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I can recommend adding a surge protection device at the electric panel for whole house protection.?

https://a.co/d/2GwZnZX

Put one of these on and if your house or utility power supply cable gets hit by lightning, this will save all your appliances and tools. Immediately after the lightning strike remove and replace the protector as it will likely be used up.

Get

Show quoted text

From: [email protected] <[email protected]> on behalf of cwlathes via groups.io <carvelw@...>
Sent: Tuesday, March 25, 2025 12:47:53 PM
To: [email protected] <[email protected]>
Subject: Re: [emcoV10lathe] vfd load reactor suggestions?

?

Hi Len

Some VFD’s are noisier than others so you seem to have made a fortunate choice

It also depends on the motor’s history

The Emco motor tends to run hot so if it was previously in an environment where it was used a lot , then the insulation might also have suffered over time and be more prone to VFD or other spike damage

Lightning is also a hazard so not a good idea to use your machines in a storm? . .? also unplug them when not in use if in a lightning prone area like the one I live in ? ?

Regards,

Carvel

?

From: [email protected] [mailto:[email protected]] On Behalf Of Len Sherman via groups.io
Sent: Tuesday, March 25, 2025 5:10 PM
To: [email protected]
Subject: Re: [emcoV10lathe] vfd load reactor suggestions?

?

Maybe I've been living dangerously, but I've run that same motor (on a VP10) from a VFD with no load filter for 10 years with no hint of a problem. I also have a VFD on an old BP clone mill of similar age, also with no issues.

#27528

I agree with all that Carvel said and would add that sample of 1 (well two in Carl's case) is hardly a representative one. And it works both ways, if say 99% of the motors are known to run for years on VFD without a hitch and you happen to be the owner of the one that packs it up, it's not gonna make a difference to you that the other 99 are fine.

As far as I know, there were 3 manufacturers of these motors, in small series over a long time. It's quite possible each unit is completely different in how much VFD (ab)use it can take.

Running a VFD adds a bit of risk, but so does running a machine tool at all. You accept it, mitigate it or reject it (by not using a VFD).

Unfortunately we don't have good enough data to tell you how big of the risk it actually is. Plan on the contingency where it might be possible your motor burns up. I personally don't think it's a big issue in a hobby shop, but I'm first to point out that my opinion is based more on wishful thinking than on hard data :)

Regards

Vedran

Show quoted text

On Tue, Mar 25, 2025 at 5:58?PM Andrei via <calciu1=[email protected]> wrote:

I can recommend adding a surge protection device at the electric panel for whole house protection.?

Put one of these on and if your house or utility power supply cable gets hit by lightning, this will save all your appliances and tools. Immediately after the lightning strike remove and replace the protector as it will likely be used up.

Get

From: [email protected] <[email protected]> on behalf of cwlathes via <carvelw=[email protected]>
Sent: Tuesday, March 25, 2025 12:47:53 PM
To: [email protected] <[email protected]>
Subject: Re: [emcoV10lathe] vfd load reactor suggestions?
?

Hi Len

Some VFD’s are noisier than others so you seem to have made a fortunate choice

It also depends on the motor’s history

The Emco motor tends to run hot so if it was previously in an environment where it was used a lot , then the insulation might also have suffered over time and be more prone to VFD or other spike damage

Lightning is also a hazard so not a good idea to use your machines in a storm? . .? also unplug them when not in use if in a lightning prone area like the one I live in ? ?

Regards,

Carvel

?

From: [email protected] [mailto:[email protected]] On Behalf Of Len Sherman via
Sent: Tuesday, March 25, 2025 5:10 PM
To: [email protected]
Subject: Re: [emcoV10lathe] vfd load reactor suggestions?

?

Maybe I've been living dangerously, but I've run that same motor (on a VP10) from a VFD with no load filter for 10 years with no hint of a problem. I also have a VFD on an old BP clone mill of similar age, also with no issues.

#27542

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Greetings guys,

I've been following the "reactor" thread with some interest.? I too have been using a VFD (TECO FM50)? for circa 2 decades on a Maximat 7.
I appreciate that my experience does not apply to all.? Also I understand that these motors have different histories, and in fact fail without
the help of a VFD.???? BTW, mine runs cool as a clam on the VFD and that was not the case while using the capacitor hack to approximate 3 phase.

One factor that appeared to be missing from this thread is an honest to goodness measurement of the the VFD driving the motor.
I'm a retired EE that worked as a development engineer in the Test and Measurement world for over 30 years.
To this end, a 180:1 differential voltage measurement adapter was created to drive a LeCroy 9350AM O'Scope under HPIB control
and interfaced to MATLAB.

Here are some results .......? I sure hope the screen shots come through !

1)? This one is very telling. The YELLOW is the raw voltage across one phase of the the FM50:

Note that peaks approach 500V. Also note that the resemblance to a sine wave is coincidental.
But pass this waveform through a low pass filter, and behold ... a pretty darn nice sine wave is produced !
Also, the (standard) 208V phase voltage should produce peaks of sqrt(2)*208 = 294V and the above (low passed data) is mighty close (285V) even with the "flat topping".?
Zooming in:

You can see that what appears to be some high frequency hash is actually a sequence of variable duration pulses that "fine tune" the larger steps in the FM50 output.
Pretty clever.?

As for me, no filtering need be applied. If these voltages break down the motor's wire insulation, that was probably going to happen VFD or no VFD.
Your mileage may vary !!!

Best regards from N. CA.

Dick?
--

I'd rather have questions that can't be answered than answers that can't be questioned. ? Richard Feynman
For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled. ? Richard Feynman
Available energy is the main object at stake in the struggle for existence and the evolution of the world. Ludwig Boltzmann (1844-1906)
Who's bright idea was it to put every idiot in world in touch with every other idiot? ? ? ? ? ? P.J. O'Rourke
Illegitimi Non Carborundum

#27544

开云体育

Hi Dick

?

They say sometimes a picture is worth a thousand words? . . thanks for sharing ?

Glad to hear your motor has survived

As a matter of interest what make of motor do you have on your lathe ?

Regards,

Carvel

?

Show quoted text

From: [email protected] [mailto:[email protected]] On Behalf Of Dick Benson via groups.io
Sent: Thursday, March 27, 2025 12:32 AM
To: [email protected]
Subject: Re: [emcoV10lathe] vfd load reactor suggestions?

?

Greetings guys,

I've been following the "reactor" thread with some interest.? I too have been using a VFD (TECO FM50)? for circa 2 decades on a Maximat 7.
I appreciate that my experience does not apply to all.? Also I understand that these motors have different histories, and in fact fail without
the help of a VFD.???? BTW, mine runs cool as a clam on the VFD and that was not the case while using the capacitor hack to approximate 3 phase.

One factor that appeared to be missing from this thread is an honest to goodness measurement of the the VFD driving the motor.
I'm a retired EE that worked as a development engineer in the Test and Measurement world for over 30 years.
To this end, a 180:1 differential voltage measurement adapter was created to drive a LeCroy 9350AM O'Scope under HPIB control
and interfaced to MATLAB.

Here are some results .......? I sure hope the screen shots come through !

1)? This one is very telling. The YELLOW is the raw voltage across one phase of the the FM50:

Note that peaks approach 500V. Also note that the resemblance to a sine wave is coincidental.
But pass this waveform through a low pass filter, and behold ... a pretty darn nice sine wave is produced !
Also, the (standard) 208V phase voltage should produce peaks of sqrt(2)*208 = 294V and the above (low passed data) is mighty close (285V) even with the "flat topping".?
Zooming in:

You can see that what appears to be some high frequency hash is actually a sequence of variable duration pulses that "fine tune" the larger steps in the FM50 output.
Pretty clever.?

As for me, no filtering need be applied. If these voltages break down the motor's wire insulation, that was probably going to happen VFD or no VFD.
Your mileage may vary !!!

Best regards from N. CA.

Dick?
--

I'd rather have questions that can't be answered than answers that can't be questioned. ? Richard Feynman
For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled. ? Richard Feynman
Available energy is the main object at stake in the struggle for existence and the evolution of the world. Ludwig Boltzmann (1844-1906)
Who's bright idea was it to put every idiot in world in touch with every other idiot? ? ? ? ? ? P.J. O'Rourke
Illegitimi Non Carborundum

#27545

开云体育

Hi Carvel, et. al.

Glad you found the VFD data of some interest.?
One minor error is the low pass filter corner frequency was 4kHz, not the 10kHz reported on the graphic.

The motor is:

Best regards,

Dick

--

I'd rather have questions that can't be answered than answers that can't be questioned. ? Richard Feynman?
Illegitimi Non Carborundum

#27546

开云体育

Dick – thanks

It might be interesting to develop a database of those motors which survive the VFD vs those which don’t

On the other hand there are so many variables , it might be a meaningless exercise ? ?

Anyway if those members using VFD’s would like to share their motor details with us it might be interesting to see if there is any pattern

Regards,

Carvel

?

Show quoted text

From: [email protected] [mailto:[email protected]] On Behalf Of Dick Benson via groups.io
Sent: Thursday, March 27, 2025 4:19 PM
To: [email protected]
Subject: Re: [emcoV10lathe] vfd load reactor suggestions?

?

Hi Carvel, et. al.

Glad you found the VFD data of some interest.?
One minor error is the low pass filter corner frequency was 4kHz, not the 10kHz reported on the graphic.

The motor is:

Best regards,

Dick

--

I'd rather have questions that can't be answered than answers that can't be questioned. ? Richard Feynman?
Illegitimi Non Carborundum