Look what followed me home.

[sc0ch]

Beware, with the VFD you should probably always let the motor run at its rated speed (don't run slower). Unless the motor's insulation class permits, it will probably overheat if run more slowly. Use the gearing to change speed. That's what I've done with my Standard Modern, which lacks a "inverter ready" motor.

 

[MikeInOr]

Beware, with the VFD you should probably always let the motor run at its rated speed (don't run slower). Unless the motor's insulation class permits, it will probably overheat if run more slowly. Use the gearing to change speed. That's what I've done with my Standard Modern, which lacks a "inverter ready" motor.

I have 5 VFD's running various old three phase machines for MANY years now, all with non inverter rated motors (there were NO inverter duty motors when the machines were made). I have never had an issue using the variable speed feature with these old motors. There has been a lot of talk and lore around VFD's and how they will ruin old motors pretty much since the inception of the internet but I have never seen ANY first hand reports of VFD's burning up an old 3 phase motor.

I believe the harmful VFD lore comes from motor manufactures stating their old legacy motors are NOT certified to run on VFD's... why would any motor manufacture accept the liability of stating their old legacy motors are certified running under ANY non-typical configuration (VFD, RPC or static phase converter)? I remember when the lore was VFD's have high frequency spikes that spark through the arbor bearings of old 3 phase motors causing metal erosion resulting in premature bearing failure... this was a very popularly held and often recited belief 20 years ago... the advice of the time was to change the motors to ceramic bearings to prevent this.

My 1960's South Bend 13" lathe is pretty much never running at 60hz. I almost always start running at lower than 60hz and continually bump up the speed (frequency) as the part diameter is reduced which lowers the SFM proportionate to the smaller diameter. The lathe runs fine at 20hz for extended periods of time and is perfectly happy at 120hz. Infinitely variable speeds is an excellent addition to these old lathes, ones that I am not in the least bit afraid to utilize! I greatly value the ability to instantly tune the speed to the cut being made. I.e. if I start getting some chatter I bump the speed until it goes away, something that just can't be done by moving the belt or changing gears mid cut.

Can anyone offer ANY first hand experience where ANY 3 phase motor running on a VFD has failed running at ANY speed?

 

[Dabbler]

Beware, with the VFD you should probably always let the motor run at its rated speed (don't run slower). Unless the motor's insulation class permits, it will probably overheat if run more slowly. Use the gearing to change speed. That's what I've done with my Standard Modern, which lacks a "inverter ready" motor.

I have VFDs running milling machines and surface grinders. I have had no problem going to 30% of rated speed. If I were to go to 10% rated speed, I'd add a computer boxer style fan to run in the same direction as the airflow, cooling the motor. for 10 bucks, you get some insurance (assurance)...

None of my motors are inverter rated.

 

[Janderso]

I picked this up yesterday. Its 3 phase so I will have to get a motor or a single to three phase vfd. I'm super happy to have it. I have sieg clone 9x20 and this standard modern is amazing when it come to quality difference. Ultilathe under standard modern here in Canada. Not sure of the year. says 9inch and in the online lit I can find 22-1/2 inches between centers. It looks to be from the 60's. I could be wrong. Was in a tech shop for more then 10 years maybe used a couple times other then that its in great shape. If anyone can share any info they might have on this lathe. I do have the 20 page manual from the standard modern website. But I have not found much else. View attachment 486456View attachment 486457View attachment 486458

Great find!
Is that a taper attachment? On a 9" lathe??
You found a needle in a haystack with this one.
You kind of suck dude.

 

[DavieJ75]

Great find!
Is that a taper attachment? On a 9" lathe??
You found a needle in a haystack with this one.
You kind of suck dude.

Yes the taper attachment was standard on this lathe. It’s missing some hardware but the slide and the taper parts are all there. Not sure the taper attachment was used much. the Cross slide lead screw is disconnected from an Allen key screw in the cross slide under a flip up cover. So super easy to use the attachment. I am interested to see how the gear selector works with threading. When I saw it I knew I had to have it. These don't come up every day. its A really cool lathe.

 

[Martin W]

Tell us about the Camaro in the background! Is it a 73?
Martin

 

[DavieJ75]

Tell us about the Camaro in the background! Is it a 73?
Martin

I made a new thread in the moves on its own forum

1971 Camaro SS (affectionately called the blue meanie)

I posted some pics of my new standard modern lathe, in the one pic my Camaro is in the back ground and I got some interest in the car. I had been looking for a 71 to 73 since I was a kid. I have had several second gens, a 79, 81. This one is the keeper. Added bonus the wife loves this car and...

www.hobby-machinist.com

 

[DavieJ75]

I want to know about your Camaro there. 71?

Oh the lathe is cool for sure.


Cutting oil is my blood.

I made a separate thread for the Camaro in the moves on its own forum

1971 Camaro SS (affectionately called the blue meanie)

I posted some pics of my new standard modern lathe, in the one pic my Camaro is in the back ground and I got some interest in the car. I had been looking for a 71 to 73 since I was a kid. I have had several second gens, a 79, 81. This one is the keeper. Added bonus the wife loves this car and...

www.hobby-machinist.com