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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2answers
2k views

Condition for max torque

My questions are these: If say a 3ph motor connected to a mains supply is rated at 1400 rpm with no load at what rpm approximately does it produce its max torque? If the same motor is run with a VFD ...
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4answers
1k views

Can I ground the negative DC bus of a variable frequency drive?

Suppose I have a typical VFD: rectifier, DC bus caps, inverter, feeding a motor. In general it would not be advisable to tie the DC bus to earth ground, because the AC line may also be referenced to ...
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5answers
11k views

Tesla Car “maximum torque at 0 RPM” - is this correct?

Tesla Model S Wiki I've been watching youtube videos on this car, and everyone states that the crazy accelleration is due to maximum torque at 0 rpm. Doing further research, this car uses an AC ...
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2answers
14k views

What is the relation between the stator current and motor rpm for an AC motor?

A 3 phase AC motor is rated values are: 970 rpm, 50Hz, 380V delta 47A. A VFD drives this motor for obtaining a constant wind-speed which rpm is proportional. The thing is when 885 rpm the stator ...
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2answers
833 views

Why this pair of IGBT's died silently?

Before some days I have taken a look at circuit which controls AC current's frequency. That circuit was a VFD which looks like: simulate this circuit – Schematic created using CircuitLab But ...
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2answers
422 views

Can I drive a three phase induction motor with this method?

I have an idea to drive induction motors in a new way. I call it Variable Torque Drive (VTD). You are all familiar with VFD which utilize variable frequency and try to keep the torque constant. This ...
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2answers
802 views

From PWM Output to Large Motor Control

This question stems from my own curiosity, so forgive any vagueness. Imagine the following scenario: We have a MCU which outputs a PWM signal to control a motor's speed and direction. We ultimately ...
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2answers
30k views

How to wire 3 phase motor to VFD

I am trying to wire a new motor to a variable frequency drive (VFD) and having some trouble figuring out how to wire the motor to the VFD. The motor is a 1 HP, 3-phase, 208-230/460 volts, and I'm ...
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1answer
68 views

When supply fan VFD starts up it causes communication problems for my energy management controller

We have an energy management system that controls the air handlers for a building. I have one unit that when the supply fan VFD starts up it cause the unit controller to start having communication ...