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We offer a complete product range of SPL 501 Triac Phase control, TRIAC PHASE CONTROL, Silicon Controlled Rectifier PHASE CONTROL, relaxation oscillator System and POTENTIOMETERIC ERROR DETECTOR
In ac circuits the triac can be turned on at any
angle with respect to the applied voltage
polarity. The angle is oftenly called the firing
angle. Power controlled by this manner is
called full power control. The triac is turned off
when current passed through it becomes zero
during crossover point of the input cycle.
After the SCR the TRIAC is the most widely
used device in power control circuits. A triac is
similar to two SCRs back to back connected.
The basic function of phase control is to
convert an input (ac) voltage to a controllable
output (ac/dc) voltage. The basic principle of
phase control is to control the point in time at
which the thyristors (SCR/TRIAC) are allowed
to conduct during each half cycle. In such
circuits the thyristors can be turned on at any
angle , with respect to the applied voltage
polarity. The angle is oftenly called the firing
angle.
This training board designed to studycharacteristics of unijunction transistor. Theboard contains two equally IC regulated dcpower supplies for base - bar and emitter.Three meters are provided to take readings ofvolt and current. An unijunction transistorconsists a bar of n - type silicone which is lightlydoped, having high ohmic contacts at both sideof the bar. |
This set up is designed to study the time response of
simulated linear systems.
The present set up has straightforward building blocks
of simulated process & signal sources.
A cathode ray oscilloscope (dual trace is best option)
is the only other apparatus required to carried out the
most experiments.
Potentiometric transducers are used in control applications because
of their simplicity. To measure output variables and made comparison
between reference and feedback is quite simpler in these trancducer.
In a position control system the potentiometer type transducer used as
error senser . Any deviation in position of the motor is sensed by R2 in
comparison with the reference provided by R1.
Compensation network are oftenly used to made
appriciable improvement in transient response
and small change insteady state accuracy. This set up
has facilitate to study and designimplemantion of such networks.
Three of such networks are given inthe set up and performance
of other designed networks can be imple-mented using few
passive components.
This set up is designed to study of dc motor
position control system called servomachanism
and comes first in automatic control systems.
The prime advantage of this set up is near
perfection to the simulated sys-tems.
The set up comprises two parts a, the motor unit and b, the control unit.
In industrial applications speed control of
motors is very common require-ment. This
experiment unit is designed to study of speed
control process of a small dc motor. The unit
has following features.
1. Motor unit, which comprises a small
permanent magnet dc motor, rated voltage 12
Vdc, rated current 0.25A at normal run and
0.4A at full load, the torque 75 gm / cm and
maximum speed in excess of 3200 rpm ( open loop )
This experimental set up is designed to studyof a small step-per motor fitted with calibrateddial and servo potentiometer in see throughcabinate. The main unit has a motor controller, pulse sequence generator, variable frequencysquarewave oscillator, single stepmonopulserand wobbling signal to observe dynamicresponse. The unit can be interface with uP kitfeeding appropriate program |
This set up is designed to study of ac motor position control system .The set up comprises two partsa the motor unitb, the control unit.The motor unit : It consists a two phase ac sevomotor.It has the technical specifications as Operating voltage : 120 Vac, maximum current 0.15 Amp.Rated shaft speed : 2400 rpm, Inertia 4.6 x 10-4 Kg / cm2.Torque : 0.085x 10-2 Kg / m. |
The synchro transmitter / receiver demonstrater unit is designed to study of
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The devices used in electrical control system
The relays is an important primary controlelement in a control system which is beingcontrolled by an electrical signal givesadvantage of cost reduction. These systemdeliberately introduced as on - off control.Thisset up is designed to study of such relay controlsystem characteristics. The set up hassimulated relay with simulated process.Therelay : The relay controller system is representin blocks upon the panel |
Light intensity controllers are employed in
studios, in indoor sta-diums and some other
applications where the lumineous intensity is
required to be constant. Basically these are the
close loop systems where the ambient light
condition whatever it is required is sensed by
the transducers and used to control the lamp
intensity by suitable circuits. This set up is
designed to study of such system in labs.
The analog computers are used to solve
the mathematical problem with contineously
variable parameters.
To solve the problem there are some electrical
components are used. The basic components
are operational amplifiers, potentiometers, capacitors,
resistors and switches. The operational amplifier is
used as an inverter, summer, multiplier and integrater
using the passive components abovesaid.
The digital control systems are going populartoday because of readily available inexpensivemicrocomputers and peripheral devices. Adigital controller has versatility to change ormodify its control function by changing ormodifying its program instructions (in analogcontrollers it is modified by changing itshardware). In other words digital controller hasdistinct advantage over analog that it can bemodified by software only where in analogworld it is hardware only. |
The synchro transmi tter / receiver
demonstrator unit is designed to study of
remote transmission of position in AC servo
mechanisms. These are also called as torque
transmitter - receiver. The unit has one pair of
transmitter - receiver synchromotors, powered
by an isolated ac inbuilt supply.
In industrial control systems, information about physical
process should beknown and tranducers play vital role in
it. A transducer is a device whichconvert one form of energy
into other form. In other words it convert one'ssignal form into
other signal form. To measure temperature in industries
thermocouples are widely used. This set up is designed to study
of temperaturemeasurement using type j thermocouple.
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The V.S.I. (voltage source inverter) drive is onemethod to obtain the variable frequency voltageto control speed/torque of induction motor .The three phase 'cage induction motor' of fractionHP, is used in this application. In these motors toset up the air gap flux, magnetic current must flow, as lagging the voltage by 1200. The movement of therotation flux across the conductors induces a voltagein the 'short circuited closed cage' rotor winding, hence causing current flow. |
Acceleration / deacceleration of dc motor required
to meet the speed / torque demand or steady - state
operation. The acceleration demand is fulfilled
with controlled drives (in most case close - loop),
and deacceleration complied with electrical or mechanical
breaking. The breaking produce a torque in a direction to
oppose the motion. The steady - state operation is obtained
at a speed for which breaking torque equals the load torque.
DC servomotor has been the prime mover
element most widely used in control
applications. In position control the DC
servomotor is of the highest choice due to
simple control circuitry. These motors suffers
from wear and tear because of brush and
commutator. Generally the DC motor is
controlled by armature control via a dc servo amplifier.
The given drive works upon live ac sourcewhich provide ac supplies to the fractional H.Psynchronous motor through converters configurratedas half bridge cycloconverter. The complete system isblock printed upon the panel. The frequency control ismade continuously variable from > 25Hz down to 6 Hz approxto understand drive principle. |
The presented board is designed to study of opto - devicessuch as photo conductive cell ( light dependend resistor), photo transistor, photo diode (pin diode), and photo voltic cell electrical (V - I) characteristics.The light source is 12V21W tungston filament lamp, powered by variableregulated dc supply ( 0 - 10V, 2Amp). One regulated dc supply upto 19voltwith two dual range digital panel meters. There is a 3 way selector, used toselect the meters interconnections to take readings of lamp voltage, dc supplyvoltage and current and photo cell voltage and current. |
A photo resistor consists of a device that change its electrical
Ohmic resistance when light is applied. Thus it is also called
as photo conductive cell or the Light Dependent Resistor abb.
L.D.R. The active region of photo resistor is a thin film of cadmium,
selenium, a metalliic helide or a metallic sulphide. When these type
of materials are exposed to the light radiation, free electrons are
created as photon energy drives them from a valence
band into the conduction band.
SPEED CONTROL OF INDUCTION MOTOR (VARYING VOLTAGE) |
The set up has built in see through top cover
in MS powder coated cabinet. The control
circuitry is given upon the front panel and
sockets are given to observe the motor
voltage and current waveforms. Since it is a
line operated unit thus isolation is provided by
small transformer at the observation points.
This demonstration unit use the small
induction motor 220V.
This set up is designed to study of load cell utilization as
level measuring transducer. The set up consists a load cell,
water container, the signal conditioner circuit and a digital
display calibrated for level measurment. The set up have
its own inbuilt regulated dc supplies.
WATER BATH INCUBATOR SHAKER (Metabolic Shaking Incubator) Useful for studies on tissue metabolism, enzymes and protein coagulation and other experiments demanding shaking at constant speed under controlled temperature conditions. Double walled construction, inner chamber made out of thick highly polished stainless steel sheet and outer made out of thick mild steelduly finished in stoving enamel paint. The lid is made of stainless steel. The gap between the two chambers filled with glass wool to prevent loss of heat. The temperature is achieved by superior immersion heater and is controlled by capillary type thermostat from ambient to 90oC+ 0.5oC.The shaking mechanism is fitted with variable speed motor couple to shaking tray working on rollers. Shaking speed is controlled from tray working on rollers. Shaking speed is controlled from 40 to 140 cycles per minute. Shaking tray can hold either test tubes or flasks of 25ml. or 100ml. capacity. Front panel includes on-off switch, shaking mechanism indicator, speed control, thermostat control etc. L-shaped thermometer is provided to indicate inside temperature. Equipment to work on 220V AC 50Hz single phase. Shaking Tray Size (Stainless Steel) Capacity a. 275x275x150mm 12ltrs. b. 405x300x150mm 18ltrs. Optional :- i) Digital Temp. Indicator. ii) Digital temp. Indicator- Cum- Controller. iii) Microprocessor PID digital temp. Indicator Cum- Controller. iv) Shaking tray for 25ml, 50 ml, 100ml. 250ml & 500 ml & 25mm dia. Test tubes or Conicalflaks. |
In many applications variation in speed of
electric drives is essential. As in process
industries the speed control of motors in
different stages are required. The introduction
of thyristors solves these problem efficiently ,
due to simple control action and capabilities of
phase control. The fast response, reliability
and less cost dominate this scheme very
popular today.
Switching a thyristor on, is called its triggering
or firing. As we know that current flows in a
SCR when it is in ON state. There are many
methods bywhich a SCR can be triggered, but
the most widely used is 'gate trigger method'.
The gate triggering is most common in
practice. In lab practicals we trigger the SCR at
different gate current magnitudes to obtain
forward breakover voltage earlier than its VBo.
THYRISTOR CIRCUIT BREAKER CURRENT LIMITING |
In simple circuit breaker system relays areused to control on - off. In these days thyristorsare used for the same system. The property ofa SCR is to latch, when it can be triggered byan input gate current, when its anode is +vethan its cathode. The SCR get turn off by breakingthe anode current producing anode current below a value IH. |
This kit is designed to study of low capacityMosfet based inverter system. It has inbuiltdrive signal source, switching device, fixedresistive load in form of three lamps and dcsupply for the set up. The circuitry is representedin two subsystem.The working principal of Mosfetinverter is quite simple. |
This kit is designed to study step down chopperbased upon MOSFET. The power circuitryconsists of a mosfet to give dc output < input dcsupply. The variable pulse width generatorused to control the mosfet switching period, hence to control the output voltage. |
In ac circuits the SCR can be turned on at anyangle a with respect to the appllied voltagepolarity. The angle is oftenly called the firingangle. Powercontrolled by this manner iscalled half control. The control element iscalledtrigger circuit. The SCR firing angle maybe controlled using passive com-ponents suchresistor and resistor - capacitor combination. |
A flip - flop is a bistable circuit inwhich the one's
output remain in stable state till the complement
stage is triggered to change the state. A bistable
is also called the latch. The commonSCRis a good
latch device and useful to make bistables. But it has
a disadvantage that it can't be retriggered to change
the state (cut - off ).
The low voltage ac voltage ( S1 of T ) is appliedto the pair of two SCRs, CR1 and CR2, connected antiparallel with in series RL.These are the main SCRs. As the SCR is beingcommutated at the crossover points of accycle, but then it becomes a simple phasecontrol circuit. To commutate them earlier atrequired time two auxiliary SCRs, CR3 and CR4 are use. |
S.C.R. PARALLEL INVERTERTO DRIVE AC INDUCTION MOTOR |
The kit is designed to study SCRparallel inverter driven small acinduction motor. The kit consistsinverter transformer, 2 SCRs, oneinductor, one commutation capacitor, one small ac induction motor, triggercircuitwith variable frequency |
Power electronics labPulse transformer & optocoupler technique |
Pulse transformers are used to couplea trigger pulse generator to a thyristorin order to obtain isolation between twocircuits. Generally these are woundupon a ferrite cored bobbin, in 1 : 1 ratio( NP: NS), to couple one thyristor, or 1 :1 : 1fashion to couple a pair of thyristors. In givenexperimental board it is in 1 : 1 form. |
In ac circuits the SCR can be turned on at any
angle with respect to the applied voltage
polarity. The angle is often called the firing or
delay angle. In other words 'in order to control
the output voltage of thyristor controlled
converter, it is necessary to control the phase
of the thyristor firing pulses'.
In industrial control systems, information about
physical processshould be known and tranducers
play vital role in it. A transducer is adevice which convert
one form of energy into other form. In other words it
convert one's signal form into other signal form. In industrial
applicationthermistors are used to control low temperature.
This set up is designed to study of SCR based
Jones chopper system. It has inbuilt trigger
source, SCR chopping device with
commutation circuit, a fractional HP dc series
motor as load and unregulated full wave
rectified dc supply for the set up.
The function of a drive circuit is to switch powerdevice (BJT, MOSFET, IGBT) from the off stateto on state and vice versa. In most cases adrive circuit used to minimize the turn - on andturn - off time, so the power device take littletime in traversing the active regionto enhancethe speed and operating frequency. |
A chopper can be used as switched moderegulator, which convert a dc voltage (eitherfrom unregulated or fixed dc source) into avariable regulated dc output voltage |
DC to DC converters are self commutatedchoppers in which current extinction, or may beturn off accomplished by gate pulse control ofthe device. These choppers utilize self -commutated devices such as MOSFET, IGBT, BJT or GTO's to transfrom DC voltage fromone level to another |
Speed measurement in process industry is
very common in which shaft, pulley or gear
rotation ismeasured by many techniques. This
set up is designed tomeasure speed of a motor
shaft by an electromagnetic transducer.The
electromagnetic transducer is similar to an
electromagnet system. It is an electro-magnet
(the wounded coil) is energized with
amagnetic substancewhich is kept outside the
coil cause to flow mmf.
The provided set is designed to study of capactive transducer.
It has inbuilt excitation source, signal processing circuitry and
a digitalpanel meter which can be adjusted to read displacement
in 0. The setup has a ppc dielectric PVC ganged capacitor as
transducer. Completeprocess is well printed in blocks with
test points in form of sockets to observe/ measure waveforms.
In some applications speed control of acinduction motor is required. The speed of an acmotor can be controlled by varying either theamplitude or the frequency of its supplyvoltage, or both. The variable voltage, fixedfrequency technique has the advantage of itslower cost. When the close loop monitorsystem is used. |