3 phase?

SBuzek gave you the correct and short answer. The input for a VFD can be 115v single phase and outputs 230v 3 phase.

BTW, I still think of you when I use the "upsetting plate" you brought me. Thanks again.
 
99% of the time, yes.

Inputs can also be 230VAC single phase, 3 phase out, or they can even be 3 phase in AND out. Some even go up to 480V, so make sure you get the right motor AND vfd.
 
the other option hardly ever discussed is to use a DC motor with a DC variable speed control. that said, if you hunt the internet, you should be able to find an industrial grade inverter(110/220 input with 3 phase 220 output)that also has a variable frequency function for $200 or less(I just bought a 3hp Leeson for $150 delivered. then shop and you can find industrial grade motor to go with it for $200 or less. there are many places on line that sell last years model for less than 1/2 of current model. we are talking motors and motor controls, not computers. very little has changed in the way motors are made(other than some companies moving their factories off shore to save a buck) in the last 50 years.
scott
 
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I just bought a 2hp chinese VFD off of Ebay for about $125. It's not TEFC so I have to keep it in a cabinet, but it's actually a pretty decent VFD. The manual it came with has a few rough spots in it, but it's extremely programable and upgradeable. It's even got a spot for installing an on board potentiometer for variable frequency (speed) control.

I looked up some reviews on this VFD, and it's mostly getting good reviews from guys using them to run lathes, mills, surface grinders, etc...
 
Andrew,
Ok I am a bit dents, literally! Anyway, arex you saying that you got a 2 hp vfd? Or is it a motor? Can you please explain what you bought and what you needa to get going? Thanks, Rex
 
Andrew,
Ok I am a bit dents, literally! Anyway, arex you saying that you got a 2 hp vfd? Or is it a motor? Can you please explain what you bought and what you needa to get going? Thanks, Rex
VFD's dont have an actual HP but often times they are specified as able to control a motor up to a certain HP. So I beleive what they mean when they say they got a 2hp VFD they mean it will run up to a 2 hp motor.
 
A VFD=Variable Frequency Drive. This is the digital speed controller box. It is separate from the motor and is often called a "drive" to be extra confusing.

A 3phase motor is required for use with a VFD. These are really common in industrial use and often lower in cost than a 1phase (house hold type current)

A VFD will convert your household current (120v or 220v) 1phase electrical current into 3phase electrical current and control the speed of the motor via digital circuit boards.
 
VFD's dont have an actual HP but often times they are specified as able to control a motor up to a certain HP. So I beleive what they mean when they say they got a 2hp VFD they mean it will run up to a 2 hp motor.

That's correct, and sorry if my post was a little confusing. For most intents and purposes, a VFD rating has to do with circuit protection.

The VFD I purchased can be programmed to run up to a 2 hp motor, but can also be used for a smaller motor. I actually wired an outlet to my VFD and run both a surface grinder and a mill with mine (seperately). P


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I think we are missing a term, inverter. It is an inverter, whether solid state or rotary, that can convert single phase 110 or 220(standard household power) to 220 vac 3 phase power. Some, like the Leeson I bought, can change the output frequency so it will act as a VFD. The VFDs we have at the office are all 3 phase in, 3 phase out, with input voltage programmable. Some use 460 vac(500 vac actual) some use 380(on some european equipment).
The attraction of a VFD is that it is the easiest way to control speed of a motor. turn a knob or press a button and the motor speed goes up or down. You do not have to change how the motor is mounted.
The other methods would be belts with different size pulleys, chains with different size sprockets, or gear boxes. these will give you a fixed speed less than or greater than motor speed. they can be complicated, difficult to install, need enclosures (to protect you) , and must be checked and serviced on regular intervals. belts wear out, chains stretch, and gear boxes need oil. I found when designing my disc sander, that to do it properly and have more than one speed, I would pay almost as much for the parts to build a 4 speed belt system (there is a lot more than 2 pulleys and a belt) as I did for the 3hp inverter/vfd.
 
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