Some knowledge of the earth

When required by the design without,at the top of the grounding device buried depth of not less than 0.6 meters.Round steel,Angle steel,and copper tube ground level should be buried,vertical spacing not permanent magnet generators for sale less than 5 meters,grounding device should concentrate,lead the grounding device in parallel with main welding into a loop - grounding network.Grounding network has reliable grounding,grounding resistance is small,the characteristics of suitable for the need of a large number of electrical equipment grounding,more used to power distribution,large workshop and other places,pressure is the most important function generator stator of grounding network,namely to equal to the voltage of each node on the net.


To safe operation of the equipment and personal safety play an important role,covers an area of big but potential distribution uniformity,fever when the ground current is big is small,less electrolyte corrosion.For earth cover an area of an electric motors 12 volt area small but potential distribution and corrosion.From artificial grounding device of horizontal distance of not less than 3 meters,the depth of the grounding line is not less than 1 meter.For more than ten years of practice has proved that not so much important,grounding resistance than grounding device structure is more reasonable and important.Now city,in a building with many different properties of electrical equipment,need wholesalemotor.blogspot.com a variety of grounding device,such as lightning protection grounding,electrical safety,communication power supply working grounding,communications and computer systems (also called dc grounding,grounding in digital logic system called logic),etc.,so many system which adopts heavy good grounding? Now explain one by one as follows: according to the practice proved that the common grounding is most widely used method.

The working principle of the permanent magnet synchronous motor

The working principle of the permanent magnet synchronous motor measurement device problem complement advantages and weaknesses: measuring equipment PM synchronous motor synchronous generator in order to realize the transformation of energy,need to have a dc magnetic field.And the direct current magnetic field,Known as the generator excitation current.According to the method of field current supply,which obtained from other 220v ac electric motorssource excitation current of the generator,called separately excited generator,excitation power from the generator itself,it is called a self-excited generators.A,power generation Machine for several kinds of mode 1,dc generator excitation current excitation power supply: this way of excitation generator has a dedicated dc generator,the dedicated dc generator,called dc exciter,generally with generator exciter Axis,generator exciting winding through perfectly on the large axial slip ring and fixed brush obtained from dc exciter current.This way of field independent excitation current,more reliable and decrease for electricity consumption,etc,is in the past few decades Main motor excitation way and has a mature operating experience.Defect is excitation regulating speed slower,maintenance workload is big,it is rarely used in more than 10 mw units.

2,ac exciter power supply mode of excitation,modern large capacity power generation Provide field current machine some use ac exciter.Ac exciter is installed on the generator shaft,its output of alternating current flows through the rectifier supply generator rotor excitation,at this point,his way of excitation of generator excitation way,and as a result of the static Check of the rectifying device,so it is also called separately excited static excitation,exchange vice exciter

excitation current.Deputy exciter communication can be permanent magnetic measuring device machine or alternator with self-excitation constant pressure device.In order to improve the excitation

regulating speed,ac excitation Magnetic machine usually USES the 100-200 hz frequency generator,vice exciter and communication,the use of the 400-500 hz frequency generator.This kind of generator and three-phase ac dc excitation winding winding around the stator slot,rotor teeth and slots not only round Group,like a gear,therefore,it has no brush and slip ring contact parts such as rotation,has

reliable operation,simple structure,convenient manufacturing process.The disadvantage is induction motor price that the noise is bigger,ac voltage harmonic component is bigger also.

3,without exciter excitation Magnetic way: in the way of excitation is not set up special exciter,and obtained from the generator itself excitation power supply,the rectifier supply again after excitation generator itself,according to static excitation self-excitation type.Static excitation self-excitation type can be divided into the shunt and the compound of two Kind of way.Since the shunt way it through joint in the export of generator excitation current of rectifier transformer,the rectifier supply generator excitation,after this way of excitation has simple knot,equipment,less investment and less maintenance workload,etc.Since after Besides no rectification transformer excitation mode,also has series high- power current transformer in generator stator loop.This is used in the case of short circuit of

transformer,provide generator excitation current,to make up for the rectifier transformer output is not The foot.This way of excitation has two kinds of 220v ac electric motors excitation source,through the voltage rectifier transformer power supply and current source through series transformer.

Only a winding motor,rotor cage type

When a single-phase sinusoidal current in the stator winding,the motor can produce an alternating magnetic field,the magnetic field strength and direction interplanting sine law of change at any time,but is fixed on the spatial orientation,say again so the magnetic field is alternation pulse magnetic field.This alternation pulse magnetic field can be decomposed into two at the same speed and direction of rotation are instead of a rotating magnetic field,when the rotor static,the two rotating magnetic field generated in the rotor torque of two equal and opposite,making synthetic torque is zero,so the motor can't rotate.When we use the motor rotates in the direction of a force (clockwise),then the rotation of the rotor and clockwise direction magnetic field between the cutting lines of magnetic force movement decreases;The rotation of the rotor and counterclockwise direction magnetic field cutting lines of magnetic force between the movement.This balance is broken,the total electromagnetic torque generated by the rotor will no longer be zero,rotor spun along the driving direction.

To make single-phase electric function automatically spin,we can add a starter in the stator winding,starting with the main windings in space by 90 degrees,starting winding to generator rotor and stator concatenate a suitable capacitance,makes differ with approximation in the phase of the primary winding current 90 degrees,the so-called split-phase principle.These two differ 90 degrees of electricity flow in time into the two differ 90 degrees of winding on the space,will be produced in the space (two-phase) rotating magnetic field,under the effect of the rotating magnetic field,the rotor can be automatic starting,after starting,to speed up to a certain,with the aid of an installed on the rotor of the centrifugal switch or other automatic control device will start winding broken,only main winding work in normal working conditions.Therefore,starting winding can make short work.But there are a lot of time,starting winding is not broken,we call this kind of motor capacitor,single-phase motor to change this kind of motor,can be achieved by changing the position of the capacitor is concatenated.In single phase motor,the rotating magnetic field generated another method called shield electrode method,also known as single phase mask pole type motor.This made salient pole motor stator,which has two kinds of the poles and quadrupole.Each pole in a third - quarter pole face open place with full of small tank,the pole is divided into two parts,on the small part of the suit on a short circuit copper ring,like pole to cover up this part,so called cover pole type motor.

Single-phase winding set in the entire history of the magnetic poles,each pole of the coil is connected in series,the connection must make its polarity,in turn,according to the N,S,N,S arrangement.When the stator winding current,the magnetic pole of the main magnetic flux,according to lenz's law,which through the short circuit copper ring main magnetic flux on the copper ring on a phase lag is only one winding

single-phase ac motor,the rotor's cage.When a single-phase sinusoidal current in the stator winding,the motor can produce an alternating magnetic field,the magnetic field strength and direction interplanting sine law of change at any time,but is fixed on the spatial orientation,say again so the magnetic field is alternation pulse magnetic field.This alternation pulse magnetic field can be

decomposed into two at the same speed and direction of rotation are instead of a rotating magnetic

field,when the rotor static,the two rotating magnetic field generated in the rotor torque of two

equal and opposite,making synthetic torque is zero,so the motor can't rotate.

When we use the motor rotates in the direction of a force (clockwise),then the rotation of the rotor and clockwise direction magnetic field between the cutting lines of magnetic force movement decreases;The rotation of the rotor and counterclockwise direction magnetic field cutting lines of magnetic force between the movement.This balance is broken,the total electromagnetic torque generated by the rotor will no longer be zero,rotor spun along the driving direction.To make single-phase electric function automatically spin,we can decide on Adding a starting winding son,starting with the main windings in space by 90 degrees,starting winding to concatenate a suitable capacitance,makes differ with on the phase of the primary winding current approximate 90 degrees,the so-called split-phase principle.These two differ 90 degrees of electricity flow in time into the two differ pumps 90 degrees of winding on the space,will be produced in the space (two-phase) rotating magnetic field,under the effect of the rotating magnetic field,the rotor can be automatic starting,after starting,to speed up to a certain,with the aid of an installed on the rotor of the centrifugal switch or other automatic control device will start winding broken,only main winding work in normal working conditions.

Therefore,starting winding can make short work.But there are a lot of time,starting winding is not broken,we call this kind of motor capacitor,single-phase motor to change this kind of motor,can be achieved by changing the position of the capacitor is concatenated.In single phase motor,the rotating magnetic field generated another method called shield electrode method,also known as single phase mask pole type motor.This made salient pole motor stator,which has two kinds of the poles and quadrupole.Each pole in a third - quarter pole face open place with full electricalmotor1.blogspot.com of small tank,the pole is divided into two parts,on the small part of the suit on a short circuit copper ring,like pole to cover up this part,so called cover pole type motor.Single-phase winding set in the entire history of the magnetic poles,each pole of the coil is connected in series,the connection must make its polarity,in turn,according to the N,S,N,S arrangement.When the stator winding current,the magnetic pole of the main magnetic flux,according to lenz's law,which through the short circuit copper ring main magnetic flux to produce a in the copper ring on the phase lag