Questions tagged [vfd]

Variable frequency drive, a three-phase AC output motor controller. Questions about vacuum fluorescent displays should not receive this tag.

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How to evaluate inverter output voltage imbalance

It's easy to evaluate the voltage imbalance of grid output voltage, but I'm not sure how to evaluate the inverter output voltage imbalance. Is it to extract fundamental wave and evaluate the voltage ...
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59 views

Choosing a motor

Long time listener, first time caller etc! Also, if you think this could be better answered somewhere else please let me know. I'm building a pottery wheel at the moment and I'm in a bit of a quandary ...
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Difference between voltage measuring from induction motor junction box and VFD output terminal

I want to measure stator voltage of VFD fed induction motor. It's common to measure from juction box, which should be the exact stator voltage of induction motor, but I wonder if it's possible to ...
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1 vote
3 answers
139 views

How can the energy produced by a generator be fed back to the motor that rotates the generator?

The drawing below shows an induction motor (IM), powered from the grid through a variable frequency drive (VFD). This IM, through a gearbox, rotates a permanent magnet synchronous machine (PMSM) ...
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10 votes
4 answers
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Why does the current carrying capability of a cable increase with temperature

I'm specifying cable for a VFD application and came across this table regarding NEC ampacities and corresponding cable size. What I found interesting is that the ampacity increased with temperature ...
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How is power consumed by an induction motor calculated based on speed (from a VFD) and torque induced by the rotor shaft?

I've been tasked with carrying out some design improvements on my company's production floor. There is a flat belt conveyor assembly line, whose movement forward movement is controlled by a single ...
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Is a change-over-switch with a VFD dangerous?

We are using a variable frequency drive (VFD) with a compressor. We added a rotary cam changeover switch (600 V/50 Hz, picture is attached) in between the compressor and the motor. The purpose of ...
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2 answers
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Regenerative Drive VFD when drive is a major % of network load?

I'm in the process of designing a new facility with about 50-60 VFDs in the 5-10 HP range, another 5 VFDs in the 100-225 HP range, and then one burly beast at 1000 HP. I've been looking into various ...
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Generator to run a compact industrial VFD (Sinamics V20)

I have a Siemens Sinamics V20 (0.5HP) industrial VFD (as picture), powering a 3-phase 0.25 HP electric motor. I work in the field and generator is the only way to have electric power. I am looking for ...
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Why AC motor driver shorts out?

I have been working in a VFD using an AC motor driver FSBB30CH60DF and making control of it using a dspic30f4011. As you can see in the attached circuit schematic, the mains supply is a single phase ...
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3 votes
3 answers
174 views

Replacing a 3-phase speed-varying drum switch with a VFD?

I am working on a stock feeder / power feeder (used with woodworking equipment). It has an 8-position drum switch to control both fwd/reverse direction as well as vary the speed. The ON positions of ...
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Controlling the speed of a single phase 4-pole induction motor

I have a Crompton Greaves single phase induction motor that powers my drill press (image below). I believe it’s rated at 1/2HP. I wanted to control the speed of this motor so that I can use the drill ...
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Benefits of using a sine wave filter with variable frequency drive

Sometimes sine wave filters are installed on the output side of a variable frequency drive (VFD.) My understanding is that these filters are advised in situations where there may be capacitance among ...
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3 answers
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Motor voltage and VFDs

Is it possible to use a motor with a lower voltage rating than the line input to the VFD that it's running on? Most VFDs have a parameter to set the maximum motor voltage, what effect does this have?
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1 answer
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What Happens if Uncharged VFD is Connected to Charged DC Bus

if the dc fuse of the uncharged drive is closed when the dc bus of other drives is charged , what happens ? Is there any risk of damaga capacitor ? As I know, capacitor can stand to very high currents ...
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Why it is required to fuse each inverter in common DC bus

I have four variable-frequency drives (VFDs) in total supplied from one largest VFD in system. The other three VFDs don't have connection to ac grid. These three VFDs are supplied from common DC bus. ...
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  • 225
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YL620 VFD terminal strip is small - wires are big. Connector options?

I'm attaching input power (240V single phase) and motor load (3-phase, variable frequency) wires to a terminal strip of a Variable Frequency Drive controller (YL-620). The power rating for the device ...
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VFD max current rating less than motor peak current - problem?

Whats the worst that could happen if using a QUALITY 8amp VFD - single phase input, 230v, vector controlled - on a industrial 3 phase motor with peak current rating of 50 amps. Do VFDs have the ...
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2 answers
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3 phase motor VFD frequency / current draw help needed?

I am planning to covert a 1920 Drummond B type lathe to 3 phase motor / VFD combo and am trying to understand the math involved with VFDs mainly relating to frequency and current draw. How do they ...
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2 answers
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Help choosing 3 phase motor and VFD for mini lathe project

I bought a 101 year old mini-lathe (Drummond B type) and from what I've seen and read online it should be possibe to bring this lathe into the 21 century. In my most extreme vision I would like to ...
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2 answers
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How can i choose the right VFD for an electric motor?

I have a 1.5kW three phase electric motor that is in a delta configuration. This motor has a motor voltage of 230/400V and a rated current of 5.9/3.4A. What sort of VFD should i be looking for that ...
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Use closed loop torque control based on motor position to simulate a dynamic load

The goal is to use servo + gearbox to simulate a screwing process millions of times. A screwing process is characterized by a low torque at first (the screw enters the material) and once the screw ...
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2 answers
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Table jitter on 40 ft planer mill at certain low feedrates with new 40 hp 3-phase motor and 50 hp ABB drive

The display on the drive shows 26 amps with little variation at all speeds. At 176.14 RPM it shows -9.2% motor torque, 25.63 amps. At 977 RPM it shows 26.04 amps and 2.4% torque. The motor spec ...
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1 answer
114 views

Induction motor 'droop control' on multi-motor coupled loads

When using droop control to balance the torque across multiple motors driving a coupled mechanical load such as a chain conveyor, what is the actual variable that is being altered by each drive? From ...
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8 votes
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1k views

Why do variable frequency drives (VFDs) need so much information?

I'm an electricians apprentice at a mine. I understand the basic operation of variable frequency drives (VFDs), rectification, filtering, and pulse width modulation. But, at the heart, all they're ...
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Pole counts for VFD driven induction motor

What is the significance of pole count of IM if it is driven by a VFD? If we are using the power supply frequency (50Hz or 60Hz), the pole counts matter in terms of torque and synchronous speed. But ...
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1 answer
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What would cause DC bus voltage on my VFD when the disconnect is off

125 hp 480 vac HMax VFD. Controlling a pump motor. Motor is not spinning and line to the VFD is disconnected. I was putting the output wires back on the VFD, when moving the second one into place, ...
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8 votes
4 answers
2k views

Can I run a VFD off a generator?

I want to power a three-phase 5hp well pump with a VFD. I want the VFD both to serve as a soft start, and to allow variable speed operation of the motor. Two different pump salesmen have told me that ...
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1 vote
0 answers
68 views

Why does reciprocating compressor's motor starting winding have high voltage than running winding

I want to know why the starting winding of (2 ton) reciprocating compressor's motor have high voltage than running winding? I have attached the voltage that I have captured from oscilloscope. This ...
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1 answer
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Building a VFD for a split phase (capacitor run) motor?

I'd like to get variable speed on a very tiny lathe (Taig, 4" swing). I've got a dishwasher motor I'm planning on using for it, which is rated for 3600rpm at 60Hz (it's about 1/5HP). But it's a ...
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3 answers
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EMC Cable shield used as PE wire, great idea or not?

In order to save on cabling, our company uses 3 wire EMC cables to connect electric machines to their VFD's. Some folks in our company think we should really use a dedicated ground wire, many are of ...
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How do VFDs limit the starting current of the motor?

I have a 5 HP three phase motor. I am going to install a variable frequency drive (VFD) for speed control. I know that VFDs are used to soft start motors. How do VFDs limit the starting current of the ...
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1 vote
0 answers
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Is V/F maintained constant even in field oriented control or vector control drive of PMSM motors?

I understand that in scalar control V/F is maintained constant below rated speed, as Vector control drive is also a variable frequency drive, I would like to know whether V/F is maintained constant ...
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1 answer
69 views

VFD and motor compatibility

I am looking for a VFD. The motor has following specifications:Motor nameplate YE2-1329-4 and JB/T11707-2013 5.5 kW, 400V, Δ, 11.3 A , 50Hz, CosΘ 0.82, IP 55, 1460 rpm, 87.7. Is above motor ...
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0 votes
2 answers
102 views

380V Wye on motor nameplace,VFD manual requires 220V delta. Will it work?

I removed a motor (nameplate attached) from an eddy current drive. My intention was to replace the controller with a VFD and remove the clutch assembly. The motor obviously ran at full speed with each ...
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1 vote
1 answer
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Maximum Voltage That Can be Applied to a Motor

I was reading about 87Hz technique. I saw we can configure the drive for a motor 400Y/230D as 400V /87hz. I know v/hz ratio should be kept constant and when we configure drive as 400V and 87 Hz and ...
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0 answers
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Measuring voltage in VFD

I an troubleshooting my chiller because I fried my compressor. I have done clues of what could go wrong, but want to discard over voltage. I have a Mitsubishi VFD. That I take 240 and convert to 240 3 ...
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49 views

Effect of PWM output from Variable Frequency Drive to PSC motor

I looked at VFD diagram and seem like it use Sine-PWM Output without any filter to drive psc single phase ac motor Inductance and capacitance seem to work with pure sine wave but PWM output have a lot ...
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3 votes
2 answers
301 views

How to choose and wire a Variable Frequency Drive [closed]

I have a 1.5 HP 3PH 240V Leeson motor that I want to drive my lathe, but I want to vary the speed. I asked a question on this site about a month ago about how to do that and the recommendation was a ...
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0 answers
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What scheme would you indicate for a nobreak system with variable frequency output?

I'm pretending to make a system that charge batteries (or a single battery) and then produces 3 independent AC outputs (all having the same common, in a star connection). But I want to have ...
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0 votes
1 answer
2k views

Understanding VFD speed control input using a potentiometer

I am working on hooking up a potentionmeter as a speed control input to a variable frequency drive. Here is are the diagrams from the VFD manual: (Its a Lenze AC Tech SMVector ESV112N01SXB; full ...
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1 answer
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VFD Motor Bidirectional Control

So I have a control panel which controls the speed and direction of a motor in a sliding mechanism. the direction can be inverted using a tri-state selector on the panel. the selector input is a ...
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1 answer
518 views

VFD for a 3-phase delta-connected 415V~ motor

When a motor starter is to be replaced by a 3-phase 415V~ VFD, can the existing motor be used without changing its winding configuration (star/delta)? The motors are from different manufacturer ...
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1 vote
2 answers
48 views

What exactly is 1.x and 2.0 power scalar V/f control in VFDs?

These are terms that I have come across in multiple operating manuals for VFDs and usually, they just mention that it's used for variable torque applications. My doubt is "what exactly is it?&...
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1 vote
2 answers
98 views

Is upsized reactor allowed for the comparitively less motor HP?

We have a LV-MCC in our commercial outlet having a 480 VAC, 15 HP VFD with line and load reactors in series with it. The VFD is sized for 22.0 A (normal duty), the motor has a horsepower rating of 10 ...
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1 vote
2 answers
535 views

Tesla Model S inverter DC bus voltage

I was recently researching about this Telsa electric car inverters where i found one intresting thing. Usually in the voltage source inverter the DC bus voltage will be around 600 to 650 V considering ...
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1 vote
1 answer
29 views

Delta Servo Drive 220V/400V Series

ASDA-A2 Delta Servo Drives including two types: 220V and 400V series that it seems the difference is input voltage of the Servo Derive. but i doubt 220VAC or 400VAC is line to line voltage or line to ...
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1 vote
2 answers
1k views

Motors Delta/Star connections to VFD

I've selected 230/400V motors (delta/star) and corresponding 400V VFDs for pump motors. Now I've been asked why I haven't selected 400/690V motors (delta/star), that are the standard and usually ...
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0 votes
1 answer
96 views

AC Induction Motor Slip and Torque control Vs V/f control

I am trying to understand this github code for speed control of AC Induction Motor. It calculates slip value to adjust the speed of motor. I wonder if its the same thing that is called constant V/f ...
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1 vote
1 answer
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4-20 mA output from Arduino for VFD

I'm a beginner with electronics, so everything has to be explained in simple terms to me. I have an Arduino with a program which provides a value via the Analog output, so that is anything from 0-5 V....
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