HAI YAN Variable-frequency drive-lx2000-01

Ref Price:
Loading Port:
Ningbo
Payment Terms:
TT OR LC
Min Order Qty:
1 unit
Supply Capability:
10 unit/month

OKorder Service Pledge

Quality Product

Order On-line Tracking

Timely Delivery

OKorder Service Pledge

Credit Rating

Credit Services

Credit Purchasing

Share to:

Product Description:

AC line harmonics

It is also possible to replace the standard diode-bridge rectifier with a bi-directional IGBT switching device bridge mirroring the standard inverter which uses IGBT switching device output to the motor. Such rectifiers are referred to by various designations including active infeed converter (AIC), active rectifier, IGBT supply unit (ISU), active front end (AFE), or four-quadrant operation. With PWM control and a suitable input reactor, an AFE's AC line current waveform can be nearly sinusoidal. AFE inherently regenerates energy in four-quadrant mode from the DC side to the AC grid. Thus, no braking resistor is needed, and the efficiency of the drive is improved if the drive is frequently required to brake the motor.

Two other harmonics mitigation techniques exploit use of passive or active filters connected to a common bus with at least one VFD branch load on the bus. Passive filters involve the design of one or more low-pass LC filter traps, each trap being tuned as required to a harmonic frequency (5th, 7th, 11th, 13th, . . . kq+/-1, where k=integer, q=pulse number of converter).

It is very common practice for power companies or their customers to impose harmonic distortion limits based on IEC or IEEE standards. For example, IEEE Standard 519 limits at the customer's connection point call for the maximum individual frequency voltage harmonic to be no more than 3% of the fundamental and call for the voltage total harmonic distortion (THD) to be no more than 5% for a general AC power supply system.

Long-lead effects

The carrier-frequency pulsed output voltage of a PWM VFD causes rapid rise times in these pulses, the transmission line effects of which must be considered. Since the transmission-line impedance of the cable and motor are different, pulses tend to reflect back from the motor terminals into the cable. The resulting voltages can produce overvoltages equal to twice the DC bus voltage or up to 3.1 times the rated line voltage for long cable runs, putting high stress on the cable and motor windings, and eventual insulation failure. Note that standards for three-phase motors rated 230 V or less adequately protect against such long-lead overvoltages. On 460 V or 575 V systems and inverters with 3rd-generation 0.1-microsecond-rise-time IGBTs, the maximum recommended cable distance between VFD and motor is about 50 m or 150 feet. Solutions to overvoltages caused by long lead lengths include minimizing cable distance, lowering carrier frequency, installing dV/dt filters, using inverter-duty-rated motors (that are rated 600 V to withstand pulse trains with rise time less than or equal to 0.1 microsecond, of 1,600 V peak magnitude), and installing LCR low-pass sine wave filters. Regarding lowering of carrier frequency, note that audible noise is noticeably increased for carrier frequencies less than about 6 kHz and is most noticeable at about 3 kHz. Note also that selection of optimum PWM carrier frequency for AC drives involves balancing noise, heat, motor insulation stress, common-mode voltage-induced motor bearing current damage, smooth motor operation, and other factors. Further harmonics attenuation can be obtained by using an LCR low-pass sine wave filter or dV/dt filter.

Dynamic braking

See also: Dynamic braking and Regenerative braking

Torque generated by the drive causes the induction motor to run at synchronous speed less the slip. If the load drives the motor faster than synchronous speed, the motor acts as a generator, converting mechanical power back to electrical power. This power is returned to the drive's DC link element (capacitor or reactor). A DC-link-connected electronic power switch or braking DC chopper controls dissipation of this power as heat in a set of resistors. Cooling fans may be used to prevent resistor overheating.

Dynamic braking wastes braking energy by transforming it to heat. By contrast, regenerative drives recover braking energy by injecting this energy into the AC line. The capital cost of regenerative drives is, however, relatively high.

Regenerative drives

Line regenerative variable frequency drives, showing capacitors (top cylinders) and inductors attached, which filter the regenerated power.

Simplified Drive Schematic for a Popular EHV

Regenerative AC drives have the capacity to recover the braking energy of a load moving faster than the designated motor speed (an overhauling load) and return it to the power system.

Cycloconverter, Scherbius, matrix, CSI, and LCI drives inherently allow return of energy from the load to the line, while voltage-source inverters require an additional converter to return energy to the supply.

Regeneration is useful in VFDs only where the value of the recovered energy is large compared to the extra cost of a regenerative system, and if the system requires frequent braking and starting. Regenerative VFDs are widely used where speed control of overhauling loads is required.

Some examples:

  • Conveyor belt drives for manufacturing, which stop every few minutes. While stopped, parts are assembled correctly; once that is done, the belt moves on.

  • A crane, where the hoist motor stops and reverses frequently, and braking is required to slow the load during lowering.

  • Plug-in and hybrid electric vehicles of all types

Send a message to us:

Remaining: 4000 characters

- Self introduction

- Required specifications

- Inquire about price/MOQ

Q:what is an electrical ark?
You mean an electrical arc. That's what happens when there is a short circuit. Electricity flows through air, ionizing the air. There is a flash, noise, and a physical blast. More appropriately, the arc projects an enormous amount of heat that can cause severe burns to nearby unprotected skin. Industry has evolved a set of practices to quantify the thermal energy generated by arc flash, and to prescribe the protective clothing that personnel must have in order to work on energized equipment.
Q:How to create an electrical connection outlet out of thin air?
Hmmm, for modest loads, you can use induction but that needs modifications to the equipment you are using AND needs the drive coils embedded in the walls of the building you are in. It does work quite well though :) Tesla had some quite good ideas about tranmistting power but again, the method is not something too practical to use in your everday building. Sorry :(
Q:Impala trunk electrical equipment?
On Star receiver/ broadcaster GPS tracking for crash assistance.
Q:Marine corps MOS 1142- Engineer Equipment Electrical Systems Technician?
Well you won't be a Soldieryou will be a Marine 1142 is a High Tech JobElectronicsCircuit boards and the like Great Background in Electronics for a Civilian Career Do not waste your Time in the CorpTake every Electronics course you can Go to Night School and stay out of the Bars and Strip Joints I was a Sgt 1141/42 in Vietnam Earned an EE Degreeowned a successful Business now RetiredX2 You will be assigned to a Utilities Platoon (Extremely Few in Numbers) Within an Engineering Battalion Probably the Least numbers of Marines in any Outfit Must Maintain and Repair any and all Electrical Generators and Pumpswithin the Command you are assigned to ie: 7th Engrs was assigned to the 1st MarDiv in Vietnam Maybe assigned to an MEB aboard shipFMF and make Landings and set up your equipment SEMPER FI !!!!
Q:Dodge problem?
If you didn't have the electrical problems, I'd say it was the transmission. Since you have electrical problems, it's more likely that there is a loose or bad connection between your battery and alternator. Your car is 10 years old, so, presumably, you've changed the battery at least once during that time. Since the industry standard is every 5 years, you might be due for a change! With any luck changing the battery will fix the loose cable connection. Of course, it could be the alternator, too, as well as a bad ground. Use a voltmeter with all the appliances running, to see if you get at least 15 volts; it is normal for the needle to oscillate a tiny bit back and forth. If it's below 15 volts, your alternator may need to be replaced, or, a wire is loose at that end. In some cars, low electrical output can confuse the computer. BE VERY CAREFUL WHEN HANDLING CAR BATTERIES AND OTHER ELECTRICAL EQUIPMENT!!! Good luck!
Q:my appliance says it needs a 15 amp NEMA 5-15R outlet. picture looks like houselhold one. Are they the same?
It is a normal 120VAC outlet that is required. If it is a replacement appliance plug it into the outlet its predecessor used. If there are any problems you may find the main breaker trip, and at that point you can look into a dedicated circuit. Otherwise plug it in and be happy.
Q:strange option on my HDTV?
The two choices are PC Personal Computer or DTV Digital TV. Depending on what you're doing will determine the mode of operation. When in TV mode you use the TV controls to set the width and aspect ration of the display. When you're using the PC the graphics card will normally set the width and aspect ration. Ever notice that when you change resolution on a normal PC monitor that 640X480 uses just as much screen as when it's set to 1072X768. The graphics card adjusts the size. DTV mode will have the internal controls in your TV controlling the size and PC will have the graphics card in the PC controlling it. As I'm writing this another possibility came to mind. You may have an ATSC tuner (digital tuner) built into your HDTV. The TV may simply be asking you which source you want it to look at. In other words do you want to continue watching TV using the internal tuner or switch to looking at the PC information that is now available. Your best bet is to pick up the owners manual and read the section that tells you about hooking up your computer to the monitor. I'm sure that will explain what your asking for.
Q:what is the average salary for an entry level electrical engineer?
Entry Level Electrical Engineer Salary
Q:What is this piece electrical equipment that hospitals use.?
AED : automatic external defibrillator
Q:Is a surge protector necessary?
It should already be built into the laptop. However, you don't need a $100 surge protector, computer stores have many for less than $20 (or hardware stores). Try there first, it wouldnt hurt to have extra protection.

1. Manufacturer Overview

Location
Year Established
Annual Output Value
Main Markets
Company Certifications

2. Manufacturer Certificates

a) Certification Name  
Range  
Reference  
Validity Period  

3. Manufacturer Capability

a)Trade Capacity  
Nearest Port
Export Percentage
No.of Employees in Trade Department
Language Spoken:
b)Factory Information  
Factory Size:
No. of Production Lines
Contract Manufacturing
Product Price Range