contain coils of wire.
Rotor In principle, the rotor is part of a rotating electric motor. Rotors on electric motor can be divided int, rotor winding and cage rotor

• When the number of poles plus it happens the rotor rotation produced will be reduced. 
• When the number of poles on the motor is reduced so that rotation of the motor will occur increases.
• If the composition of silicon (carbon) plus, then what happens stator will be brittle and prone to rupture and the resulting value of the magnetic flux will increase.

 picture 1

how to remove pulley

remove the stator and rotor

 

remove the stator coil

The stator coils form Form of an induction motor stator coil 1 phase can be divided into three types, this kind of thing is depending on how wrapped into the stator grooves. Coils form are as follows :
a. Coil loop or coil overlap (lap winding can also be called a spiral coil
b. Central spindle (concentric winding) 
c. Spindle waves (wave winding

Function of the coil is as follows: 

a. Snare coil (spiral) benyak used for motor (generator) with a relatively large capacity. Generally for middle and upper classes, although typically there is an electric machine with a larger capacity, use the system kosentris stator coil. 

b. Center coils (concentric) in general the system is widely used for motor and generator with a small capacity. Although there are also special motors with small capacity using a coil with a special type. 

c. Spindle waves / wave winding for the motor winding systems with large capacitors are widely used. 

2. Ways to roll back the stator coil 1 phase induction motor Induction motors 1 phase is essentially the same as the 2-phase induction motors. This sort of thing we see, that in one phase induction motors, there are 2 types of coils, the primary coil (running winding = RW = RV) and the auxiliary coil (starting winding = SW = RB) has a second coil of wire cross section and the amount of twist that not the same. But there are times when it is made ​​almost the same. 

The main coil wire has a cross-sectional area larger and more winding number. As for the auxiliary coil has a small cross-sectional area and the number of windings a bit. If one phase induction motors supply us with a certain voltage, the magnitude of currents in both the coil and the Iu and Ip or can we write Ir and Is will have different values​​. Thus it will affect the current value Iu and Is having a 90 ° phase shift electrical (el 90o).

a. Step Coil Intended to measure ground coils is the angle formed between both sides of coil and rated with a letter Yg. To get the maximum spin coupling, the coil should be the same steps with a long pole. The pole distance is the angle between the north pole ground (N) and south poles (S) the nearest. While the distance poles are marked Tho and a distance of electric pole is 180o. When the number of pole pairs of a motor is p, then the total polar is 2p and comparison between the degrees of a circle (degrees of arc = OBS) and degrees of power (OEL) we associate with the pole, then we take the example =
To = P = 1, then 360obs = 1 x 360oel
P = 2, then the 360obs = 2 x 360oel
P = 3, then the 360obs = 3 x 360oel

Thus the comparison between OBS and OEL can write the formula: aobs = p.aoeL When the number of grooves in the induction motor stator is G 1 phase of the groove, the grind angle around the stator or a time slot is 360 º G bs. When a motor has a total G groove was = p.360oeL. a = 2p distance around the stator pole or beam G = 2p pole distance. So: a polar distance = 1E = 180o eL =, because the measure Yg = 1E coil, the coil measures to:

 

To obtain the maximum swivel coupling, then the required number of turns a lot, it may not be accommodated on a single stator grooves. For it must be divided into several grooves. This means that for a single coil flow will be divided into a number of windings (coils). For single-phase induction motor having a pair of poles with a single coil that consists of several coils consisting of several coil sections and each section requires two coils stator grooves thus, for single phase induction motors which have 1 pair of poles will have a coil sections. 

b. Amount of flow per pole per phase If the number of phases = m, then each phase will have as much G/2p.m coil section, so that on each pole for each phase will take as much G/2p.m groove groove. If the number of grooves on each pole for each phase is marked with the letter g, then the number of grooves per pole per phase to be g = G/2p.m groove. 

c. Placing coils (Shifting Place) To put the coils on each phase, then rub against each other should always be placed where. This sort of thing which aims to turn dihasilkanselaing coupling phase shift. For two-phase induction motor phase shift, for 2 swivel coupling (power play) is 90 ° eL. If shift points are provided with a letter YF, then D = 180 o eL so for motor 2 phase, the value of YF = ½ D. From the description above, it can be obtained several formulas that can be used to convolute induction motors as follows: 

The formula for AC motors wrapped around the stator :

&p      = Step plot of the coil 1 coil 2 kesisi
G       = Number of grooves
2p      = The number of poles
p        = Number of pole pairs
q        = Number of coils per group
m       = Number of phases
KAR = flow range is the degree of radical
KAL = flow range is in electrical degrees
Kp    = the phase range is
K      = Number of the coils in each pole

2-phase AC motor line number 24, 2 pole pairs of the double stage calculation :

 

2 phase motors can be used for motor 1 phase by making a larger coil wire and more number of email as the main poles (KU) and the opposite as the poles help (KB) It was meant to happen different phases, resulting in a moment turn. Because of this the single-phase motors can be wound concentrically with KU and KB are the snare (to mix). 

Stretch of Mixed Picture 

 

Been tried with entanglement meshes KU = 50 convolution, and KB: 40 convolution,  = 4 mm, working at a voltage of 50 watts 

3. Motor 3-phase Induction Motor with a road system (single layer) For three phase motors, the entire stator grooves are divided into three equal lots so that each phase has a coil of as much as G / 2.P.3 coil. If the phase phase = m, then each phase will have a coil as much as G / 2.Pm How to install the coil that is when one is in front of the poles of U, then the other side of the pole must be located in front of S. That is because each phase has a coil of as much as G / 2.Pm, then at each pole of each phase will occupy a plot as much as G / 2.Pm groove. If the number of grooves on each pole for each phase diberikan g mark, then the number of grooves perkutub perfasa namely: g G / 2.Pm groove. As for how to roll the motor 3-phase stator coils in principle the same as the motor 1 phase, two phase, the difference is in the coil (the coil). For 3-phase motors of each winding is placed as far away as rub against each other so 120oel 2/3 the distance pole or = 2/3 winding steps (D) For motors with a size of 500 watts or more would be more economical when done (made​​) 3 phase. Because when executed by 2 or 1 phase, then the motor would have to use a condenser (capacitor) with a relatively large capacity. So it would be very detrimental, due to the properties of the condenser. To clarify the above description, the following are some examples of 3-phase motors to be done rolling back. 

The formula for AC motors wrapped around the stator :

To doubel layer :
&p     = Step 1 plot from side to side coil of the coil 2
G       = Number of grooves
2p      = The number of poles
p        = pairs of poles
q        = A lot of the coils of each group
m       = Number of phases
KAR = range is in the degree of radial grooves
KAL = flow range is in electrical degrees
Kp    = the phase range is
K      = number of coil sides per pole

instrumentcontrolling

Why proximitor need -ve voltage input

When Don Bently worked on making solid-state versions of the eddy-current measurement system (it was actually originally designed in the 1930s by GE engineers using vacuum tubes), he had a choice between using N-P-N transistors or P-N-P transistors. At the time, transistors were quite expensive, so he chose the least expensive of the two: P-N-P (apparently, PNP transistors they were less expensive to manufacture 50 years ago than their NPN counterparts).

Because the circuits used PNP transistors, a negative bias voltage was required rather than a positive bias voltage. Don chose -18V. This was later changed to -24V to allow more linear range from the transducer.

At that time, the industrial instrumentation community had not yet standardized on +24 vdc, and by the time they did, there were so many Bently Nevada eddy current vibration sensors installed that changing to +24V rather than -24V was not greeting with enthusiasm by users. Hence, it has remained -24V to this day.

axial vibration

THRUST POSITION MONITOR SYSTEM (AXIAL) 7200

Displacement axial measurements

The working principle, the rotation of the rotor shaft, will cause movement of the shaft either positive or negative direction from the neutral / middle. The motion was detected by probe type and eddy currenr proximitor generating output electrical signal which is proportional to the distance between the probe shaft. Or observe the surface of the rotor.

Monitor changer proximitor to generate any output readings recorder position thrus and dc output signal proportional to the position of thrust. With the movement towards positive or negative shaft Which one will mengobah Thrus to individual dc signal level. DC level is then received by Indicator (Front panel meters), Recorder Driver Circuit. Alarm circuit can be adjusted by adjusting the set point, alarm indicator lights and signal relay alerts to be received. To keep from happening malfuntion or malfunctions then to make sure whether there is danger or not before the shutdown, then used AND logic, where if there is danger of a second transducer signal there will be a shutdown, if it happens one channel failure will not hear the alarm false.

12:17 captions, Proximitor merobah -24 Volt -18 Volt DC or DC to RF signal that is sent to the probe through a 95 ohm extension cable that causes alternating magnetic field. If there is no conductive material is cut, the magnetic field, there is no loss of power in the RF signal. With no power is lost in the RF signal, the output signal will approach proximitor -22 Volt DC (-24 Volt DC power supply).

Figure 12:17 Wiring diagram Dual Thrust Monitor

As the picture below is the theory of the Axial displacement measurement.

12:18 Picture Diagram Probe Thrust with Proximitor

Caption 12:18, When a conductive material (rotor shaft) approaching probe, eddy currents will be generated as the magnetic field is intersected by a conductive material (rotor shaft), which will result in loss of RF signal power or voltage will be reduced as well (directly proportional). When the surface of conductive material (rotor shaft) perilously close to the probe, the more power is absorbed through the eddy currents on the surface of the conductor material. When the probe is very close to the surface of conductive material (rotor shaft), then the maximum power is lost from the RF signal will be shown as the minimum output signal of proximitor. Proximitor will measure the amount of RF signal and is shown as a negative DC output signal, selanjudnya through an amplifier circuit. The monitor will show the amount of Axial Displacement happens as read on the meter.

12.3.2 Procedure setting of Axial Displacement and Radial Vibration.

12:18 Picture Position Probe against Thrust coller

Before we do the settings for the Axial Displacement, it first has to consider the following steps:
1. Determine the gap / clearance between the thrust collar and thrust bearing. for example: 0.32 mm.
2. Scale factor of proximitor must be known.
For example: have a scale factor proximitor 200mv/mils.

If the requirements are met prior to setting, then:
a. Move the rotor shaft to travel the maximum position on the dial reads micro meter by 0.32 mm, according to the calculations for the 0.32 mm gap = volts DC.
Given: proximitor scale factor 200 mV / mils.
1 = 25.4 mils (microns)
1 = 0.001 mm
1 mils = 25.4 x = 25.4 mm
1 mils = 200 mv


X 25.4 mm = 200 mV.

 = 7.87 volts DC.
So: 0.32 mm = 0.32 x 7.87 Vdc = 2.5 Volts DC.

b. It is known from the calibration curve and proximitor probe.

eg: Voltage gap setting = 10 volts DC.

So the position of the shaft can be pushed to the maximum positive or negative travel, or when the voltage = 10 V

c. next when the rotor shaft is driven in the direction of travel set maximum positive Axial probe in such a way that a digital volt meter attached to the output terminals and the common proximitor reads 12.5 volts DC.

d. When the rotor shaft is driven in the direction of maximum negative trevel Axial probe set such that the digital volt meter attached to the output terminals and the common proximitor read 7.5 volts DC.

e. Selanjudnya observe on the monitor when the rotor shaft is driven trevel maximum positive or negative, the reading will symetris +0.16 mm and -0.16 mm to zero.

Caption 12:19, As with Radial Dual Vibration Monitor, so here also serves to change the monitor output signal to position proximitor thrust / axial monitor.

* If under normal conditions, the thrust position indicated:

- The meter 1.

- Indication lights OK "on" 2.

- Indication lights defeat, alart and danger "off" 3, 4 and 5.

* If the danger set AB switch is placed to the normal position, it will read normal danger point.

* If the danger set AB switch is placed to the normal position, it will read normal danger point.

* If alart set AB switch is placed to the normal position / counter, it will read normal alert set point / counter.

* To determine the output signal can be measured through proximitor proximitor A / B connector on the monitor.

* Defeat toggle switch is used to by-pass him one channel A / B when something is broken.

Figure 12:19 Thrust Monitor

TABLE 1. Fron INDICATOR PANEL, SWITCH, AND CONNECTOR  INDEX no INDICATOR / SWITCH/ CONNECTOR FUNGTION

1 Meter (Zero-Center) Dual Display meter assembly to the thrust position and alert and danger set point for normal and counter directions upon switch selector. Standard meter contains mechanical movement, LED meter indicates measured value by illuminating an LED at the appropriate point on the meter scale.

2 A OK / B and OK (green) Indicator. Illuminated for each channel to indicate feild wiring is intact and operating gap voltage probes are within normal limits.

3 Defeat (Red) Indicator Indicates the channel with OK indicator has been extinguished Defeated (made inoperative).

4 ALERT (Red) indicator Indicates a specific preset alarm level has been thrust excaeded in either the normal or counter direction by either or both channels A and B. Normally set to indicate first warning.

DANGER 5 (Red) indicator

  Indicates a specific preset alarm level has been thrust excaeded in either the normal or counter direction by either or both channels A and B. Normally set to indicate most severe warning.

6 7 DANGER SET AB / AB SET ALERT Toggle Switches

       NORMAL position

       COUNTER position

Used to display the alarm set point thrust in the normal direction for both channels simultaniusly. Is used with normal danger (ND) / normal alert (NA) set potentionmeter normal when adjusting alarm set point.

Same as NORMAL position except for counter direction. Is used with counter danger (CD) / counter alert (CA) SET potentiometer counter when adjusting alarm set point.

8 Prox VERT / Horiz connection. External connection to observe Individual proximitor output signal.

2. Calibrated of DVXY Monitor

A. Tools required for calibration.

1. HP3465A / B Digital Multimeter (DM) 4 ½ digit Digital Multimeter or Fluke 8000 3 ½ digits.

2. TK-3 Bently Nevada Test kalibration (range 0-1000 0-25 mils or mm)

12:20 Picture Card for Thrust monitor

B. Thrust Axial Position Calibration Procedure

1. Set the meter mechnical zero, the condition of power OFF, set the set mechanical zero, is behind the meter indication posisnya see picture 12:20

2. Generate Calibration Signal, refer to paragraph 12.1 Gap calibration voltages representing the mechanical machine zero and full scale monitor (normal direction).

See Table-1, the required voltage on the meter range and transducer type. Calibration is one of them using a micrometer spindle of the TK-3 or variable dc power supply to generate a calibration voltage (voltage calibrator).

3. Adjust the zero (channel A), connected to signal calibration for point 7 (connection on the monitor). release from the recorder before calibration performed. Adjust the input voltage to zero. Adjust zero with a potentiometer, (4) hinga required voltage or current measured between 11 and common TP (meter scale reads zero)

4. Adjust the span and then the meter, Adjust the input voltage represents full-scale. Adjust the span potentiometer A, (9) after the required voltage level is reached or the current is measured between TP 11 and common (meter does not refer to full scale). Adjust the meter calibration potentiometer, (8), for full scale meter dfleksi.

12:20 Block diagram Figure thrus monitor

Caption:
Output proximitor forwarded to;
1. Buffer amplifier (2) proximiter output.
2. Differential amplifier (8) with output amplifier to the appointment of axial movement in normal meter / counter.
3. Output voltage external recorder (9).
4. Alart alarm circuit (11) and danger (12) which serves to compare the output amplifier (8) and (10) to the price of the alarm set point.
5. When the alert / danger set point is exceeded, then the alert / danger indicator lights and activate the relay danger that can be connected to the system trip of turbine / compressor

Figure 12:21 System Overview for system alarm and danger




Axial thrust posistion 12:22 Picture Calibration


Figure 12. 23 Spec. Thrust probe, proximitor and monitor

how to calibrate weights

How To Calibrate A Good Weight - necessary equipment and weights that have been certified by the meteorological agency as an accurate comparison standardized to obtain the actual value, as an example of a calibration tool to pack like a sack of fertilizer, cement bags, and thanks to google

Tools needed to calibrate the scales are certified calibration weights

in this case we use instrumentation tool CB900G as controller type, hbm as sensor type loadcell weighing

1. Press the ENTER key simultaneously for 3 seconds and the SPAN will appear zero press MODE menu to bring up the menu SPAN 0000 provides input the number you want to calibrate to 50.00 kg sample by pressing the transfer function zero and tare digit number to enter the numbers, next step

2. Prepare the weights that have been certified calibration, and insert weights into the bucket scales, if a 10 kg stone value, then enter 10 stone, when the stone was in the bucket scales, then the tool controller CB900G press the ENTER key, the controller will read weights and produce an accurate value of 50 kg

Thus may be useful

instrumentation amplifier

instrumentation amplifier is properly used to describe a category of true differential-input amplifiers that emphasize high common mode rejection (CMR) and accuracy. Although both instrumentation amplifiers and difference amplifiers use op amps as basic architectural “building blocks”, they are distinctly different from their op amp cousins.

Op amps are “single-ended” and they are usually intended to operate in a variety of applications with their feedback determining their functions. Instrumentation amplifiers and difference amplifiers are used primarily to provide differential gain and common mode rejection. Employing feedback from output to input is not intended.

In some instances this term has been widely misused and this has created confusion as to the correct definition of an instrumentation amplifier (IA). In the early days of monolithic operational amplifiers, one well-known vendor referred to their new precision op amp as an instrumentation amplifier. What they meant to say was that it was an “instrumentation-grade” op amp.

In addition, large laboratory bench-top amplifiers and even traveling- wave tube (microwave) amplifiers have been called instrumentation amplifiers. It is not surprising, then, that so much confusion exists about what an IA really is and what it does.

Most common IAs are one of three types: the simple “Difference Amplifier”, the “Two Op Amp Instrumentation Amplifier”, and the “Classical Three Op Amp Instrumentation Amplifier” architecture. As we shall see, these three architectures are interrelated but their performance differs in certain important aspects.  For now, let’s just think of the IA as a “blackbox” differential amplifier.

The Wheat Stone Bridge Sensor

To better understand the instrumentation amplifier and why its high common- mode rejection is so important, let’s take a look at one of the most common transducers in use today the Wheatstone Bridge. While the usual way of depicting the bridge circuit is shown the diagram of Figure 2a, it can be redrawn (Figure 2b) to show that the bridge is nothing more than two voltage dividers driven by a single voltage (Vex) or current (Iex) excitation source.

Conventional & Redrawn Bridge Circuit

Let’s look at an example of a Wheatstone Bridge sensor with zero input stimulus (pressure, temperature, force, etc.):

 

Balanced Bridge Generates CMV But No Differential Output Voltage

 source : www.cypress.com/?docID=38317