Synchronous motor

A three-phase synchronous machine is a rotating electric machine. In principle, each three-phase synchronous machine can be operated as a motor and generator. Three-phase synchronous generators are used in the energy industry in a wide power range of the distribution of electricity and there are indispensable. Three-phase synchronous motors are versatile use as prime movers in the industry, such as drives for vehicles, boats and trains.

The synchronous machine gets its name because of the operating property that their runners exactly rotates synchronously with the rotating field defined by the grid frequency. This distinguishes synchronous machines clear of induction, early and late whose rotor the rotating field in the motor operation after and during generator operation. Another distinguishing feature is that, in contrast to induction motors for the operation of synchronous machines, an excitation field is required. Before a synchronous machine is connected to the network, they must be synchronized with the grid. In generator mode the machine is generally at a relatively constant speed. Contrast, synchronous motors must often be variable speed. In order to control a synchronous motor continuously in the speed, power electronics such as frequency used. A rotary encoder (line encoder, resolver) recognized in operating the rotor position change constantly. From this, the control electronics determine the actual speed. Under load, the rotor of the synchronous motor is running the rotating field at an angle, the rotor angle, afterwards. In generator mode the rotor angle is positive in the direction of rotation, so hurry before. Synchronous machines can absorb or emit reactive power. This can also be used for reactive power compensation the machine. The reactive power can be influenced by the excitation.

• 3.1 Economic Aspects
• 3.2 Advantages and disadvantages

• 4.1 generator operation
• 4.2 Motor operation
• 4.3 Operation with damper winding ( damper cage )
• 4.4 Phase-shift operation

History

The synchronous machine came from the mid-19th century as a single-phase generator for the supply of lighting systems used. Developed in 1887 by Friedrich August Haselwander and the American Charles Bradley Schenk independently the three-phase synchronous generator. In the development, the designs of the salient and Vollpolmaschine formed from. A co-founder of Brown, Boveri AG, Charles EL Brown, is considered the inventor of the roller runner, with grooves in the periphery of distributed field winding. The further development of the synchronous machine depended heavily along with the expansion of energy supply and the demand of more and more powerful generators. First, single-pole or salient- emerged, as these were likely to generate electricity with the slow running piston steam engines as the prime mover. When the steam turbines replaced the piston steam engines, the high-speed cylindrical smooth-core rotor were used. Regardless of synchronous machines have been used in the industry has always been when a constant input speed or phase shifter operation was needed.

Construction

Three-phase synchronous machines are running in different designs. They are manufactured as external or Innenpolmaschinen. Both types of machines have in common is that they have a rotor and a stator. In any case, an exciting means for the operation of the machines is required. Also, again there is a division into salient and Vollpolmaschinen.

Revolving field

The stator winding consists of three 120 ° / p (p = number of pole pairs ) displaced phase windings, which are denoted by U, V and W. They are connected in star or delta connection. About the stator winding electrical energy is fed into the network or from the grid in the motor operation in generator mode. The structure of the stator is similar to the three-phase asynchronous machine. The stand of the revolving field is also called armature and the stator winding accordingly armature winding.

The rotor of the revolving field can be implemented as salient or smooth-core rotor. Rotor, flywheel and rare inductor are also designations for both rotor configurations. The smooth-core rotor is also referred to as cylindrical rotor and full drum rotor. It is rotationally symmetrical and carries the excitation winding. The excitation winding is inserted into the grooves of the Vollpolläufers and fixed with splines. Salient pole pieces have pronounced and legs, which is why they have a large diameter. The excitation winding is wound on the leg of the armature.

There are several principles of arousal, for example, the static excitation. With this principle, the ends of the excitation winding through slip rings, which are located on the rotor shaft, led out. Via carbon brushes, the excitation voltage is applied to the excitation winding. Another principle is the brushless excitation on external pole synchronous generators and co-rotating diode rectifier (so-called RG- sets). This technique is however ( PSS sway control device, Eng. Power System Stabilizer) rarely used nowadays due to the increasing dynamic requirements in new power plants because RG- excitations react much slower than slip ring excitations. If it is a permanent-magnet machine, the rotor carrying permanent magnets for excitation. The permanent magnet excitation is gaining more and more importance.

Larger three-phase synchronous machines are equipped with a damper winding ( damper cage). It impacts on the operating behavior of synchronous machines. Versions will follow in the appropriate section. At Vollpolmaschinen amortisseur seated in the grooves of the exciter winding, or between these grooves in separate Dämpfernuten. In salient amortisseur sitting in separate Dämpfernuten of the pole pieces. The damper winding in Vollpolmaschinen is similar in principle to the construction of the squirrel-cage rotor of an induction machine. Synchronous machines but without a damper winding which, depending on the design, a certain internal damping, which also affects the property.

Vollpolmaschinen be operated at high speeds and therefore are well suited for use as turbine generators. The runners of these generators are called turbo runner. They are designed with a few pairs of poles and run at 50 Hz mains frequency with up to 3000 min -1. Due to the high speeds and the force acting on the rotor forces, these generators must be built slim and are not empty run because of the danger of over- speed. The size of Vollpolmaschinen is limited in diameter by the centrifugal limit and in length by the deflection limit.

Salient-pole are frequently used as low speed generators having large diameter and short length. They are designed with a large number of pole pairs and run at speeds 60-750 min -1.

Außenpolmaschine

In the stand Außenpolmaschine are pronounced pole shoes and legs, carrying the field winding. On the rotor, also called in the case of Außenpolmaschine anchor, is the three-stranded rotor winding. The ends of the rotor winding are brought out via slip rings. Carbon brushes take in generator mode, the power supplied from, or run the power required during motor operation to. This type is not recommended for machines with high power rating, as the currents increase as a function of performance. Associated with this are the increase in losses at the slip ring apparatus and the need to slip ring apparatus to execute larger, in order to carry the currents. For large Innenpolmaschinen services are used.

Interpretation of the windings

The windings of generators must be designed for the magnitude of the currents that occur when a short circuit. This also relates to the field winding, since high current peaks occur in their short circuit occurs. The highest short-circuit current occurs in a three- pin terminal short circuit when the engine is at the rated speed at idle and is energized at rated voltage. According to DIN VDE 0530, the short-circuit current may reach 21 times the rms value and 15 times the peak value of the rated current maximum.

Cooling

The stator windings and the exciter winding of synchronous machines heat up during operation by the currents occurring. The heat must be dissipated. In the lower power range that happens, for example, via cooling ribs of the stand and using fans. The air circulating in the housing and around the windings. For the circulation of a cooling fan is coupled to the rotor shaft. It is also a forced ventilation via an external fan. Large generators heat up very strong. The heat is carried away here through a water and hydrogen cooling. Here deionized water circulates through the designed as a hollow conductor stator winding. Instead of air is under pressurized hydrogen in the housing, which must be completely sealed in the case and withstand even an oxyhydrogen explosion. Due to the high thermal conductivity of hydrogen is thus achieved a significantly better cooling than with air. In earlier past prototypes were tested with superconducting field winding. Research is aimed, inter alia, increasing the air gap and density of the current pad. Using the technique should be possible to halve the active mass of the machine with the same performance.

Stand a salient of the French barrage Barrage de Marèges.

Slip rings and carbon brushes on the rotor of a synchronous generator in the power plant Amsteg.

For a revision of " solid " rotor of a turbine generator.

Slip ring apparatus of a hydro-generator; Excitation current of 500 A at 150 V

Application

Main applications of synchronous machines are the three-phase generators in power plants. Almost all conventional production electrical energy of synchronous generators. In thermal power plants Vollpolmaschinen come with capacities up to nearly 2000 MVA and output voltages from 21 kV to 27 kV are used. In Mülheim Siemens plant the world's largest generator of the Finnish Olkiluoto nuclear power plant was manufactured. It has a rated apparent power of 1992 MVA. These generators, with their rapidly rotating turbo runners are called in unity with the turbines turbine sets. The low-speed salient in hydroelectric plants are called hydroelectric power or hydro generators and provide a maximum of 25 kV stator voltage outputs up to 1000 MVA. Generators of smaller output of 10 kVA to 10 MVA come in small power plants and diesel generators for use and are usually also designed as salient. Synchronous generators for wind turbines are currently being manufactured with up to 6 MW. In addition, the use is in the treatment of local area networks. Thus, the synchronous generator is also used in the provision of electric energy for the operation of rail vehicles and marine propulsion and probably also in the future of road vehicles. A particular type of salient forms the claw pole and is primarily a motor vehicle generator (alternator ) are used.

Nacelle of Walchenseekraftwerk work; right the AEG- salient pole generators, left Francis turbines

Modern turbo-generator (yellow cylindrical unit in the middle); 800 MW; Nacelle Schwarze Pumpe power plant

Three-phase synchronous motor in the assembly

Three-phase synchronous motors high power serve as a drive for fans, pumps and compressors, and partly as conveyor drives (TGV, AGV ). With the ability to perform the speed control via frequency converter, the synchronous motor displaced large DC machines, but also gas turbines to drive turbo compressors. In the area of small and medium -performance engines come with permanent magnets for auxiliary and vehicle drives on the application. An application in the field of automation technology is the combination of two synchronous machines dar. This combination serves as a sensor and actuator for the transmission of angular positions of the rotor and is also known as resolver or synchro transformer. In addition to synchronous machines are used as a resolver, other types of machines.

Economic Aspects

The efficiency of a machine is determined among other things by the acquisition and operating costs as well as the efficiency. The efficiency of the synchronous machine ( 95 ... 99 %, depending on the size and the necessary excitation power ) is the basis of the synchronous voltage and current phases of the asynchronous machine is generally above. Large synchronous machines such as the turbo-generator are thus among the most effective energy converters. Due to the excitation device of the synchronous machine, the structure of the synchronous machine is more complex than in the asynchronous and thus more expensive. The cost of the electronic control system is similarly high as for the asynchronous machine. Permanent magnet synchronous machines achieve even higher efficiencies, as they must be supplied no excitation power. With the same performance and greater power density reduces the mass of the machinery or decrease the size. Generators of this type reached in wind power plants have an efficiency of over 98 %, which is higher than the efficiency of machines of the same size with electrical excitation. Permanent magnet excitation occurs only on machines of small to medium size used. The cost of the magnets fall in larger machines more and more significant, so that the economy towards machine is no longer with electromagnetic excitation. The complex assembly of the magnets also represents a major drawback

There are several manufacturers of electrical machinery and so only follows a selection of manufacturers with some of their products in the field of synchronous machines:

• ABB - Asea Brown Boveri - Synchronous Motors and Generators
• AEM - Anhaltisches Elektromotorenwerk Dessau - synchronous generators and motors
• General Electric - Synchronous Generators
• Leroy -Somer - Drives and Generators
• Lloyd Dynamo Werke - synchronous generators and motors, high voltage synchronous generators and motors, marine drives
• Loher - Permanent magnet synchronous motors and generators
• KSB AG / REEL - synchronous reluctance motors without permanent magnets
• Siemens - synchronous generators and motors, train motors, permanent-magnet servo motors
• VA Tech Elin EBG - synchronous generators and motors, synchronous traction motors
• UEM Group - synchronous generators, high voltage synchronous motors, marine drives

Under high voltage motors or high-voltage generators are understood machines with rated voltages above 1 kV. These names come about because in the VDE regulations already voltages greater than 1 kV are referred to as high voltage.

Pros and Cons

Advantages:

• Low moment of inertia
• Maintenance (if arousal without slip rings )
• Speed ​​regardless of load
• Relatively large air gap possible
• Reactive power control is possible when electrically energized (see Phase-shift operation )

Cons:

• Expensive material for permanent magnets and excitation power necessary, if not permanently excited
• Not self-starting ( without major attenuation)

Modes

Generator operation

Thus, the three-phase synchronous machine can operate as an electric generator, so as three-phase synchronous generator is a strain field in the rotor circuit is necessary ( internal pole ). That is, by a DC- rotor winding ( field winding ) or a permanent magnet to be produced, which induces a stator voltage in the strands of the stator winding, a magnetic field ( excitation field ). The phases of the stator winding are chained to the star. Obtained at the generator terminals ( ends of the strands U, V, W) is a three-phase AC voltage, three 120 ° phase-shifted AC voltages. The stator phase voltage (also called terminal voltage ) can be combined with knowledge of the synchronous reactance of the stator current and rotor voltage of the calculated as follows:

When using an excitation winding has to be supplied for generating the exciter field excitation power. There are various excitation systems, for example, the static excitation equipment or the brushless exciter device. To avoid damage to the generator in case of sudden load shedding, for larger machines own Entregungsschaltung is provided.

The number of pole pairs of the excitation winding is crucial for the rated speed of the generator and is defined as follows:

To run a two-pole () generator with 3000 min -1 and a four-pin () generator with 1500 min -1 at a frequency of the stator voltage of 50 Hz In addition, a coupled service to the generator shaft driven machine is necessary, such as an internal combustion engine or a turbine, which drives the rotor in rotation with the exciter field. That is, the working machine to the mechanical power to the generator, which converts the electric power generator. The supplied mechanical and not the output active power is obtained by calculation as follows:

• , The angular frequency (rotation speed in revolutions per second ) and supplied by the engine torque
• , With the linkage factor of the stator voltage, the stator current and the power factor

Are losses neglected, is valid. In the real generator occur but hysteresis and current heat losses and friction losses. Substituting the mechanical power supplied and the dissipated electric power in the ratio to obtain the efficiency of the machine, ie 100% is always less than 1.

Summary of action:

• Generator is located at the rated speed at idle
• The power circuit of the generator takes place if all the synchronization conditions are made
• On the engine mechanical power is supplied
• The generator would thereby accelerate, but is formed by the load on the electrical load in the network from a counter-torque that counteracts the torque of the machine
• It flows a three-phase alternating current ( stator current )
• The stator current causes a differential voltage across the synchronous reactance ( inductive reactance of the stator winding; ohmic resistance neglected)
• By the voltage drop to be a dependent of the stator current rotor angle ט is formed which is always positive in the direction of rotation in the generator mode
• As a result, the rotor voltage shifts for fixed line voltage (opposite the idle) with the angle of the pole wheel in the direction of rotation
• At constant moments of an equilibrium and a constant angular displacement train and the synchronous speed is unchanged; fluctuating loads on the network can disturb this balance

The stator voltage is load dependent. At constant excitation current and constant speed, various characteristic curves for capacitive, inductive and resistive loads arise. With a capacitive load results in an increase in voltage, resistive load gives a slightly drop and for inductive load, a sharp drop of the stator voltage. To maintain the constant stator voltage, which is the exciting current corresponding to the load to be controlled. The Regulierkennlinie illustrates how the excitation current according to the different loads to be controlled. Inductive load requires a high resistive load and a weak increase of the excitation current. To counteract the strong increase of the stator voltage for a capacitive load, the excitation current must be greatly reduced. For generators in large power plants, the excitation current is kept constant. Here, the voltage regulation is effected by means of step switch the downstream machine transformers.

Regulierkennlinie in island mode for constant terminal voltage

Synchronous generators can be damaged if any safety devices operate in asynchronous network circuit. A faulty synchronization of a generator has equalizing currents result, which in turn pull torques according to. Small false synchronisations and related oscillations (caused by the torques ) dampen the damper windings. Large false synchronisations cause damage to the generator, since the associated large torques acting on the machine and the machine foundation. If a generator in a power grid feed, so synchronization or even paralleling conditions must be met before a synchronization:

For the synchronization, different devices and circuits available ( light or dark operate, synchroscope ), but is now mostly relies on the automatic synchronization by digital control technology. The generator is switched to production of the synchronization conditions at idle to the network and can then be electrically charged, that deliver electric power.

Engine operating

For the engine operation and an excited rotor winding ( field winding ) or a permanent magnet is required as in the generator operation to generate an excitation field. It must also be supplied through the stator windings of electrical energy, so that the three-phase synchronous motor can produce a torque on the shaft. The absorbed power is calculated as follows:

The mechanical output corresponding to the received electric power loss minus the power component, which is made of copper and iron losses as well as frictional losses.

The ratio of mechanical output to electrical power input expresses the efficiency of the machine.

The simplified equivalent circuit of the synchronous machine can be found in the generator mode section. Article in three-phase machine, the driving principle is described by means of a rotary field, which is valid for synchronous, and asynchronous.

Summary of action:

• The synchronous machine is idle in the fixed grid
• It carried a load on the motor shaft by a work machine
• The engine would reduce its speed, but the engine now takes electrical power on and the stator current increases
• There now acts a motor torque, which counteracts the load torque
• The stator current causes a differential voltage across the synchronous reactance ( inductive reactance of the stator winding; ohmic resistance neglected)
• By the voltage drop to be a dependent of the stator current rotor angle ט formed which acts in motor operation opposite to the rotation direction
• As a result, the rotor voltage shifts for fixed line voltage (opposite the idle → idle pointer see picture generator operation ) with the angle of the pole wheel opposite to the rotation direction
• The motor is running at synchronous speed on; there will be no slippage as an induction motor

Synchronous motors with low attenuation do not start alone. The rotor of a synchronous motor usually has too much inertia to follow the rotating field from standstill. Therefore, the engine speed has to be unloaded is brought into the vicinity of the rotary field speed. Then, the excitation is switched on and the rotor of the motor is taken into the synchronous operation. Thereafter, the motor can be loaded. For the start, various methods are available:

• Pony motor: A angekuppelter starter motor (also starting motor) brings the speed of the synchronous motor in the vicinity of the rotating field speed. After synchronization of the starter motor is disengaged.
• Asynchronous start by additional damping cage in the rotor circuit: The damper cage of the synchronous motor can start using the principle of induction. Reaches the engine speed according to the energizing the rotating field speed, the damper cage loses its effect as a focal cage and the engine runs as a synchronous machine on. During startup, the exciter winding is usually shorted through a resistor to prevent the induction of high voltages and to increase the starting torque.
• Start frequency: The frequency of the supply voltage is continuously increased from zero to the rated frequency or rated the resulting rotating field speed. An outdated method to sets the frequency conversion by means upstream asynchronous, with frequency of the voltage supplied by the generator is increased over the supplied speed or his slip. Today, power electronic converters are used for frequency up. With this method, a load restart is possible.

Operation with damper winding ( damper cage )

The most important task of the damper winding of synchronous machines is to dampen mechanical torque oscillations. Torque oscillations occur through asynchronous, implement coupled to the synchronous machine machines with periodic torque (eg internal combustion engines as the prime mover or reciprocating compressors as a working machine) and load surges. In unbalanced operation ( unbalanced load ) and in extreme cases, in single-phase inverse phase sequence occurs, which is also attenuated. Would Undamped the inverse spin box to severe losses.

For generator operation is mainly the attenuation of the reverse field is important. Inverse fields induce a current in the damper winding, whose frequency is twice as high as the line frequency. The damper winding is performed in this case with a low resistance in order to keep the losses low.

During engine operation, especially pulsating torques are to be damped. When loaded with a constant load torque is under a constant load angle a balance between the rms current through the load and the torque supplied by the engine (see also spring model of the load angle of a synchronous machine ). Sudden increase of the load torque (load shock ) its rotation about the rotor displacement is delayed beyond due to the moment of inertia of the rotor. The load torque is now smaller than the motor torque and in turn caused by the moment of inertia acceleration to a too low load angle. This oscillation is repeated with ever-smaller amplitude until a balance is reached. By the relative movement between stator and rotor, a torque is generated according to the principle of the asynchronous machine, which counteracts the oscillations. Similarly also affect solid parts of the rotor as the rotor massive bales of Vollpolmaschine or the massive pole shoes of the salient. That is, a certain amount of attenuation can also occur without a damper winding. In addition to the damping of pulsating torques the damper winding can be used with squirrel cage also for self-starting according to the principle of the induction motor.

Phase-shift operation

As a phase shifter operating mode of a grid synchronized synchronous machine is called, is based solely on the reactive power from the grid or supplied to the grid. The synchronous machine is operated at idle and no distinction is made ​​between pure phase shifters and synchronous generators in the phase shifter operation. Pure phase shifters do not have a mechanical drive and are intended solely as a function of excitation, only the provision of inductive or capacitive reactive power. The shaft is not performed on these machines to the outside. They are primarily used to control in larger substations (network nodes ) application or installed in the vicinity of plants whose reactive power to compensate. They can be designed as salient or Vollpolmaschine. Synchronous generators in the phase shifter operation are located in power plants, which are operated intermittently and as needed as a phase shifter. For example, run synchronous machines in pumped storage power plants that are not in the pump or generator operating at idle. In gas turbine power plants, the generator in the phase-shifting operation by means of mechanical coupling of the gas turbine is separated by the active power losses caused by compression in the gas turbine to prevent. By raising or lowering of the excitation current ( over-excitation or underexcitation; see V curve ) the level of grid delivered or picked up from the net reactive power is affected. In overexcitation inductive reactive current is delivered (behavior as condenser) and under-excited synchronous machine takes the inductive reactive current on (behavior as coil). The inductive reactive power output corresponding to a recording of capacitive reactive power, and vice versa. The synchronous machine is thus used for reactive power compensation in electrical networks. In general, a synchronous machine in the phase shifter operation is overexcited operated since energy networks are usually more affected by inductive than capacitive loads. Energy networks take capacitive character from cable capacitance, when consumers are hardly on the net. This is for example the case at night, when large parts of the industrial plants are gone from the grid. The benefit of reactive power compensation is that the lines of the network, the reactive currents do not have to wear when they are already compensated in the vicinity of the plant.

V curve

If you operate a synchronous machine with constant mains voltage in the phase shifter operation, can record named after its waveform V curves. If you change at different constant active powers of the excitation current, and thus excite the synchronous machine above or below and carries you to the devoted stator currents on, we obtain the characteristic V curves. The loaded with active current synchronous machine may additionally assume that much of the over-or under arousal following reactive current to the rated current is reached.

Pictured five curves with the minima P0 can be seen up to P4 and arise in the various active to rated power ratios PS / PN. In the minima of the curves only real power is implemented. Left and right of additional reactive power. The curve with the minimum P0 is pure phase shifter operation. It is implemented no real power.

Upon reaching the stability limit, the machine falls in the engine operating out of step or goes through during generator operation.

Current locus

With the current locus of the operating behavior of synchronous machines can be represented. It can be statements about the mode, meet the exciting degree and the stability of operation of a synchronous machine. From the simplified equivalent circuit (RS = 0; see generator operation ) follows the formula for the stator voltage:

It can be derived, the stator current:

The locus of the hand of the stator voltage is in the real axis ( Re). The tip of the hand results in a circle having a radius of. This radius is due to variable, thus resulting in a concentric band of power loci for the synchronous machine. When there is a degree of excitation. , The resultant circle passes through the origin of the In -Re - coordinate system.

Characteristic points and areas:

• : Locus to a point
• : Under-excited operation
• And: overexcited operation
• : Phase-shift operation
• : Stable generator operation
• : Stable engine operation

Wave field in the air gap

In order to better understand the operating principle of a synchronous machine, you should consider the wave field in the air gap. The picture shows a two-pole synchronous machine ( 2 magnets, a north pole, a south pole ) with a three-phase Einlochwicklung (6 strands, 6 grooves ). The machine is idle.

The x-axis (0 ° to 360 ° ) passes in the air gap and represents the rotor circumference ( of here, so as not to have to commit to a certain radius, is given in degrees ). The y axis pointing upward, and outputs the value of the magnetic flux density in Tesla (T) as a function of and. The z-axis describes the rotation angle of 0 ° ( corresponding to image R1) to 180 ° (corresponding to the image R31 ), ie half a turn.

Clearly seen the effect of the two magnets, which generate a first approximately trapezoidal field of 10 ° to 170 ° or from 190 ° to 350 °. The mean width of the trapezoid ( about 140 ° ) corresponds approximately to the width of the magnet. This harness is independent of the angle of rotation ( z-axis) always available.

The oblique " grooves " are generated from the grooves: where the groove is even, the air gap is larger, and sets the magnetic flux is a greater resistance, the flux density is smaller at this point. Since the grooves rotate past the magnet, the groove becomes vertical in the diagram. If one follows a groove up, you will find that they also passes through on the x- axis exactly 180 °.

To generate a torque which must be in the grooves, which are just below the magnet, a current can flow. According to the principle of the Lorentz force

The torque is generated.

To produce the maximum torque (which the tipping moment is at the same time ), which is usually sinusoidal current in phase with the field surface wave must be.

Applicable DIN standards and VDE regulations DIN

• DIN VDE 0530 part 1 to 18 or corresponding parts of the DIN EN 60 034 or IEC 34
• DIN ISO 1940-1 - Balance quality requirements of rigid rotors; Determination of permissible residual unbalance
• DIN ISO 7919 - ... - Mechanical vibration of machines with non-reciprocating machines - Measurement and evaluation of wave oscillations
• DIN ISO 8821 - ... - Mechanical vibration agreement on the key - type in balancing of shafts and composite parts
• DIN ISO 10816 - ... - Mechanical vibration - Evaluation of machine vibration by measurements on non -rotating parts

For ex - proof areas are separate standards for:

• DIN VDE 0165 - Erection of electrical installations in hazardous areas
• DIN VDE 0166 - Erection of electrical installations in hazardous areas with potentially explosive substances
• DIN EN 50014 - Electrical apparatus for potentially explosive atmospheres; General provisions
• DIN EN 50016 - Electrical apparatus for potentially explosive atmospheres; Positive pressure enclosure " p"
• DIN EN 50019 - Electrical apparatus for potentially explosive atmospheres; Increased Safety " e"