Hydraulic System

I. BASIC PRINCIPLES OF HYDRAULIC SYSTEM.

In a hydraulic system fluid flow serves as a successor force. Mineral oil is a common type of fluid used.
The nature of the liquid:- Does not have a fixed shape, always adjust the shape they occupy.- Liquids can not be compressed.- Continuing pressure in all directions.

Hydraulics can be expressed as a means of transferring power by pushing a number of specific liquids. Component called a pressurized fluid flow generator pumps, and hydraulic pressure converter components into mechanical motion (straight / rotation) are called the working elements (cylinders / motors hidroulik).
The advantages of hydraulic systems:
- Flexibility in the placement of power transmission components.- Style is very small can be used to transport a large force.- Successor style (oil) also serves as a lubricant.- Expenses can be easily controlled using the pressure regulator valve (relief valve).- Can be operated at varying speeds.- Direction of operation can be reversed immediately.- It's safer if operating at overload.- Power can be stored in the accumulator.
The weakness of the hydraulic system:
Hydraulic systems require an environment that really clean. Its components are very sensitive to the damage caused by dust, corrosion and other impurities, and the heat affects the properties of hydraulic oils.


II. EQUATION / FORMULA BASIC.

Pressure is the force per unit cross-sectional area.In the equation expressed as:

P =, where P = Pressure / Pressure (Pascal).F = Force / force (Newton).A = Area / area (meter 2)
Capacity is the amount of flow per unit time.In the equation expressed as:

Q =, where Q = Capacity / Debit (m3/sec).V = Volume of Fluid (M3).t = Time (sec).
Or, Q = A x V, where A = Area (Meter 2).V = Fluid velocity (M / dt).
Boyle equation:
P1 x V1 = P2 x V2, where P = PressureV = Volume
Continuity equation:
Q1 = Q2 A1 x V1 = A2 x V2

Conversion unit:
- 1 Pascal = 1 Newton / meter2 (Pa = N/m2)- 1 bar = 105 Pa = 100 kPa= 14.7 psi (lbf / in2)= 1 Kgf / cm2- 1 m3/sec = 60 M3/menit- 1 M3/menit = 1000 LPM (liters / min).


Example:

Two related vessel, Style in vessel 1 (F1) = 1000 N.The diameter of the vessel 1 (d1) = 10 cm2Diameter of vessel 2 (d2) = 40 cm2Style on vessel 2 (F2) = ... ... ... ... .. ?


Completion:
- On Vessel 1:
Pressure 1 (P1) =

F1 = 200 N
A1 =; d1 = 10 cm 2 = 10 x 10-2 m2= 0.1 m
A1 = = 7.85 x 10-3 m2

P1 = = = 127.388 x 103 N/m2

= 1.27388 x 105 N/m2
= 1.27388 x 105 Pascal = 1.27388 Bar
- The vessel 2:
According to the law of Pascal 'Pressure in a closed vessel will be forwarded all directions with the same great'.- The pressure in vessel 1 (from calculation) = 1.27388 N/m2- In accordance with the laws of pascal the pressure on the vessel 2 will be equal to the pressure on the vessel 1.- Pressure in the vessel 2 (P2) = P1 = 1.27388 x 105 N/m2.
- Style on bejana2 (F2)
P2 =, then F2 = P2 x A2

P2 = 1.27388 x 105 N/m2
A2 = d2 = 40 cm = 40 x 10-2 m2= 0.4 m2
A2 = = 0.1256 m2

F2 = P2 x A2= 1.27388 x 105 N/m2 x 0.1256 m2= 16,000 N
So by using the principle of hydraulics can be concluded that with a small force F1 (1000N) to produce a much larger force F2 (16,000 N).

Valve Type

Below are brief explanations for the common types of valves used in today's industrial flow control industry. To view diagrams of each valve type, visit the Valve Photo Gallery.

MULTI-TURN VALVES OR LINEAR MOTION VALVES

The Gate Valve: The gate valve is a general service valve used primarily for on - off, non-throttling service. The valve is closed by a flat face, vertical disc, or gate that slides down through the valve to block the flow.

Directional Control Valves

Bang-bang is the term often used to describe basic directional-control valves. It refers to how the valves shift - from fully open to fully closed. This usually occurs in an instant, causing fluid to rapidly accelerate and decelerate. Under certain conditions, this can cause fluid hammer, which sounds like a hammer striking the hydraulic system from inside. Hence, shifting the valve from one position to another can produce a bang-bang sound.

Fig. 1. Basic check valve allows fluid to flow in one direction, in this case from bottom to top. Shown are ISO symbol and cross-sectional photo of spring-loaded check valve. The spring keeps fluid from flowing unless downstream pressure acting on the poppet overcomes spring force. 

A less informal term to describe these components is discrete valves. This term refers to how the valves operate: they shift from one discrete position to another, such as extend, retract, and neutral. Proportional valves, on the other hand, control direction and speed. In addition to shifting into discrete positions, they can shift into intermediate positions to control actuator direction, speed, acceleration, and deceleration.
Even more basic than the discrete directional-control valve is the digital valve. As in digital electronics, digital valves operate either on or off. Whereas discrete valves generally use a spool to achieve two, three, or more positions, discrete valves use a plunger, poppet, or ball that seals against a seat. The advantage to this type of operation is that it provides a positive seal to prevent cross-port leakage.
Perhaps the simplest of all directional-control valves is the check valve, a specific type of digital valve. Basic check valves allow fluid to flow in one direction, but prevent fluid from flowing in the opposite direction. As with all fluid power components, directional-control valves can be represented by standard symbols published in ISO 1219. Figure 1 shows a cross-section of a spring-loaded check valve and its ISO 1219 representation.

Ports and positions

Selenoid Valve Hystory

Solenoid valves technology history

Solenoid valves have made remarkable progress over the last three decades. Manual shutoff has given way to automated shutdown systems. In-line mounted valves have lost their popularity to pad mounted valves. And, specialized actuator designs have moved to standardized designs in the presence of the European NAMUR standard. These are only a few of the many changes that have occurred to the solenoid valve, the workhorse of the chemical processor's valve system. The solenoid valve has made tremendous leaps in the chemical processing industry. Yet, at the same time, market conditions can dictate the need to continue enhancing solenoid valve technology.

Solenoid Valves Evolution

During the 1970s, the chemical industry primarily utilized linear control valves that employed a rising stem. Once automated, these valves required pipe-mounted solenoid valves. Solenoid valve designed initially for linear control valves were, at this point, playing double-duty because they were being used for quarter-turn ball valves as well.
The quarter-turn ball valve, with its suitability for automated packages, began to gain popularity in the 1980s. In time, actuator manufacturers began to develop their own flat plates. They embedded these flat plates into the actuator by using an interface that had a direct-coupled solenoid valve. This flat interface found its way in time to close coupling against a flat-style valve. Eventually, spool valves replaced the flat-style valve for this application.
However, because standardization was not widespread at the time, each actuator manufacturer tended to have a unique interface configuration. Consequently, solenoid valve manufacturers needed to design five to six different styles of valves to fit onto these various actuators. It was not until the 1990s that the valve industry instituted its own standardization for an interface with the solenoid valve.

Hydraulic System

I. BASIC PRINCIPLES OF HYDRAULIC SYSTEM.
In a hydraulic system fluid flow serves as a successor force. Mineral oil is a common type of fluid used.
The nature of the liquid:- Does not have a fixed shape, always adjust the shape they occupy.- Liquids can not be compressed.- Continuing pressure in all directions.

Hydraulics can be expressed as a means of transferring power by pushing a number of specific liquids. Component called a pressurized fluid flow generator pumps, and hydraulic pressure converter components into mechanical motion (straight / rotation) are called the working elements (cylinders / motors hidroulik).
The advantages of hydraulic systems:
- Flexibility in the placement of power transmission components.- Style is very small can be used to transport a large force.- Successor style (oil) also serves as a lubricant.- Expenses can be easily controlled using the pressure regulator valve (relief valve).- Can be operated at varying speeds.- Direction of operation can be reversed immediately.- It's safer if operating at overload.- Power can be stored in the accumulator.
The weakness of the hydraulic system:
Hydraulic systems require an environment that really clean. Its components are very sensitive to the damage caused by dust, corrosion and other impurities, and the heat affects the properties of hydraulic oils.


II. EQUATION / FORMULA BASIC.

Pressure is the force per unit cross-sectional area.In the equation expressed as:

P =, where P = Pressure / Pressure (Pascal).F = Force / force (Newton).A = Area / area (meter 2)
Capacity is the amount of flow per unit time.In the equation expressed as:

Q =, where Q = Capacity / Debit (m3/sec).V = Volume of Fluid (M3).t = Time (sec).
Or, Q = A x V, where A = Area (Meter 2).V = Fluid velocity (M / dt).
Boyle equation:
P1 x V1 = P2 x V2, where P = PressureV = Volume
Continuity equation:
Q1 = Q2 A1 x V1 = A2 x V2

Vector Group Transformer

Transformer nameplates carry a vector group reference such at Yy0, Yd1, Dyn11 etc.  This relatively simple nomenclature provides important information about the way in which three phase windings are connected and any phase displacement that occurs.
Winding Connections
HV windings are designated:   Y, D or Z (upper case)
LV windings are designated:    y, d or z (lower case)
Where:
Y or y indicates a star connection
D or d indicates a delta connection
Z or z indicates a zigzag connection
N or n indicates that the neutral point is brought out
Phase Displacement
The digits ( 0, 1, 11 etc) relate to the phase displacement between the HV and LV windings using a clock face notation.  The phasor representing the HV winding is taken as reference and set at 12 o'clock.  It then follows that:
Digit 0 means that the LV phasor is in phase with the HV phasor
Digit 1 that it lags by 30 degrees
Digit 11 that it leads by 30 degrees
etc
All references are taken from phase-to-neutral and assume a counter-clockwise phase rotation.  The neutral point may be real (as in a star connection) or imaginary (as in a delta connection)
When transformers are operated in parallel it is important that any phase shift is the same through each.  Paralleling typically occurs when transformers are located at one site and connected to a common busbar (banked) or located at different sites with the secondary terminals connected via distribution or transmission circuits consisting of cables and overhead lines 
Basic Theory
An ac voltage applied to a coil will induce a voltage in a second coil where the two are linked by a magnetic path.  The phase relationship of the two voltages depends upon which way round the coils are connected.  The voltages will either be in-phase or displaced by 180 deg as below:

 in phase

180 deg displacement

Transformer Oil Test

Insulating oil of transformers and current transformers fulfills the purpose of insulating as well as cooling. On a regular schedule, it must be subject to an oil test to determine its breakdown voltage.

 

The oil test is essential and in most countries even mandatory, since the dielectric oil deteriorates in its isolating and cooling qualities due to ageing and pollution by dust particles or humidity, potentially endangering operational facilities and staff.

 Breakdown during an oil test

International standards define the test sequence and procedure of such an oil test.

Transformer in Voltage and Current

Current or voltage instrument transformers are necessary for isolating the protection, control and measurement equipment from the high voltages of a power system, and for supplying the equipment with the appropriate values of current and voltage - generally these are 1A or 5Α for the current coils, and 120 V for the voltage coils.

The behavior of current and voltage transformers during and after the occurrence of a fault is critical in electrical protection since errors in the signal from a transformer can cause maloperation of the relays.

In addition, factors such as the transient period and saturation must be taken into account when selecting the appropriate transformer.

When only voltage or current magnitudes are required to operate a relay then the relative direction of the current flow in the transformer windings is not important. However, the polarity must be kept in mind when the relays compare the sum or difference of the currents.

1- Voltage transformers:

          With voltage transformers (VTs) it is essential that the voltage from the secondary winding should be as near as possible proportional to the primary voltage.

          In order to achieve this, VTs are designed in such a way that the voltage drops in the windings are small and the flux density in the core is well below the saturation value so that the magnetization current is small; in this way magnetization impedance is obtained which is practically constant over the required voltage range. The secondary voltage of a VT is usually 110 or 120 V with corresponding line-to-neutral values. The majority of protection relays have nominal voltages of 110 or 63.5 V, depending on whether their connection is line-to-line or line-to-neutral.

Voltage transformer equivalent circuits

Vector diagram for voltage transformer

Cascade Control in The Loop

Cascade Control uses the output of the primary controller to manipulate the setpoint of the secondary controller as if it were the final control element.
Reasons for cascade control:

• Allow faster secondary controller to handle disturbances in the secondary loop.
• Allow secondary controller to handle non-linear valve and other final control element problems.
• Allow operator to directly control secondary loop during certain modes of operation (such as startup).

Requirements for cascade control:

• Secondary loop process dynamics must be at least four times as fast as primary loop process dynamics.
• Secondary loop must have influence over the primary loop.
• Secondary loop must be measured and controllable.

Reasons not to use cascade:

• Cost of measurement of secondary variable (assuming it is not measured for other reasons).
• Additional complexity.

Examples of cascade control:

Control of heat exchanger outlet temperature using steam flow as secondary loop.

Supervisory Control And Data Aquisition

Following we describe the SCADA systems in terms of their architecture, their interface to the process hardware, the functionality and the application development facilities they provide.

SCADA systems have made substantial progress over the recent years in terms of functionality, scalability, performance and openness such that they are an alternative to in house development even for very demanding and complex control systems.

What does SCADA mean?
SCADA stands for Supervisory Control And Data Acquisition. As the name indicates, it is not a full control system, but rather focuses on the supervisory level. As such, it is a purely software package that is positioned on top of hardware to which it is interfaced, in general via Programmable Logic Controllers (PLC's), or other commercial hardware modules.

SCADA systems are used not only in industrial processes: e.g. steel making, power generation (conventional and nuclear) and distribution, chemistry, but also in some experimental facilities such as nuclear fusion. The size of such plants range from a few 1000 to several 10 thousands input/output (I/O) channels. However, SCADA systems evolve rapidly and are now penetrating the market of plants with a number of I/O channels of several 100 thousands I/O's

SCADA systems used to run on DOS, VMS and UNIX; in recent years all SCADA vendors have moved to NT, Windows XP, Windows Server 2003 and some also to Linux.

1. Architecture

This section describes the common features of the SCADA products.

Hardware Architecture
One distinguishes two basic layers in a SCADA system: the "client layer" which caters for the man machine interaction and the "data server layer" which handles most of the process data control activities. The data servers communicate with devices in the field through process controllers. Process controllers, e.g. PLC's, are connected to the data servers either directly or via networks or fieldbuses that are proprietary (e.g. Siemens H1), or non-proprietary (e.g. Profibus). Data servers are connected to each other and to client stations via an Ethernet LAN.

SCADA Hardware Architecture

What is the difference? PLC and DCS

You must automate a process, but you can't decide between a DCS and a PLC. Are these systems really all that different? The answers depend on a slew of other questions.


Turn the clock back 10-15 years: The programmable logic controller (PLC) is king of machine control while the distributed control system (DCS) dominates process control. If you manufacture plastic widgets, you speak PLC. If you produce chemicals, you speak DCS.

Today, the two technologies share kingdoms as the functional lines between them continue to blur. We now use each where the other used to rule. However, PLCs still dominate high-speed machine control, and DCSs prevail in complex continuous processes.

The early DCS looked dramatically different from the early PLC. Initially, the DCS performed the control functions of the analog panel instruments it replaced, and its interface mimicked their panel displays. DCSs then gained sequence logic capabilities to control batch processes as well as continuous ones. DCSs performed hundreds of analog measurements and controlled dozens of analog outputs, using multi-variable Proportional Integral Derivative (PID) control. With the same 8-bit microprocessor technology that gave rise to the DCS, PLCs began replacing conventional relay/solid-state logic in machine control. PLCs dealt with contact input/output (I/O) and started/stopped motors by performing Boolean logic calculations.

pH Control for Control Valve Error

Up until now, we have considered that the control valve was ideal - i.e. the valve provides whatever reagent flow rate we desire (with saturation limits). In reality, things aren't that simple, with most valves displaying backlash characteristics. You should recall the discussion of backlash in the ball and plate control example.
For now, we will assume that the backlash error is 2% of the maximum flow rate allowed by the valve. Often, the valve errors can be as large as 5% or 10%. The block diagram of this new system is shown below:

With the influent flow variations discussed in the last example, there are now two sources of error in the system. In order to understand them better, we will examine them separately. Since the last example showed the effect of flow variations alone, we will now look at the effect of the valve errors alone.
The nature of the valve hysteresis is such that a simple exponential step response will be largely unaffected. Thus, to highlight the effect of the hysteresis, we will allow extremely small influent flow variations. The influent flow q(t) is then the nominal 10 L/min plus a small sinusoidal variation of amplitude 0.0003 L/min and period 10000 s.

Multiple Tanks for pH Control

To overcome the flow variations and the valve hysteresis problems, we use a 3 tank system where the tanks increase in volume. This setup is shown in the diagram below.

The influent flows into the first tank, which has a large valve to neutralise most of the influent base. The set-point for this control system is set to a pH of 9.6, since the purpose of the 3 tank system is to attack the problem in steps.
The effluent from the first tank flows directly into the second tank, which is 20 times larger. The second tank uses a valve that is 20 times smaller than that used by the first tank. The set-point for this control system is set to pH 8.3.
The effluent from the second  tank flows directly into the third  tank, which is 20 times larger again. The third tank uses a valve that is 20 times smaller than that used by the second tank (and thus 400 times smaller than the first tank). The set-point for this final tank is a pH of 7.

pH Control for Flow Variations

If the system's influent flow is from some sort of industrial runoff, then it is highly likely that the flow rate will vary, since the runoff will not be at a constant rate. The variation in influent flow rate presents itself as an input disturbance in the plant model.

where q(t) is the flow rate signal. In this example, we model the fluctuations as a constant flow plus some randomly varying noise. In particular, we set the average flow to the level used in the last example (10 L/min), and the random variations range uniformly between -1 L/min and 1L/min.
We will use the same controller as in the last example, which is based on the nominal flow rate of 10 L/min.  However, we should note that allowing the q(t) input to vary with time makes the system more non-linear than before.

Space Vector Modulation in PWM

Space vector modulation is a means of generating a three phase variable voltage, variable frequency PWM output voltage.

The inverter comprises six solid state switches, two for each phase with one switch on each phase connecting to the positive rail and one switch connecting to the negative rail. By a combination of switching states of these output switches, we can create a sinusoidal output current.
In effect, there are eight states that define six output vectors and two NULL vectors.
S0 = 000 : NULL
S1 = 100 : Vector 1
S2 = 110 : Vector 2
S3 = 010 : Vector 3
S4 = 011 : Vector 4
S5 = 001 : Vector 5
S6 = 101 : Vector 6
S7 = 111 : NULL

System Model of pH Control

From elementary mass balance considerations, it can be shown that an appropriate state space model for the strong acid-strong base system is

where

co(t) :		excess hydrogen ion concentration in the effluent stream (mol/L)
cu(t) :		excess hydrogen ion concentration of the reagent (mol/L)
ci(t) :		excess hydrogen ion concentration in the influent stream (mol/L)
u(t) :		flow rate of the reagent (L/s)
q(t) :		flow rate of the influent stream (L/s)
V :		volume of the tank (L)

Normally, the reagent concentration is constant, and we control the effluent pH by varying the reagent flow. Note that the concentrations are excess concentrations, meaning that they measure the concentration of hydrogen ions in excess to that found in water. We can convert an excess concentration C to pH using the following formula.

pH Control System

pH control is a common issue in many industrial processes. The basic idea to control the pH variations in some liquid flow, usually making the pH as close to 7 as possible. This influent liquid flows into a tank, where it is mixed with an amount of a concentrated reagent to alter its pH. If the effluent is acidic with a pH of 4, the reagent would be basic with a pH larger than 10. The reagent is more concentrated than the effluent, since it is desirable to as little volume to the effluent as possible.
The pH is controlled in a tank - the effluent flows into the top of the tank, and the reagent is also added to the top of the tank. The tank is well-stirred so that the pH is uniform throughout the tank. The effluent is pumped out the bottom of the tank, as shown in the figure below.

ASCII Code

American Standard Code for Information Interchange. This is the basic clear-text Latin characters. There are 128 standard ASCII codes, each of which can be represented by a 7 digit binary number: 0000000 through 1111111.
Extended ASCII adds an additional 128 characters that vary between computers, programs and fonts.

7 Bit ASCII Codes

Induction Motors Soft Starter

Soft Starters   

A soft starter is another form of reduced voltage starter for A.C. induction motors. The soft starter is similar to a primary resistance or primary reactance starter in that it is in series with the supply to the motor. (Three wire or standard connection) The current into the starter equals the current out. The soft starter employs solid state devices to control the current flow and therefore the voltage applied to the motor. In theory, soft starters can be connected in series with the line voltage applied to the motor, or can be connected inside the delta loop of a delta connected motor, controlling the voltage applied to each winding. (Six wire or Inside Delta connection)

 

 

Voltage Control

Voltage control is achieved by means of solid state A.C. switches in series with one or more phases. These switches comprise either: 

        1 x Triac per phase

1 x SCR and 1 x Diode reverse parallel connected per phase.

       2 x SCRs reverse parallel connected per phase

The Theory of Variable Speed Drive

Methods of speed control.
The speed of a driven load often needs to run at a speed that varies according to the operation it is performing. The speed in some cases such as pumping may need to change dynamically to suit the conditions, and in other cases may only change with a change in process. Electric motors and coupling combinations used for altering the speed will behave as either a "Speed Source" or a "Torque Source". The "Speed Source" is one where the driven load is driven at a constant speed independent of load torque. A "Torque Source" is one where the driven load is driven by a constant torque, and the speed alters to the point where the torque of the driven load equals the torque delivered by the motor. Closed loop controllers employ a feedback loop to convert a "Torque Source" into a "Speed Source" controller.

Mechanical.
There are a number of methods of mechanically varying the speed of the driven load when the driving motor is operating at a constant speed. These are typically:

Belt Drive

Chain Drive

Gear Box

Idler wheel drive

All of these methods exhibit similar characteristics whereby the motor operates at a constant speed and the coupling ratio alters the speed of the driven load. Increasing the torque load on the output of the coupling device, will increase the torque load on the motor. As the motor is operating at full voltage and rated frequency, it is capable of delivering rated output power.
There is some power loss in the coupling device resulting in a reduction of overall efficiency. The maximum achievable efficiency is dependant on the design of the coupling device and sometimes the way it is set up. (e.g. belt tension, no of belts, type of belts etc.)
Most mechanical coupling devices are constant ratio devices and consequently the load can only be run at one or more predetermined speeds. There are some mechanical methods that do allow for a dynamic speed variation but these are less common and more expensive.
Mechanical speed change methods obey the 'Constant Power Law' where the total power input is equal to the total power output. As the motor is capable of delivering rated power output, the output power capacity of the combination of motor and coupling device (provided the coupling device is appropriately rated) is the rated motor output power minus the loss power of the coupling device.
Torque 'T' is a Constant 'K' times the Power 'P' divided by the speed 'N'.

T = K x P / N

Therefore for an ideal lossless system, the torque at the output of the coupling device is increased by the coupling ration for a reduced speed, or reduced by the coupling ratio for an increased speed.

Pneumatic Transmitter Working Principle In The Measurement of Level in Tank Open

Pneumatic transmitter is a device for measuring liquid level in the tank, where to find out how much height the fluid according to predetermined based on the needs. Pneumatic transmitter is working to change the process signal into the instrument signal and sends these signals to a receiver such as recorder (recorder), the pointer. Process measurement using pneumatic transmitter which the transmitter used is the slider (Displacer). The transmitter consists of a tentacle (detector) and the sender, where the transmitter is to measure the amount of acceptable level detector in the form and then process the signal on the sender of this pneumatic transmitter signal change process into the instrument signal and sends it to the controller. Signals generated by the pneumatic transmitter is 0.2 to 1.0 kg/cm2. if the state of 0%, then the pressure of the transmitter shows the pressure of 0.2 kg/cm2. If at state 100%, then the pressure of the transmitter shows the pressure of 1.0 kg/cm2.

Dynamic Pressure Callibration

High-frequency pressure sensors capable of measuring shock waves, blast, rocket combustion instability, and ballistics were initially developed by researchers for laboratory use. Here’s an overview of some of the sensor types, and associated calibration equipment, available on the commercial market.

Jim Lally and Dan Cummiskey,

PCB Piezotronics Inc.

In the 1950s and 1960s, with the advent of the aerospace era and weapons development came a requirement for high-frequency pressure sensors capable of measuring shock waves, blast, rocket combustion instability, and ballistics. Piezoelectric sensors available at the time had limited frequency response and were used mainly for acoustic and engine combustion applications. It was during this period that Walter Kistler, working closely with Abe Hertzberg at the former Cornell Aeronautical Labs in Buffalo, NY, developed miniature high-frequency acceleration-compensated quartz pressure sensors with microsecond response time. This research spearheaded the development of shock tube technology crucial to studying the sort of aerodynamic shock waves that spacecraft can encounter during reentry. Other research facilities devised special sensors tailored to their specific applications. At Aberdeen Proving Ground, Ben Granath designed blast pressure sensors for weapons development and a unique, tourmaline, nonresonant pressure bar for reflected shock wave measurements. A young engineer at Sandia National Laboratories, Pat Walter, provided invaluable feedback on these early sensor designs.

Renewable of Power Generation

Renewable power generation is one of the most important subjects in today's electricity production industy and in the future will dominate the agenda to remove power generation from the use of fossil fuels
Of all the energy currently consumed in Canada, about 3,700 PJ (46%) is used to generate electricity. Canada has approximately 112 GW of installed electricity generation capacity, and produces approximately 561,805 GWh of electricity annually11 , resulting in a $27 B/yr business12 . Most electricity generation, transmission and distribution have traditionally been handled by vertically integrated provincial monopolies. This resulted in the construction of large-scale centralized power generation facilities and massive transmission systems owned by the same generator. The market is currently evolving under new deregulation guidelines.

Renewable Electricity Energy

Renewable Electricity Renewable electricity (RE) policy is an important subset of industrial and energy policy, and thus needs to be aligned with the energy policy priorities of sustainability, competitiveness, and security. Our common and only long-term natural advantage in the energy sector stems from renewable electricity resources such as wind, biomass, and ocean energy.
Climate change mitigation and security of supply have become the focus of many recent national electricity policies. Renewable energy resources can play an important part in addressing both of these concerns.

Against a current background of high and volatile fossil fuel prices and strong demand growth for electricity, this page focuses on one aspect of sustainable energy, namely renewable electricity.
Consumers demand secure, dependable and competitively priced electricity and producers must be responsive to these market requirements.
The combination of increased demand for renewable electricity and security of supply is a very powerful driver of major power sector change worldwide. Currently, for example, about 50% energy demand is met with imported fuels and there are projections that this could increase to 70% in the coming decades. Economic development and increasing use of electricity-consuming devices will increase future demand for electricity.
Alongside electricity demand and security of supply issues, climate change also poses a global threat. Substantial and fairly rapid decarbonisation of electricity generation and many other sectors will have to take place if the world is to have any chance of staying within the 2 degree C goal for limiting the effects of global warming.

Renewable Energy Source

Renewable Energy is electricity that is produced from renewable sources of energy lsuch as: wind power, solar power, geothermal energy, and hydroelectric energy. Renewable energy sources are readily replenished by nature and are a cleaner, non-carbon polluting source of energy like oil, coal and natural gas. Renewable Energy sources are often referred to as emerging energy technologies.

In recent years, the cost of emerging energy technologies have decreased to the extent that renewable energy technologies are competing with traditional sources of energy. Investigate your options. Information is available from a range of sources, including renewable energy associations, consultants and vendors.
Renewable energy electricity production is expected to expand significantly over the coming years in the developed world. This represents an opportunity for developed countries (large electricity consumers) to develop and commercialize new and competitive technologies to the traditional "fossil fuel" based technologies and thereby manufacture products and offer services in support of a growing industry.

Protection of Arc Flash ( Electrical Safety Resource Information )

Arc flash protection first became an issue of serious study in the early 1980s when in the IEEE Transactions on Industry Applications there appeared an article by Ralph Lee titled: “The Other Electrical Hazard: Electric Arc Blast Burns.” These early studies convinced several companies, particularly those in the petrochemical industry, that too many workers were suffering burn injuries from electrical safety incidents. A consequence was that several companies took steps to establish the first set of known practices designed to better protect employees and electrical personnel who were working on energized electrical equipment.

While petrochemical companies were some of the first to recognize the need for electrical safety defence, because the dangers apply to all electrical installations. Although the amount of energy released in an electrical safety explosion may be greater for higher voltage installations found in some petrochemical and other industrial plants, the sheer volume of low voltage equipment in commercial and industrial facilities means that installations like these account for the greatest number of electrical safety incidents.