Satish Brothers punjabi mohaala, Bahadurgarh, Haryana

The Wheatstone bridge is one most important bridge for measurement of Resistance. The present bridge consists four resistance dials in standard arm(S ), having known non - inductive resistance as x1K, x100, x10 and x1 + 1%. dials to obtain balance. The last dial is a continuously variable having resolution of 0.2. One ratio arm P has a fixed non inductive resistance of 1000ohm,

Power Source : Electric

Standard double wall construction, inner being of stainless steel outer of m.s. duly stoving paint finish and gap filled for temp. insulation with glass wool.Top cover with 75 mm (3") holes with concentric rings. Temp. range 5oC above ambient to 95oC type element with accuracy of + 1oC. Supplied complete with plug & cord. Panel provided with pilot lamps, thermostat control knob etc.   Size inside (Stainless Steel)        Capacity Approx.   a) 300x250x100mm 6 holes of 75mm dia .       8ltrs. b) 355x405x100mm 12 holes of 75mm dia.      15 ltrs.   Optional:-   i)       Imported thermostat EGO/ JUMO German with the accuracy of ±0.5°C. ii)      Digital temp. Indicator- Cum Controller. iii)      Microprocessor PID Digital temp. Indicator-Cum Controller. iv)     Digital Temp. Indicator.

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 Conical               flaks.   

VACUUM PUMP Motor driven, oil sealed pump mounted on heavy base. It is driven by V belt at speed upto 400 RPM. Choice of single and double stage available creating Ultimate vacuum of 0.01 mm of Hg column and 0.0 mm of Hg column respectively. The pump is to work on 220V AC 50 Hz single phase Capacity Motor a. 32 liter/mm 0.25 hp I) Single Stage. ii) Double Stage. b. 50 liter/mm 0.25 hp I) Single Stage. ii) Doubles Stage c. 75 liter/mm 0. 25 hP I) Single Stage. ii) Double Stage d. 100 liter/mm 0. 50 hp I) Single Stage. ii) Double Stage Optional :- i) Vacuum Gauge with regulator. ii) Belt guard iii) Moisture Trap. iv) Non-returnable value. v) Air Ballast.

UNIVERSAL MOTOR SPEED CONTROL USING PHASE CONTROL (STROBOSCOPIC METHOD)   This set up is designed to study of speedcontrol (in open & close loop) of universalmotor using phase control system. It has inbuilttrigger source, thyristor phase control circuit,speed measurement & tachgeneration .Afraction HP universalmotor coupled with an ac induction motor, which is used to impose load to found characteristics of controller.

For experimentally verifying the laws of triangle, parallelogram and polygon of forces.  Comprising of a circular 40 cm. diameter  aluminum disc, graduated into 360 degrees. Complete with leveling screws, clamping devics to fix the table at any desired angle, five sliding clamp pulleys, central, ring string and five sets of iron nickelled slotted weights, each set containing nine weights and one hanger of 50gms. Each.

The set up is designed to study of SCR based dc chopper system to control and regulate dc motor speed.It has inbuilt trigger ( oscillator) source, SCR chopping device wi th commutation circuit, a fraction HP universal motor with a small dc motor as tacho generator and Unregulated dc supply for the set up.

In ac circuits the SCR can be turned on at anyangle with respect to the applied voltagepolarity. The angle is often called the firing ordelay angle. In other words 'in order to controlthe output voltage of thyristor controlledconverter, it is necessary to control the phaseof the thyristor firing pulses'.

 A Single pan,low form balance that has three notched beam with centreindicating sliding masses with total wieghing

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.  

In ac circuits the triac can be turned on at anyangle with respect to the applied voltagepolarity. The angle is oftenly called the firingangle. Power controlled by this manner iscalled full power control. The triac is turned offwhen current passed through it becomes zeroduring crossover point of the input cycle.After the SCR the TRIAC is the most widelyused device in power control circuits. A triac issimilar to two SCRs back to back connected.

This set up is designed to study of strain gauged load cellutilization as torque measuring transducer. The set up consists a straingauge bridge, the signal conditioner circuit and a digital display calibratedfor torque / angle measurment. The set up have its own inbuilt regulateddc supplies  

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 +ve than its cathode. The SCR get turn off by breaking the anode current producing anode current below a value IH.  

SED 2104                 The V.S.I. (voltage source inverter) drive is one method to obtain the variable frequency voltage to control speed/torque of induction motor .The three phase 'cage induction motor' of fraction HP, is used in this application. In these motors to set up the air gap flux, magnetic current must flow, as lagging the voltage by 1200. The movement of the rotation flux across the conductors induces a voltage in the 'short circuited closed cage' rotor winding, hence causing current flow.

SPEED CONTROL OF FHP SYNCHRONOUS MOTOR USING THREE PHASE VSI INVERTER. SED 2100                 The variable frequency drive for synchronous motor,has advantage over variable voltage such as,(1) to vary speed in stepless manner(2) to maintain constant torque/power(3) to run motor on slower/ higher speed than ratedThe V.S.I. (voltage source inverter) drive is one methodto obtain the variable frequency voltage to control speed/torque of Synchronous motor

The kit is designed to study three phase full wave fully controlled bridge converter output characteristics. The kit consists isolated three transformers 230 : 120 Vac, 1 amp prewired for star - delta formation, firing angle control circuit having three synchronisation transformers with six 400Vac6AS.C.R. wired in 3 phase full wave bridge converter configuration. One small time constant inductance added as LR load, and lamp (100W) as resistive load.

The kit is designed to study three phase fullwave fully controlled bridge converter outputcharacteristics. The kit consists isolated threetransformers 230 : 120 Vac, 1 amp prewired forstar - delta formation, firing angle control circuithaving three synchronisation transformerswith six 400Vac/6AS.C.R. wired in 3 phase fullwave bridge converter configuration. Onesmall time constant inductance added as LRload, and lamp (100W) as resistive load.

The given drive works upon live ac source which provide ac supplies to the fractional H.Psynchronous motor through converters configurrated as half bridge cycloconverter. The complete system is block printed upon the panel. The frequency control is made continuously variable from > 25Hz down to 6 Hz approx to understand drive principle.  

THREE PHASE BRIDGE CYCLOCONVERTER A cycloconverter oftenly called as 'cycleconverter' changes the frequency of a single (or three phase ) alternating power sourcewithout the necessity of an intermediate ac todc conversion stage. A cycloconverter requiremultiple control device of a single or threephase excitation, and are limited to low outputfrequency only.

 Test tube are made from borosilcate glass in following capacity  

Size : 5ml 10ml 25ml

The synchro transmitter / receiver demonstrater 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 synchro motors, powered by an isolated ac inbuilt supply. Sockets are brought upon the panel to make connections with attenuated compensated output in ratio of 1 : 10 for waveform observation. The synchro pair is well mounted inside steel cabinate and dials printed in degrees with resolution of 20 provided to study phase / displacement errors. The control knobs are factory adjusted for electrical zero and procedure is given in last page if recorrection required due to transportation.Complete unit is 220 volt ac main operable.

Country of Origin : India

The synchro transmitter receiver demonstrater 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 synchro motors, powered by an isolated ac inbuilt supply. Sockets are brought upon the panel to make connections with attenuated compensated output in ratio of 1 : 10 for waveform observation. The synchro pair is well mounted inside steel cabinate and dials printed in degrees with resolution of 20 provided to study phase displacement errors. The control knobs are factory adjusted for electrical zero and procedure is given in last page if recorrection required due to transportation.Complete unit is 220 volt ac main operable.

Switching a thyristor on, is called its triggeringor firing. As we know that current flows in aSCR when it is in ON state. There are manymethods bywhich a SCR can be triggered, butthe most widely used is 'gate trigger method'.The gate triggering is most common inpractice. In lab practicals we trigger the SCR atdifferent gate current magnitudes to obtainforward breakover voltage earlier than its VBo.

A stroboscope is an instrument, which flashesthe light upon rotating or vibrating object whichis turning at high speeds, cause to appear it tobe standstill ormoving slowly. It is non - contactspeed measuring instrument.In stroboscope principle, intense light flash of variant frequency is directed towards the rotatingobject. When the flash rate is equal to or multiple of the rotating revolution it may be standstill.