At ISC the fully qualified and skilled employees make it possible to develop high quality engineering
solutions and products using latest technologies.
- Ozone Generating Units
Ozone kills the bacteria and viruses safely and effectively.
Ozone in sufficient concentration will eliminate or greatly reduce the odour and colour in the treated water.
Elimination of all the toxicity due to chlorine by products which may present in the water.
There will no eye irritation and hair falling problems like in case of chlorine treated pools.Ozone is generated on premises.
(No storage, procurement and transport required).
There is no toxic byproducts produced.
Ozone treatment is the best eco friendly system available today for the disinfection purpose.
Ozone treatment increases the dissolved oxygen in the water which is very good for the swimmer.
Ozone is the most active oxidizing agent that can be used safely.
It is sometimes called “activated oxygen”, or enriched oxygen.
The reaction of ozone is immediate and it takes few seconds only to kill the microorganism.
Hence complete disinfection is possible by having a short contact time of1to 3 minutes.
Tests have proven that Ozone is 3000 times more active in the destruction of bacteria and viruses than chlorine in the same concentration.
Escherichia (E-coli) is destroyed within 15 seconds by ozone at a concentration of 1mg/liter (1 ppm) Since ozone is very unstable and does not remain as
residual a small quantity of chlorine is to be added after ozonation to maintain the residual disinfectant in the water.
This chlorine will remain as residual since ozone has oxidized the organic molecules.
- A/C Control Units for Automotive
Any AC works on the same principle of Physics and Gas particles: when gas is compressed it heats up and when suddenly released,
it cools down and in doing so absorbs the heat of the ambient. In an AC, there is a compressor, the compressing area coils and the expansion area coils.
The compressor compresses the special gas in the compression coils which get heated up.
These coils are located on the outside. The compressed gas is then suddenly released in the expansion coils located on the side of the chamber/room that is supposed to be cooled.
The expanding gas cools down the coil to near freezing. Both coils are covered by a radiator grill that helps in dissipating heat/cold faster.
A fan also exists in the AC that blows air over the expansion coils radiator driving hot air outside the room.
The same fan sucks in cool air over the cooling coils radiator and then blows the cold air back into the room.
This is the basic principle and applies to all ACs and Refrigerators.
Train ACs also work on the same way. The only difference is that the home AC works on home electrical supply (230 V or 110 V Alternating Current) whereas the AC on the train (as also in the car) works on 12 V DC supplied by the dynamo and batteries.
In the car, the AC compressor shuts off when the car engine is switched off. This is because the car battery is not powerful enough (in AH rating) to run the AC compressor for a long time. It would drain the battery completely within 5 to 15 minutes.
However, the fan continues to run if AC is switched on without compressor.
On Indian trains, there are ICF AC coaches and LHB AC coaches.
ICF AC Coaches: In ICF AC coaches, the AC compressor switches off when the train has come to a halt but the fan continues to operate on battery power. ICF coaches that are self powered by dynamo and battery under the coach. But prestigious trains like Rajdhanis, Shatabdis, Durontos (in their previous ICF rakes), as well as some trains that carried a lot of AC coaches - like the Mumbai-Ahmedabad Gujarat Mail having 11 AC coaches and the highest number in a non-AC train - needed a generator car to continuously supply electricity even when stationary. So such trains had/have a generator car at each end of the rake. (The Mumabi-Ahmedabad Gujarat Mail now uses all LHB coaches).
LHB Coaches: The LHB coaches are different. Their internal electricals work on 230V AC. But they are not self powered, i.e., there is no alternator or battery+invertor below the coach. Indian Railways have not yet developed the mechanism to step down the 25 KV AC power to 230V AC (at the locomotive) and deliver the power the coaches. As also, the whole rail system is not electrified and there is no place for installing a generator in a Diesel Loco.
The LHB train thus must have a generator car. The generator car is located at the two ends of the rake.
Hence AC coaches in LHB rake continue to run the compressor and cool even when the train has halted.
The fresh air comes in through the air inlet of the AC unit. The conditioned air is transported in heat insulated aluminum ducts mounted below the roof and distributed through the perforated ceiling into the passenger room.
The return air flows back through openings above the compartment door to the AC unit. The entrance area, toilets and pantry are connected to the exhaust system[1] .
- High Resolution ADCS
Designers' seemingly insatiable appetite for higher resolution and faster conversion speed has spawned a new generation of A/D converters that provide a flexibility not previously available. The new 22-bit converters combine high accuracy, an extremely wide dynamic range, and microprocessor compatibility in a modular package. These features make them an attractive alternative to bulky benchtop DVMs. In addition, new oversampling techniques have significantly reduced the cost of 16- to 20-bit converters over those using more traditional techniques.
Three manufacturers currently offer oversampling (also known as sigma-delta and delta-sigma) converters and others are planning to enter the market soon (see box, "Converters couple analog and digital filtering"). Many of the manufacturers of high-resolution products are mainstream players in the data-converter marketplace. Analog Devices, Analogic, Burr-Brown, and Micro Networks all have experience designing high-resolution ADCs. However, Thaler Corp's first converter is a 20-bit high-accuracy ADC, and Motorola has entered the field with an oversampling converter. Prema Precision electronics, a West German manufacturer of precision multimeters, produces a 25-bit ADC that is the highest-resolution converter available. These high-resolution converters are dedicated ADCs, not products that include internal ADCs and DACs and function as analog interface circuits.
According to many ADC manufacturers, the main reason for the movement toward higher and higher resolution is that data-acquisition-system designers want to make use of every bit of their transducers' resolution. They feel that if there has to be a limiting factor in the system it should be the transducer, not the ADC. Another reason is that higher-resolution converters can provide additional and often critical details about a set of data.
Ensuring the accuracy of this data is a very tough design task. Even a small amount of system noise can corrupt a high-resolution converter's data. The usual solution to this problem is careful layout and grounding, which will improve systems accuracy to the limits of the ADC. However, it's difficult to find a truly accurate 16-bit converter. Many 16-bit converters, for instance, have only 14 bits of accuracy. This level of accuracy is especially true of many of the successive-approximation types. Although a converter's integral nonlinearity may be 14 bits (equivalent to ±0.003% FSR), it may still provide no-missing-codes performance at 16 bits. Note that the linearity of some 14-bit ADCs matches that of many of the 16-bit products.
The world of high-resolution A/D converters is somewhat fragmented. Many converters are intended for very specialized markets. The successive-approximation converters serve many general-purpose data-acquisition systems. Other converters are closely tied to specific applications. Fortunately, every converter fits into one of two general classifications: those designed for the highest-possible dc accuracy in the dc sense, and those designed for signal processing and good ac specs. Two general applications are associated with these categories: precise measuring systems and DSP applications.
Many oversampling converters are intended for signal-processing applications, therefore their data sheets usually quote complete dynamic specifications. But this trend isn't confined to oversampling converters. As DSP applications proliferate, so does the number of high-resolution converters specifically aimed at these applications. To help designers evaluate and compare converters' ac performance, many new converters are fully tested and specified for dynamic characteristics such as S/N ratio and THD.
For applications that require the highest possible dynamic range, take a look at the high-resolution integrating converters. These high-accuracy converters are a world unto themselves. ATE, process control, and weighing systems are typical application areas for them. These ultrahigh-resolution converters are also used in medical and scientific instrumentation that must be able to distinguish extremely small differences in element or chemical concentrations.
- RMPU Monitoring Systems
It will monitors each and every phase of operations in the railways coaches, it will helps to find out problems occurred in coaches.
The Microprocessor Controller consists of one Control Unit and one Display Unit. Control Unit monitors and controls the sub systems of two RMPUs by sensing different temperatures like Return-Air temperature, Fresh-Air temperature, Supply-Air temperature and Humidity of the Return-Air etc. by means of various sensors fitted in RMPUs.
It also continuously monitors the health of RMPUs and the log of events is stored in “Event Recording System” , while the list of faults are stored in “Fault Storage System”. The Events & Faults stored in memory can be downloaded through USB port by inserting the USB drive. The health status of the subsystems are also displayed by the glowing LEDs provided on the Control Unit.
Display Unit, as a part of the Microprocessor Controller, consists of a graphical LCD and few navigation keys. It is used to display Date, Time, Coach Number, RMPU Number and Make, Status of the RMPU’s sub-systems, various temperature set points etc. It enables to change the defaults settings of the above mentioned parameters through navigation keys. The messages displayed on the Display Unit are under the control of Control Unit.
The communication between the Control Unit and Display Unit is through an RS-232 port. RS-485 Communication Port is also provided for GSM/GPRS connectivity for centralized control, as a future requirement.
- Battery Charges
Charge and discharge rates are often given as C or C-rate, which is a measure of the rate at which a battery is charged or discharged relative to its capacity. The C-rate is defined as the charge or discharge current divided by the battery's capacity to store an electrical charge. While rarely stated explicitly, the unit of the C-rate is h−1, equivalent to stating the battery's capacity to store an electrical charge in unit hour times current in the same unit as the charge or discharge current. The C-rate is never negative, so whether it describes a charging or discharging process depends on the context.
For example, for a battery with a capacity of 500 mAh, a discharge rate of 5000 mA (i.e., 5 A) corresponds to a C-rate of 10 (per hour), meaning that such a current can discharge 10 such batteries in one hour. Likewise, for the same battery a charge current of 250 mA corresponds to a C-rate of 1/2 (per hour), meaning that this current will increase the state of charge of this battery by 50% in one hour.[3]
Since the unit of the C-rate is typically implied, some care is required when using it to avoid confusing it with the battery's capacity to store a charge, which in the SI has unit coulombwith unit symbol C.
If both the (dis)charge current and the battery capacity in the C-rate ratio is multiplied by the battery voltage, the C-rate becomes a ratio of the (dis)charge power to the battery's energy capacity. For example, when the 100 kWh battery in a Tesla Model S P100D is undergoing supercharging at 120 kW the C-rate is 1.2 (per hour) and when that battery delivers its maximum power of 451 kW, its C-rate is 4.51 (per hour).
All charging and discharging of batteries generates internal heat, and the amount of heat generated is roughly proportional to the current involved (a battery's current state of charge, condition / history, etc are also factors). As some batteries reach their full charge, cooling may also be observed.[4] Battery cells which have been built to allow higher C-rates than usual must make provision for increased heating. But high C-ratings are attractive to end users because such batteries can be charged more quickly, and produce higher current output in use. High C-rates typically require the charger to carefully monitor battery parameters such as terminal voltage and temperature to prevent overcharging and so damage to the cells. Such high charging rates are possible only with some battery types. Others will be damaged or possibly overheat or catch fire. Some batteries may even explode.[citation needed] For example, an automobile SLI (starting, lighting, ignition) lead-acid battery carries several risks of explosion.
A simple charger works by supplying a constant DC or pulsed DC power source to a battery being charged. A simple charger typically does not alter its output based on charging time or the charge on the battery. This simplicity means that a simple charger is inexpensive, but there are tradeoffs. Typically, a carefully designed simple charger takes longer to charge a battery because it is set to use a lower (i.e., safer) charging rate. Even so, many batteries left on a simple charger for too long will be weakened or destroyed due to over-charging. These chargers also vary in that they can supply either a constant voltage or a constant current, to the battery.
Simple AC-powered battery chargers usually have much higher ripple current and ripple voltage than other kinds of battery chargers because they are inexpensively designed and built. Generally, when the ripple current is within a battery's manufacturer recommended level, the ripple voltage will also be well within the recommended level. The maximum ripple current for a typical 12 V 100 Ah VRLA battery is 5 amps. As long as the ripple current is not excessive (more than 3 to 4 times the battery manufacturer recommended level), the expected life of a ripple-charged VRLA battery will be within 3% of the life of a constant DC-charged battery.[5]
Fast Charger: Fast chargers make use of control circuitry to rapidly charge the batteries without damaging any of the cells in the battery. The control circuitry can be built into the battery (generally for each cell) or in the external charging unit, or split between both. Most such chargers have a cooling fan to help keep the temperature of the cells at safe levels. Most fast chargers are also capable of acting as standard overnight chargers if used with standard NiMH cells that do not have the special control circuitry.
Three Stage Charger To accelerate the charging time and provide continuous charging, an intelligent charger attempts to detect the state of charge and condition of the battery and applies a 3 stage charging scheme. The following description assumes a sealed lead acid traction battery at 25 °C. The first stage is referred to as "bulk absorption"; the charging current will be held high and constant and is limited by the capacity of the charger. When the voltage on the battery reaches its outgassing voltage (2.22 volts per cell) the charger switches to the second stage and the voltage is held constant (2.40 volts per cell). The delivered current will decline at the maintained voltage, and when the current reaches less than 0.005C the charger enters its third stage and the charger output will be held constant at 2.25 volts per cell. In the third stage, the charging current is very small 0.005C and at this voltage the battery can be maintained at full charge and compensate for self-discharge.
Induction-Powered Charger Inductive battery chargers use electromagnetic induction to charge batteries. A charging station sends electromagnetic energy through inductive coupling to an electrical device, which stores the energy in the batteries. This is achieved without the need for metal contacts between the charger and the battery. Inductive battery chargers are commonly used in electric toothbrushes and other devices used in bathrooms. Because there are no open electrical contacts, there is no risk of electrocution. Nowadays it is being used to charge wireless phones.
Intelligent Charger A "smart charger" should not be confused with a "smart battery". A smart battery is generally defined as one containing some sort of electronic device or "chip" that can communicate with a smart charger about battery characteristics and condition. A smart battery generally requires a smart charger it can communicate with (see Smart Battery Data). A smart charger is defined as a charger that can respond to the condition of a battery, and modify its charging actions accordingly.
Some smart chargers are designed to charge:
"smart" batteries with internal protection or supervision or management circuitry.
"dumb" batteries, which lack any internal electronic circuitry.
The output current of a smart charger depends upon the battery's state. An intelligent charger may monitor the battery's voltage, temperature or time under charge to determine the optimum charge current and to terminate charging.
For Ni-Cd and NiMH batteries, the voltage across the battery increases slowly during the charging process, until the battery is fully charged. After that, the voltage decreases, which indicates to an intelligent charger that the battery is fully charged. Such chargers are often labeled as a ΔV, "delta-V," or sometimes "delta peak", charger, indicating that they monitor the voltage change.
The problem is, the magnitude of "delta-V" can become very small or even non-existent if (very) high[quantify] capacity rechargeable batteries are recharged.[citation needed] This can cause even an intelligent battery charger to not sense that the batteries are actually already fully charged, and to continue charging. Overcharging of the batteries will result in some cases. However, many so called intelligent chargers employ a combination of cut off systems, which are intended to prevent overcharging in the vast majority of cases.
A typical intelligent charger fast-charges a battery up to about 85% of its maximum capacity in less than an hour, then switches to trickle charging, which takes several hours to top off the battery to its full capacity
- DRB’s
Decade boxes are test instruments which use a series of resistors, capacitors, or inductors to simulate very specific electrical values. They can be quickly and easily substituted into a circuit and replace any standard value component. Their ability to be configured to nearly any resistance, capacitance, or inductance makes decade boxes a convenient way to find the optimum value for circuit operation. Highly useful for laboratory, education, or design work; decade boxes are also ideal for verifying the accuracy of test equipment prior to use as well as troubleshooting in the field or on the factory floor.
The Technology of Decade Boxes
Decade boxes are passive devices that consist of switches and, depending upon the type of box, a series of resistors, capacitors, or inductors of different values arranged to form “decades”. Decades are set up in factors of ten and stepped such that any value 0 through 9 can be selected. For example, a resistance decade box may have a 5 ohm resistor, a 2 ohm resistor, and two 1 ohm resistors in the first decade. The second decade may have a 50 ohm resistor, a 20 ohm resistor, and two 10 ohm resistors. The third decade may have a 500 ohm resistor, a 200 ohm resistor, and two 100 ohm resistors. With this combination, this three decade box can be switched to any value from 1 ohm to 999 ohms in 1 ohm steps. Some decade boxes may have 6 or more decades to allow for very wide ranges and highly precise values. Decade boxes are characterized by their range, maximum resolution, and accuracy.
Using a decade box for testing consists of setting the box to the desired value and hooking up the input device such as a transmitter, controller, multimeter, etc. The display value of the input device should match the set value of the decade box. It’s that simple.
Types of Decade Boxes
Resistance Decade Boxes
Resistance is the opposition to the passage of an electric current through an electrical conductor. Measured in ohms, and defined by Ohm’s Law as equal to voltage divided by current, resistance is one of the most basic of electrical measurements. As it impedes the flow of electricity, resistance is responsible for some power loss across a circuit. That power is lost as heat which can melt wires, creating a fire hazard, if the resistance is beyond the rating for the wires.
There are a number of practical applications that rely on the properties of resistance. Resistance is what keeps our bread toasted because of its ability to create heat out of electricity. Resistance is also used in potentiometers to perform a number of tasks including controlling the volume of audio equipment. Since the temperature of metals and semiconductors affects their resistance, resistance-based temperature sensors such as RTDs are used widely. As so many applications are based on electrical resistance, it’s important that devices that read or rely upon resistance are periodically tested.
Resistance decade boxes can quickly and accurately simulate resistance for quickly testing the accuracy of thermostats, temperature controllers, multimeters, and others. Resistance decade boxes are also commonly used commonly used for product design as they can be easily inserted into a circuit and function as a resistor of any value (within its range) to assist in identifying the optimal resistor size for the circuit.
Capacitance Decade Boxes
Capacitance is the ability of a body to store an electrical charge. Measured in farads, capacitance is important in a number of applications. Capacitance in electric circuits is deliberately introduced by a device called a capacitor. Capacitors generally consist of two conductive plates separated by a dielectric. Capacitors store the electrical charge in the form of an electrostatic field between the plates.
As they are capable of storing electrical current, capacitors are often used in electronic devices to maintain power in case of an interruption to prevent the loss of information from a volatile memory. That same power storage can be used to assist in starting certain types of electric motors or to power amplifiers in audio systems. They are also widely used in electronic circuits for blocking direct current while allowing alternating current to pass. Other applications for capacitors include power factor correction, signal coupling, tuned circuits and many types of sensors.
Capacitance decade boxes can quickly and accurately simulate capacitance for quickly testing the accuracy of multimeters and other instruments that measure capacitance. Capacitance decade boxes are also commonly used for product design as they can be easily inserted into a circuit and function as a capacitor of any value (within its range) to assist in identifying the optimal size for the circuit.
Inductance Decade Boxes
Inductance is an electrical property by which voltage is induced in a circuit, or a nearby circuit, by a changing magnetic field. Measured in henrys, inductance can be classified as self-inductance when the voltage is induced in the circuit itself, or as mutual inductance when the voltage is induced in a nearby circuit. Inductors are the devices that are characterized by their inductance. Inductors are made of a conductor, often a wire, wound into a coil. When current passes through the inductor, energy is stored temporarily in a magnetic field in the coil. Any change to the current passing through the inductor induces voltage in the conductor according to Faraday’s law of electromagnetic induction, which opposes the change in current that created it.
Inductors are commonly found in analog circuits and signal processing. When used in conjunction with capacitors, inductors form tuned circuits which filter out or emphasize specific signal frequencies—critical for radio reception as well as filtering signal interference. Two or more inductors in mutual inductance form a transformer, a fundamental component of every electric utility power grid.
Inductance decade boxes can quickly and accurately simulate inductance for quickly testing the accuracy of multimeters and other instruments that directly measure inductance. Inductance decade boxes are also commonly used for product design as they can be easily inserted into a circuit and function as a inductor of any value (within its range) to assist in identifying the optimal inductor size for the circuit.