What Types of Motors Can Be Used with VFDs?

Do you want to know what electric motors can be used with Variable Frequency Drives (VFDs)? Keith from eMotors gets in-depth on VFDs with tips and best practices on using VFDs with electric motors, touching on topics such as lead length, line reactors, load reactors, limitations of VFDs, cooling, using encoders, overload, and more.

Generally, the types of motors that work with a VFD include:
1. AC Synchronous Permanent Magnet Motors
2. AC Synchronous Brushless Motors
3. AC Asynchronous Wound Rotor Motors
4. AC Asynchronous Squirrel Cage Motors

0:00 Introduction
0:30 Safety
0:45 Background on VFDs
1:44 What does a VFD do?
2:30 Motor Type Compatibility
3:00 Ratings to check
3:39 Protecting Bearings with VFDs
4:19 VFD Precautions

[kleindavid]

holy wow - normaly you have to watch 3902 youtube-videos in order to get usable information. This was basically the most conscise, information-dense, cometent, no-bullshit-video I might have seen in my life. Respect and thanks.

[scubabeme]

Very good primer. I recently retired from a controls engineer position. 90% of the motors we dealt with were VFD driven. We would occasionally get away with temporarily driving a non-VFD-rated motor, but that was always a temporary solution, usually ending with the motor getting rewound or outright replaced. One thing we REALLY learned was to install the AEGIS rings on them!!! It's amazing how much damage occurs to the bearings.

[BigBilly]

Excellent video, very informative! Thank you Keith.

[STohme]

Very interesting video which contains very useful information related to the topic of VFD. Probably, this video should be viewed more than one time in order to appreciate all its content. Congratulations for the quality of the video and the information included.

[brendanshield]

This guy nails it! Great presentation. Thanks from Australia

[melgross]

Very good. One of the best and clearest explanations on this topic I’ve seen. The amount of misinformation on YouTube channels (and elsewhere) is unbelievable, particularly in the area of the purchase and refurbishing of old machines such as lathes, mills, surface grinders and others. Many of these machines are many decades old with three phase motors, and often, people want to use them on single phase. I try to explain why a heavily used motor from 50 to 80 years ago shouldn’t be used with an inverter to vary speeds, but I get pushback. I intend to link to this video from now in.

I do disagree with manufacturer labeling where they don’t state inverter ready on the tag. I don’t know why not. It essentially costs them nothing to do so. I bought a motor two years ago that was advertised as such but didn’t say so. I had to call the manufacturer for confirmation. Unfortunately, many motors for sale today were designed before most manufacturers decided to make most of their offerings inverter ready. So if it doesn’t say so, you can’t know if the motor on the shelf is or isn’t. You always have to check. In ten years maybe it won’t be necessary, but for now, it really is.

[kuongsam]

Lucky to have watched this Video. Insights, insights and insights.

[roysaenz]

Great video Keith and very good speaker. 😀

[Rockall]

YT algorithm seems to find these great tubers..

[BLDEVINE]

Very nice thank you for the information.

[javierestrada]

thanks for the info we’ve been installing new roof rooftop units York they come with a drive and after six months we start noticing brand new blower motors started having bad bearings and we didn’t know why with you info we can see the problem

[neilmccarthy]

Such a brilliant upload, and thanks so much ! I am trying to specify a VFD for a 3 phase motor which is 2.2kw, 400v, 50hz, but my supply is 220v singlephase . I would be very glad of any pointers

[garbo]

We had well over a 100 plain Jane non VFD rated NEMA motors that were installed in the 1970's from 3 to 250 HP that were changed over to drives over 25 years ago. Lucky if we had two old motors a year burn out. Most did have line reactors. Most ran under 90% of rated RPM .

[mkacytchannel]

Hello sir this video is very informative. I have some question. How can identify the vfd for a direct drive motor below .5HP motor 140RPM thank you for the help.

[iacovacheiuliangheorghe]

Hello. I have a Romanian SP81sw bench lathe, it's small with an 80mm universal and it has a 0.37 kw / 380v motor. I only have a 220v network. What power should the VDF have for this motor, should I switch it to a VFD to run on 220v .Thank you!

[scottleepeters]

Thank you for this video! I can tell you have a huge knowledge base to draw from. I run an residential HVAC company and I'm getting a bit tired of replacing inverters that are 4500$ our cost due to proprietary software and communication. I feel like it shouldn't be terribly hard to build a system that can use more standard a more standard VFD and maybe simplify everything a bit. One issue I'm running into is that most of this info is directed more to 3 phase input industrial applications. All of our residential service only allows for 240v Single phase. My dream is to build something similar to the Bosch condenser that ramps up and down dependent on refrigerant pressures and doesn't need direct communication with the indoor unit past the signal to turn on and off; but do it with readily available VFDs like industrial Legos. Would you have any advice on what I need to look for in a compatible VFD and Compressor with my single phase limitation?

[wiseowldisplays]

VFD's Can also be used to create 3 phase supply for motors from a single phase input.

[Chromevulcan]

I have a spare 2hp 3ph I want to use but can't find any info on it. The part number is "US Motors p63fte-1793" and I'd like to find the right vfd. Any recommendations?

[TheTinkeringMachinist]

I plan to use a VFD to drive an old 3 phase induction motor on single phase power on a bridgeport mill. This older motor was made in 1987 with E class insulation. A grounding ring would be half the cost of a new motor. Would you recommend just running this one till it dies and then replacing with an inverter rated motor? How long would you expect something like this to run before it dies? Would you expect weeks/months, or would it be more like a few years? Not going to hold you to anything of course, just curious roughly how long you think a motor like this would last in my situation.

[philipyourno]

Can a vfd be safely used on an old Baldor 3 ph 3 hp unisaw motor? I only want to run at 3450 rpm and use my 1 ph power source.