Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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Default FOLLOWUP -- Lathe and VFD -- Some results

I wired the VFD to the lathe. Not in the best way yet, but enough to
experiment. Toshiba VF-A3 3.7 kW VFD, similar to what I sold to Pete
C, only bigger and with cracked top cover. (I have more for sale, 2.2
and 3.7 kW)

Here's one very encouraging piece of news (related to what Karl said):
switching of the speed selector lever while the motor is running does
not destroy the drive. It simply trips on a overvoltage error and lets
the lathe coast to stop.

I am very satisfied with this behavior. It is as perfect as it gets.

The drive can easily accelerate the lathe, even at the highest
speed setting, etc.

Right now it trips when I press OFF, no doubt due to too ambitious
braking that is the default setting right now.

What I need to do is:

1) A lot of settings need to be set such as no braking, fixed
frequency (60 Hz), one-two second acceleration, etc etc.

2) Wire it properly to turn on with the limit switch operated by lathe
ON/OFF/BRAKE lever

3) Place the VFD deep inside the lathe cabinet so that it would not be
a hazard or distraction. There is no need to access the drive once it
is set up. So I will put it away. This will be a single phase lathe
that would be operated with its original control and no weird wiring
outside.

The ONLY thing that I may allow to be visible outside is the FAULT
indicator shown by a LED bulb. Maybe a FAULT with RESET
pushbutton. That's all. I do not want switches, potentiometers, none
of that stuff is necessary.

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Default FOLLOWUP -- Lathe and VFD -- Some results

Ignoramus30183 wrote:
I wired the VFD to the lathe. Not in the best way yet, but enough to
experiment. Toshiba VF-A3 3.7 kW VFD, similar to what I sold to Pete
C, only bigger and with cracked top cover. (I have more for sale, 2.2
and 3.7 kW)

Here's one very encouraging piece of news (related to what Karl said):
switching of the speed selector lever while the motor is running does
not destroy the drive. It simply trips on a overvoltage error and lets
the lathe coast to stop.

I am very satisfied with this behavior. It is as perfect as it gets.


Sounds good.

Right now it trips when I press OFF, no doubt due to too ambitious
braking that is the default setting right now.


You probably can set a 1 second rampdown and it won't trip, or put the
braking resistor on.

What I need to do is:


3) Place the VFD deep inside the lathe cabinet so that it would not be
a hazard or distraction. There is no need to access the drive once it
is set up. So I will put it away. This will be a single phase lathe
that would be operated with its original control and no weird wiring
outside.

The ONLY thing that I may allow to be visible outside is the FAULT
indicator shown by a LED bulb. Maybe a FAULT with RESET
pushbutton. That's all. I do not want switches, potentiometers, none
of that stuff is necessary.


Be sure to leave good air circulation, it will generate some heat.

I still need to make a shroud so that there is no direct path for chips
to fly into the unit. My VFD is up above the machine on the headstock end.

Good Luck,
Bob
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Default FOLLOWUP -- Lathe and VFD -- Some results

On 2008-07-17, BobH wrote:
Ignoramus30183 wrote:
I wired the VFD to the lathe. Not in the best way yet, but enough to
experiment. Toshiba VF-A3 3.7 kW VFD, similar to what I sold to Pete
C, only bigger and with cracked top cover. (I have more for sale, 2.2
and 3.7 kW)

Here's one very encouraging piece of news (related to what Karl said):
switching of the speed selector lever while the motor is running does
not destroy the drive. It simply trips on a overvoltage error and lets
the lathe coast to stop.

I am very satisfied with this behavior. It is as perfect as it gets.


Sounds good.

Right now it trips when I press OFF, no doubt due to too ambitious
braking that is the default setting right now.


You probably can set a 1 second rampdown and it won't trip, or put the
braking resistor on.


I will experiment. The issue is, obviously, higher spindle speeds,
requiring longer rampdown.

The other thing I can do is this: the limit switch for tutrning the
lathe on and off, has a normally closed and normally open switch. I
obviously use the N.O switch for RUN. But I can use the N.C. switch
for RESET.

What I need to do is:


3) Place the VFD deep inside the lathe cabinet so that it would not be
a hazard or distraction. There is no need to access the drive once it
is set up. So I will put it away. This will be a single phase lathe
that would be operated with its original control and no weird wiring
outside.

The ONLY thing that I may allow to be visible outside is the FAULT
indicator shown by a LED bulb. Maybe a FAULT with RESET
pushbutton. That's all. I do not want switches, potentiometers, none
of that stuff is necessary.


Be sure to leave good air circulation, it will generate some heat.

I still need to make a shroud so that there is no direct path for chips
to fly into the unit. My VFD is up above the machine on the headstock end.


The base is very big, there is plenty of space, and also the motor is
in the providing some extra circulation. Should be fine.

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to spammers, I and many others block all articles originating
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Default FOLLOWUP -- Lathe and VFD -- Some results


You probably can set a 1 second rampdown and it won't trip, or put the
braking resistor on.


I will experiment. The issue is, obviously, higher spindle speeds,
requiring longer rampdown.


you REALLY DO NOT want a rampdown if you are going to use the mechanical
brake - set it to coast



** Posted from http://www.teranews.com **
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Default FOLLOWUP -- Lathe and VFD -- Some results

On Thu, 17 Jul 2008 18:01:26 -0700, "William Noble"
wrote:


You probably can set a 1 second rampdown and it won't trip, or put the
braking resistor on.


I will experiment. The issue is, obviously, higher spindle speeds,
requiring longer rampdown.


you REALLY DO NOT want a rampdown if you are going to use the mechanical
brake - set it to coast


Correct, else the VFD will be fighting the mechanical brake





** Posted from http://www.teranews.com **



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Default FOLLOWUP -- Lathe and VFD -- Some results

I had some bad news last night.

As the drive was running the motor, the motor leaks a lot of current
through its insulation. (like Joe Gwinn story) Not good. Phase
converter does not create this effect, so it is due to voltage spikes
from the drive that this old insulation cannot handle. I do not want
to ignore this issue by grounding, as I feel that it can ruin the
motor.

I may try to locate a line reactor to dampen this, and shorten some
cables, but for now I will go back to the phase converter.

i
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Default FOLLOWUP -- Lathe and VFD -- Some results


Ignoramus30183 wrote:

I wired the VFD to the lathe. Not in the best way yet, but enough to
experiment. Toshiba VF-A3 3.7 kW VFD, similar to what I sold to Pete
C, only bigger and with cracked top cover. (I have more for sale, 2.2
and 3.7 kW)


The first of those VFDs is doing nicely on my Bridgeport. The second,
along with the 3HP motor from my former RPC is looking like it will end
up replacing the aged 1/2HP motor with failing starting cap on my lathe.
I really need to find a bigger lathe too...
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Default FOLLOWUP -- Lathe and VFD -- Some results

On 2008-07-17, Pete C. wrote:

Ignoramus30183 wrote:

I wired the VFD to the lathe. Not in the best way yet, but enough to
experiment. Toshiba VF-A3 3.7 kW VFD, similar to what I sold to Pete
C, only bigger and with cracked top cover. (I have more for sale, 2.2
and 3.7 kW)


The first of those VFDs is doing nicely on my Bridgeport.


That's very nice to hear. I am delighted.

The second, along with the 3HP motor from my former RPC is looking
like it will end up replacing the aged 1/2HP motor with failing
starting cap on my lathe. I really need to find a bigger lathe
too...


3 HP motor to replace a 1/2 HP motor???

By the way, starting caps cost relatively little.

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
http://improve-usenet.org/
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Default FOLLOWUP -- Lathe and VFD -- Some results


Ignoramus20788 wrote:

On 2008-07-17, Pete C. wrote:

Ignoramus30183 wrote:

I wired the VFD to the lathe. Not in the best way yet, but enough to
experiment. Toshiba VF-A3 3.7 kW VFD, similar to what I sold to Pete
C, only bigger and with cracked top cover. (I have more for sale, 2.2
and 3.7 kW)


The first of those VFDs is doing nicely on my Bridgeport.


That's very nice to hear. I am delighted.

The second, along with the 3HP motor from my former RPC is looking
like it will end up replacing the aged 1/2HP motor with failing
starting cap on my lathe. I really need to find a bigger lathe
too...


3 HP motor to replace a 1/2 HP motor???


Why not? There is room to install it, being a 3ph motor it's pretty
compact, and being on a VFD I can set limits wherever I want.


By the way, starting caps cost relatively little.


Yes, but I'm too lazy to chase after one for a motor I don't care for
anyway.
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Default FOLLOWUP -- Lathe and VFD -- Some results

On 2008-07-17, Pete C. wrote:

Ignoramus20788 wrote:

On 2008-07-17, Pete C. wrote:

Ignoramus30183 wrote:

I wired the VFD to the lathe. Not in the best way yet, but enough to
experiment. Toshiba VF-A3 3.7 kW VFD, similar to what I sold to Pete
C, only bigger and with cracked top cover. (I have more for sale, 2.2
and 3.7 kW)

The first of those VFDs is doing nicely on my Bridgeport.


That's very nice to hear. I am delighted.

The second, along with the 3HP motor from my former RPC is looking
like it will end up replacing the aged 1/2HP motor with failing
starting cap on my lathe. I really need to find a bigger lathe
too...


3 HP motor to replace a 1/2 HP motor???


Why not? There is room to install it, being a 3ph motor it's pretty
compact, and being on a VFD I can set limits wherever I want.


Sounds like fun. I hope that if something gets stuck, the bigger motor
would not break gears or something.

i

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
http://improve-usenet.org/


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Default FOLLOWUP -- Lathe and VFD -- Some results


Ignoramus20788 wrote:

On 2008-07-17, Pete C. wrote:

Ignoramus20788 wrote:

On 2008-07-17, Pete C. wrote:

Ignoramus30183 wrote:

I wired the VFD to the lathe. Not in the best way yet, but enough to
experiment. Toshiba VF-A3 3.7 kW VFD, similar to what I sold to Pete
C, only bigger and with cracked top cover. (I have more for sale, 2.2
and 3.7 kW)

The first of those VFDs is doing nicely on my Bridgeport.

That's very nice to hear. I am delighted.

The second, along with the 3HP motor from my former RPC is looking
like it will end up replacing the aged 1/2HP motor with failing
starting cap on my lathe. I really need to find a bigger lathe
too...

3 HP motor to replace a 1/2 HP motor???


Why not? There is room to install it, being a 3ph motor it's pretty
compact, and being on a VFD I can set limits wherever I want.


Sounds like fun. I hope that if something gets stuck, the bigger motor
would not break gears or something.


Just have to set the current limits appropriately. Also with two stages
of belt drive, a slipping belt is more likely.
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Default FOLLOWUP -- Lathe and VFD -- Some results



Ignoramus30183 wrote:
I wired the VFD to the lathe. Not in the best way yet, but enough to
experiment. Toshiba VF-A3 3.7 kW VFD, similar to what I sold to Pete
C, only bigger and with cracked top cover. (I have more for sale, 2.2
and 3.7 kW)

Here's one very encouraging piece of news (related to what Karl said):
switching of the speed selector lever while the motor is running does
not destroy the drive. It simply trips on a overvoltage error and lets
the lathe coast to stop.

I am very satisfied with this behavior. It is as perfect as it gets.

The drive can easily accelerate the lathe, even at the highest
speed setting, etc.

Right now it trips when I press OFF, no doubt due to too ambitious
braking that is the default setting right now.

What I need to do is:

1) A lot of settings need to be set such as no braking, fixed
frequency (60 Hz), one-two second acceleration, etc etc.

Braking is GOOD, a real safety feature. Even if you have to cobble up a
braking resistor, it is well worth it. I get less than one second stops
on my 15" Sheldon, with a pair of 100 W vitreous enamel resistors wired
up to the braking circuit.

2) Wire it properly to turn on with the limit switch operated by lathe
ON/OFF/BRAKE lever

Yes, that would be really nice. I have the original
forward/reverse/stop buttons on my Sheldon hooked to the VFD,
and it is quite nice. I added a jog button, that is nice for when the
gears don't engage.

Jon

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Default FOLLOWUP -- Lathe and VFD -- Some results

On 2008-07-17, Jon Elson wrote:


Ignoramus30183 wrote:
I wired the VFD to the lathe. Not in the best way yet, but enough to
experiment. Toshiba VF-A3 3.7 kW VFD, similar to what I sold to Pete
C, only bigger and with cracked top cover. (I have more for sale, 2.2
and 3.7 kW)

Here's one very encouraging piece of news (related to what Karl said):
switching of the speed selector lever while the motor is running does
not destroy the drive. It simply trips on a overvoltage error and lets
the lathe coast to stop.

I am very satisfied with this behavior. It is as perfect as it gets.

The drive can easily accelerate the lathe, even at the highest
speed setting, etc.

Right now it trips when I press OFF, no doubt due to too ambitious
braking that is the default setting right now.

What I need to do is:

1) A lot of settings need to be set such as no braking, fixed
frequency (60 Hz), one-two second acceleration, etc etc.

Braking is GOOD, a real safety feature. Even if you have to cobble up a
braking resistor, it is well worth it. I get less than one second stops
on my 15" Sheldon, with a pair of 100 W vitreous enamel resistors wired
up to the braking circuit.


Does your sheldon include a mechanical brake?

Are your 1 second stops, actually happening at high spindle speeds?

My drive already has a braking resistor, IIRC. Some of mine do and
some don't. But even if not. I have some resistors.

2) Wire it properly to turn on with the limit switch operated by lathe
ON/OFF/BRAKE lever

Yes, that would be really nice.


I already did so, it is awesome.

I have the original forward/reverse/stop buttons on my Sheldon
hooked to the VFD, and it is quite nice. I added a jog button, that
is nice for when the gears don't engage.


What is your jog frequency?

Myself, when gears don't engage, I just grab the chuck and rock it a
little.

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
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Default FOLLOWUP -- Lathe and VFD -- Some results



Ignoramus20788 wrote:


Does your sheldon include a mechanical brake?

No! Motor - gearbox - spindle, no clutch, no brake, no varispeed drive.


Are your 1 second stops, actually happening at high spindle speeds?

Yes, the highest nominal speed is 1250 RPM, there is a version of the
lathe with a two-speed motor, but I don't have that. I could take the
motor up to 120 Hz and get 2500 RPM, but the idea of an 8.25" chuck at
2500 RPM scares me!


What is your jog frequency?

I think it is 5 Hz, I don't remember exactly. it is a programmable
parameter.


Myself, when gears don't engage, I just grab the chuck and rock it a
little.


Yes, works fine in high speed mode, but with the backgear engaged, it
takes a lot of force to turn the chuck. I could EASILY live without it,
but since the VFD supported the feature, I put it in, just a push button
and one more wire.

Jon

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