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I am in the process of designing a harmonic filter for a client and to tell the truth, if you never done this before, it is much more complicated than it seems.

You have to know if the source of harmonic is a voltage or current source. The best is to know the equipment generating them and be able to estimate precisely the amount of harmonic present in the system. If you are lucky it is a current source and you may wish that your filter will not change the amount of harmonics. Then, ...

To properly answer this question, we would need to have the actual motor ratings and operating load conditions, I.e.; nameplate voltage, frequency, amperes & service factor. Actual operating conditions would be; operating voltage, operating amperage & type loading (constant, cyclic/constant etc.). Generally, a motor with a nameplate rating of 3ph 230 volts can operate as low as 3ph 207 (+/-10%) system volts. However, if the operating conditions are a heavy load at or near nameplate fu ...

The most common method used by manufacturers is to anneal the electrical steel after the lamination has been punched to its final shape (e.g. the diameters are fixed, the slot geometry is complete, and any "retaining" geometry is complete). Due to the temperatures involved (750 C or so), it is something that is done at the end of the process whereby the lamination is created - well before any actual construction (e.g. stacking) of the stator or rotor begins.

Generally speaking, the ...

In the datasheet of a squirrel cage induction motor, rated stall time- 18/30Sec (cold/hot) & Acceleration time- 9/15Sec (100%/80% of rated Volt) are given. In motor protection, it has stall protection, number of start limitation & thermal overload. Since the motor under subject is driving a fan, it takes longer acceleration time & tripping in thermal overload every time during startup.
1. What is the Acceleration time-9/15Sec given in datasheet? Is it the maximum the motor c ...

Three phase asynchronous AC motor is widely used in industrial and agricultural production due to its simple structure, low cost, easy maintenance and easy operation. 3-phase AC motor uses 3 phase power supply (3 ph 220v, 380v, 400v, 415v, 480v etc.), but in some actual applications, we have single phase power supplies only (1 ph 110v, 220v, 230v, 240v etc.), especially in household appliances. In the case to run the three phase machines on single phase power supplies, there are 3 ways to do ...

Shaft voltage is directly attributable to two different things: dissymmetry in the magnetic path, and generation of a static charge.

Internal to the machine, the construction of the magnetic circuit (laminations and frame) and the layout of the conductors (winding) contribute to a potential dissymmetry in the flux path. After all, most coils are hand-made - which leads to marginal, but noticeable differences.

External to the machine is the source waveform. If it is disto ...

Let's look at the question in another light and see if it makes sense.

For some reason, you have access to perhaps 5 separate vehicles - different manufacturers (possibly), different makes and models (almost certainly). You install a dash cam on each vehicle, and wire the cam AND the controls (steering, brakes, accelerator) to a wireless robotic controller that gets its input from a single remote source.

The vehicles are in different parts of the city - or maybe even jus ...

Assume that when you changed the frequency from 50 to 60 Hz that you mean the rated frequency but you then ran the motor at the same speed. By doing this you have altered the motor set up calculations that could have changed two items giving a different resistance.

The first is that the slip speed would be different that gives different equivalent rotor resistance values when referred to the stator. The equation is actual rotor resistance / slip. The other is that the skin effect f ...

Load Commutated Inverter (LCI) is a system with an input thyristor bridge and an output thyristor bridge. The input bridge is naturally commutated by the AC supply and supplies DC current with harmonics into a large inductor. The output bridge operates at low speed by turning on a set of 2 thyristors to pass the DC current into the generator's stator to cause it to rotate. As it rotate the first set has to be switched off and another pair turned on to keep the generator turning.

Ab ...

Stepper technology has come a long way and certainly can be a good choice for many applications. However, there are considerations such as torque ripple and the fact they will slip position when over torqued. Some systems can detect the slip (even without an encoder) which is good, but unlike a servo will not create and correct the following error. If you add an encoder then more is possible but the control is still open loop, but you then have the ability to know if it slipped and how much. ...

Why the frequency of power supplies in European and Asian countries is 50Hz, while American countries use 60Hz power supplies? What is the basic of the standard? What are the advantages and disadvantages of 50Hz and 60Hz power supply? In addition, why the airport and aircraft use 400Hz frequency?

In fact, there is no big difference between 50Hz and 60Hz, only the generator speed has slightly difference. Ch ...

For induction motors if you run the motor at a high flux level the winding flux magnetizing current has a significant third harmonic content that can flow around the Delta winding without appearing in the lines to the VFD.

This is good for the flux waveform but it is not seen by the VFD internal current sensors so you can over-flux and get high motor winding currents giving motor overheating with no indication in the VFD. So with Delta I recommend winding current sensors but this i ...

From first principles and trying to make it really simple. In an inductive circuit, the difference in potential causes a current to flow. As the current flows it induces a magnetic field. If this magnetic field in interacting with other magnetic fields (Itself or another) the other magnetic field suppresses the buildup of the magnetic field that this current is trying to establish. This inhibits the current rise as the voltage increases. In a DC circuit this happens at switch on and to a less ...

"Unearthed neutral" is the NORMAL configuration for AC electrical machines, regardless whether they are connected "delta" or "wye". In the case of delta, there is no neutral connection available. In the case of wye, the neutral point is physically located somewhere within the machine winding - but is not brought out to the world at large.

"Unearthed" neutral systems are the PREFERRED network for marine installations (particularly shipboard), since it is disadvantageous to pass curr ...

The answer depends upon the type of motor. A synchronous motor can usually be driven as an alternator by simply substituting a prime mover for the mechanical load. Things are less clear for an asynchronous/induction motor since it will depend upon whether it is attached to a three-phase supply or not.

If there is a three phase source then the prime mover has to operate at greater than synchronous speed, however its output frequency will be locked to the line frequency, assuming th ...

Depending on your local electrical code, if you need a grounded (earthed) system, you can use a 400V-Delta to 208/120V WYE transformer to feed a variable frequency drive (VFD), and then set it a 60Hz to supply 208V 60Hz to the motor. Although I do not normally recommend it, if it is appropriate for you to run the system ungrounded (unearthed), then you can feed the VFD with through a 400V-Delta to 230V-Delta transformer and then supply the motor with 230V 60Hz power from the VFD. (As with mos ...

The torque speed curves are completely different between an induction motor and slip ring motor. You need to understand the differences. If you have selected your slip ring motor to limit starting currents you can short out the slip rings and run your motor but the starting torque is reduced unless you use some features on the VFD to boost starting torque.

If you are using it as torque control on a crane then y ...

With larger motors it is normal to insulate the NDE bearing. The normal reason is that the majority of movement will come from the DE. This is done by machining out the end shield to take a sleeve into which your bearing will sit. Material selection is vital. Please be aware that this insulating requirement would include any lubrication, vibration, temperature monitoring equipment and the like. If your motor is very big the insulation material sits between the base and the pedestal but again ...

From first principle, the diesel engine can run very hard for a short period of time. This is called the STANDBY time. The PRIME POWER is when the engine runs at load factor not exceeding 80% power for any 24 hour period. Then there is the continuous rating which is BASE LOAD. This causes problems when you order a STANDBY generator at say Engine Gross Power of 1437kWm Net Engine power of 1395kWm which gives 1325kWe. Where m = mechanical and e = electrical. For the same set up, PRIME POWER Gro ...

Variable frequency drives should be protected by fuses. Why? Because the VFD itself has all the protection you require for your motor so the only item you are protecting is the Rectifier and DC bus. Then you will find it is actually really impossible to protect it as when it has a fault it is generally catastrophic and all you wish to do is to remove the faulty VFD from the network to enable the rest to continue. This must be as fast as possible to limit the damage and MCBs don’t really ...