Gentlemen,

I bought a Hitachi SJ200-022NFU2 model, 3 HP VFD to control my "new"
mill, which has a 2HP 3 phase motor.

This model, a "constant torque" VFD, is versatile and sophisticated,
and contains control options far beyond my needs and expertise.

I have carefully and almost completely read the owner's manual. The
basic installation is simple enough. You bring in the 2 legs of 220V
single phase from a 30 amp fuse or breaker, and connect these to
inputs 1 and 3. You ground the mounted VFD and the mill motor in a
star pattern. You connect the appropriate 3 outputs from the VFD to
the motor.

You go through an initial programming sequence, setting up certain
basic parameters. You power up the VFD. You verify certain that
certain pre-conditions are met and that certain LEDs are on or off on
the keypad. You take a deep breath, make the sign of the cross, and
press START.

After that the going gets sort of tough. Here are a couple of things
I don't understand. I will humbly accept your guidance.

First, it is my understanding that it is possibly fatal to the VFD to
switch the motor on or off from the mill's own on-off switch, or to
otherwise control the mill (instant reverse for example) EXCEPT
through the VFD's programmable circuits.

This leads to the following questions:

1) Do I remove the mill's on-off switch completely or otherwise wire
it permanently in the ON position?
2) Do I similarly wire around the wires going to and from the mill's
FORWARD - REVERSE toggle switch and re-route these wires to the VFD's
programmable inputs/outputs?

There was previously some discussion here about whether a VFD can
adequately handle the mill's instant reverse. However, upon careful
reading of the manual the VFD does seem to have a programmable "node"
that allows for this. Apparently this can be tweaked a couple of
ways. One of these involves installing additional resistors. Another
SEEMS to provide for programming the injection of a DC current into
the motor to stop it from coasting. I think these two things are
related but I'm not sure.

I think I can get the thing installed this weekend so that it will at
least start and run. However, my brain is a lot murkier as regards
these programmable controls.

Thanks to one and all.

Vernon

Vernon wrote:
Gentlemen,

I bought a Hitachi SJ200-022NFU2 model, 3 HP VFD to control my "new"
mill, which has a 2HP 3 phase motor.

This model, a "constant torque" VFD, is versatile and sophisticated,
and contains control options far beyond my needs and expertise.

I have carefully and almost completely read the owner's manual. The
basic installation is simple enough. You bring in the 2 legs of 220V
single phase from a 30 amp fuse or breaker, and connect these to
inputs 1 and 3. You ground the mounted VFD and the mill motor in a
star pattern. You connect the appropriate 3 outputs from the VFD to
the motor.

You go through an initial programming sequence, setting up certain
basic parameters. You power up the VFD. You verify certain that
certain pre-conditions are met and that certain LEDs are on or off on
the keypad. You take a deep breath, make the sign of the cross, and
press START.

After that the going gets sort of tough. Here are a couple of things
I don't understand. I will humbly accept your guidance.

First, it is my understanding that it is possibly fatal to the VFD to
switch the motor on or off from the mill's own on-off switch, or to
otherwise control the mill (instant reverse for example) EXCEPT
through the VFD's programmable circuits.

This leads to the following questions:

1) Do I remove the mill's on-off switch completely or otherwise wire
it permanently in the ON position?
2) Do I similarly wire around the wires going to and from the mill's
FORWARD - REVERSE toggle switch and re-route these wires to the VFD's
programmable inputs/outputs?

There was previously some discussion here about whether a VFD can
adequately handle the mill's instant reverse. However, upon careful
reading of the manual the VFD does seem to have a programmable "node"
that allows for this. Apparently this can be tweaked a couple of
ways. One of these involves installing additional resistors. Another
SEEMS to provide for programming the injection of a DC current into
the motor to stop it from coasting. I think these two things are
related but I'm not sure.

I think I can get the thing installed this weekend so that it will at
least start and run. However, my brain is a lot murkier as regards
these programmable controls.

Thanks to one and all.

Vernon

Disclaimer:

I'm an EE, I've driven motors every which way, but I've never bought a
VFD, so I know theory but not particulars.

First:

If you disconnect the mill's on/off switch, put a big red shutoff button
connected to the VFD power out there. Make sure you can reach it when
your tie gets caught in the spindle (you _do_ dress formally when you
use your mill, right?).

Second:

A "constant torque" VFD is going to work, more or less, by figuring out
some of the motor's internal state and driving it's voltages
accordingly. Switching the motor leads is going to confuse the hell out
of it.

Whether or not this damages the VFD is very much a function of whether
the VFD is designed to protect itself. If you're a circuit designer you
can _always_ make a bullet proof circuit. You just can't always get
your product line manager to sign up to it ("don't waste time on that,
our customers won't notice that the thing goes up in smoke the way brand
XYZ doesn't").

Third:

If the thing is well designed, and if it has provisions for reversing
the motor and for dynamic breaking, they'll certainly work better than
using the motor switch. I'd wire them up, and find out if it fits my
definition of "well designed".

Fourth:

Don't forget that emergency stop button. Sharp spinning metal has an
unfortunate effect on flesh.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

On Oct 6, 12:36*pm, Tim Wescott wrote:
Vernon wrote:
Gentlemen,

I bought a Hitachi SJ200-022NFU2 model, 3 HP VFD to control my "new"
mill, which has a 2HP 3 phase motor.

This model, a "constant torque" VFD, is versatile and sophisticated,
and contains control options far beyond my needs and expertise.

I have carefully and almost completely read the owner's manual. *The
basic installation is simple enough. *You bring in the 2 legs of 220V
single phase from a 30 amp fuse or breaker, and connect these to
inputs 1 and 3. *You ground the mounted VFD and the mill motor in a
star pattern. *You connect the appropriate 3 outputs from the VFD to
the motor.

You go through an initial programming sequence, setting up certain
basic parameters. *You power up the VFD. *You verify certain that
certain pre-conditions are met and that certain LEDs are on or off on
the keypad. *You take a deep breath, make the sign of the cross, and
press START.

After that the going gets sort of tough. *Here are a couple of things
I don't understand. *I will humbly accept your guidance.

First, it is my understanding that it is possibly fatal to the VFD to
switch the motor on or off from the mill's own on-off switch, or to
otherwise control the mill (instant reverse for example) EXCEPT
through the VFD's programmable circuits.

This leads to the following questions:

1) Do I remove the mill's on-off switch completely or otherwise wire
it permanently in the ON position?
2) Do I similarly wire around the wires going to and from the mill's
FORWARD - REVERSE toggle switch and re-route these wires to the VFD's
programmable inputs/outputs?

There was previously some discussion here about whether a VFD can
adequately handle the mill's instant reverse. *However, upon careful
reading of the manual the VFD does seem to have a programmable "node"
that allows for this. *Apparently this can be tweaked a couple of
ways. *One of these involves installing additional resistors. *Another
SEEMS to provide for programming the injection of a DC current into
the motor to stop it from coasting. *I think these two things are
related but I'm not sure.

I think I can get the thing installed this weekend so that it will at
least start and run. *However, my brain is a lot murkier as regards
these programmable controls.

Thanks to one and all.

Vernon

Disclaimer:

I'm an EE, I've driven motors every which way, but I've never bought a
VFD, so I know theory but not particulars.

First:

If you disconnect the mill's on/off switch, put a big red shutoff button
connected to the VFD power out there. *Make sure you can reach it when
your tie gets caught in the spindle (you _do_ dress formally when you
use your mill, right?).

Second:

A "constant torque" VFD is going to work, more or less, by figuring out
some of the motor's internal state and driving it's voltages
accordingly. *Switching the motor leads is going to confuse the hell out
of it.

Whether or not this damages the VFD is very much a function of whether
the VFD is designed to protect itself. *If you're a circuit designer you
can _always_ make a bullet proof circuit. *You just can't always get
your product line manager to sign up to it ("don't waste time on that,
our customers won't notice that the thing goes up in smoke the way brand
XYZ doesn't").

Third:

If the thing is well designed, and if it has provisions for reversing
the motor and for dynamic breaking, they'll certainly work better than
using the motor switch. *I'd wire them up, and find out if it fits my
definition of "well designed".

Fourth:

Don't forget that emergency stop button. *Sharp spinning metal has an
unfortunate effect on flesh.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says..
See details athttp://www.wescottdesign.com/actfes/actfes.html- Hide quoted text -

- Show quoted text -

Tim. On behalf of my tender flesh I thank you! V

Tim Wescott writes:

Vernon wrote:

Disclaimer:

I'm an EE, I've driven motors every which way, but I've never bought a
VFD, so I know theory but not particulars.

Meetoo..

First:

If you disconnect the mill's on/off switch, put a big red shutoff button
connected to the VFD power out there. Make sure you can reach it when
your tie gets caught in the spindle (you _do_ dress formally when you
use your mill, right?).

Second:

See First: It's the most important aspect.

Depending on the VFD, maybe it has a shutdown function, but don't depend
on it. I'd have a direct 3-phase pushbutton, the latching kind. [Push in,
it stays in until unlatched.] Use an aux contact for the VFD.


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Oct 6, 1:10*pm, David Lesher wrote:
Tim Wescott writes:
Vernon wrote:
Disclaimer:
I'm an EE, I've driven motors every which way, but I've never bought a
VFD, so I know theory but not particulars.

Meetoo..

First:
If you disconnect the mill's on/off switch, put a big red shutoff button
connected to the VFD power out there. *Make sure you can reach it when
your tie gets caught in the spindle (you _do_ dress formally when you
use your mill, right?).

Second:

See First: It's the most important aspect.

Depending on the VFD, maybe it has a shutdown function, but don't depend
on it. I'd have a direct 3-phase pushbutton, the latching kind. [Push in,
it stays in until unlatched.] Use an aux contact for the VFD.

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Dave,

"Depending on the VFD, maybe it has a shutdown function, but don't
depend
on it. I'd have a direct 3-phase pushbutton, the latching kind. [Push
in,
it stays in until unlatched.] Use an aux contact for the VFD."

I did not understand this. The VFD manual says to have a disconnect
device but not to use it except in an emergency. Obviously, getting
entwined in rotating machinery is an emergency and trumps trashing the
VFD.

I will try to get a picture of the controls on the mill and publish
this. Hopefully y'all will take a look.

Thanks! Vernon

On Mon, 6 Oct 2008 10:08:56 -0700 (PDT), Vernon
wrote:


1) Do I remove the mill's on-off switch completely or otherwise wire
it permanently in the ON position?

If this is simply a switch in the incoming line, use it to feed power
to the VFD.

2) Do I similarly wire around the wires going to and from the mill's
FORWARD - REVERSE toggle switch and re-route these wires to the VFD's
programmable inputs/outputs?

Yes, though I prefer three pushbuttons -- FWD/OFF/REV.

Plan on setting up a pot for speed adjustment. If you use the drive's
keypad for speed changes you'll lose much of the convenience the drive
offers.


There was previously some discussion here about whether a VFD can
adequately handle the mill's instant reverse. However, upon careful
reading of the manual the VFD does seem to have a programmable "node"
that allows for this. Apparently this can be tweaked a couple of
ways. One of these involves installing additional resistors. Another
SEEMS to provide for programming the injection of a DC current into
the motor to stop it from coasting. I think these two things are
related but I'm not sure.

You'll have to experiment to see what works for you. On many drives
the accel and decel settings are set in seconds even though the actual
effect is "seconds per 60 Hz." The result is that at low speed
settings the reverse is very quick. The most obvious application is
for power tapping, where it's often convenient to drill at high speed,
then turn the speed down to tap, and reverse to back the tap out. If
your drive is one that behaves as I've described above, the tap
reversal will be almost instantaneous at 10 Hz with, say, a 1 second
(at 60 Hz) accel/decel setting. If your drive's manual is silent or
vague on this point, you'll have to experiment to determine its actual
behavior.


I think I can get the thing installed this weekend so that it will at
least start and run. However, my brain is a lot murkier as regards
these programmable controls.

Thanks to one and all.

Vernon

This is a block diagram of how I'd recommend you wire you mill. (View
with a fixed pitch font.)

(Line In) - (Main Power Switch) - ( VFD ) - (Motor)
^ ^
| |
(FWD/OFF/REV) (Speed Pot)

Here's photo of that setup on my mill:
http://www.suscom-maine.net/~nsimmons/news/MillVFD.JPG

--
Ned Simmons

Vernon wrote:
On Oct 6, 1:10 pm, David Lesher wrote:
Tim Wescott writes:
Vernon wrote:
Disclaimer:
I'm an EE, I've driven motors every which way, but I've never bought a
VFD, so I know theory but not particulars.
Meetoo..

First:
If you disconnect the mill's on/off switch, put a big red shutoff button
connected to the VFD power out there. Make sure you can reach it when
your tie gets caught in the spindle (you _do_ dress formally when you
use your mill, right?).
Second:

See First: It's the most important aspect.

Depending on the VFD, maybe it has a shutdown function, but don't depend
on it. I'd have a direct 3-phase pushbutton, the latching kind. [Push in,
it stays in until unlatched.] Use an aux contact for the VFD.

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Dave,

"Depending on the VFD, maybe it has a shutdown function, but don't
depend
on it. I'd have a direct 3-phase pushbutton, the latching kind. [Push
in,
it stays in until unlatched.] Use an aux contact for the VFD."

I did not understand this. The VFD manual says to have a disconnect
device but not to use it except in an emergency. Obviously, getting
entwined in rotating machinery is an emergency and trumps trashing the
VFD.

I will try to get a picture of the controls on the mill and publish
this. Hopefully y'all will take a look.


There are bazillions of things that can go wrong inside of an electronic
device that'll make it 'stick on'. Unless your VFD has been
specifically engineered so that you can trust your life to its built-in
shutdown, use an external shutdown.

Here's a test to see if the VFDs built-in shutdown is life-rated.
Answer each of the below questions "yes" or "no", then score the
indicated number of points for each "yes" answer, no points for "no".
Add up the point scores of every question. If the score is greater than
99, then you can trust the VFD with your life. Otherwise, use an
external shut down.

Does the VFD cost as much as a new Cessna? (100 points).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

On my mill, I have 220v single phase coming in, going through a VFD,
then a FWD-OFF-REV switch, and into the motor.

I do not use the reversing switch to turn or reverse the motor. I use
the VFD for it.

What I do use the motor is to make the motor go in the right direction
when switching in and out of backgear. If I switch to a slow speed via
backgear, then all things being kept the same, the spind would turn
backwards when I turn VFD into FWD. That's stupid. So, I maDE A RULE
for myself, whenever I switch the mill to/from the backgear, I flip
the FWD/REV switch on the mill to keep FWD rotation the same. Works
for me.

I use the VFD for plug reversing.

i

Vernon writes:

"Depending on the VFD, maybe it has a shutdown function, but don't
depend on it. I'd have a direct 3-phase pushbutton, the latching
kind. [Push in, it stays in until unlatched.] Use an aux contact for the
VFD."

I did not understand this. The VFD manual says to have a disconnect
device but not to use it except in an emergency. Obviously, getting
entwined in rotating machinery is an emergency and trumps trashing the
VFD.


Get a pushbutton, a big industrial one. Allen Bradley comes to mind. They
are basically Legos; you start with the basic button and add contacts of
the type needed.

It should have 3 contacts rated for the full current of the motor. They
will be closed in OUT mode, but open when pushed in. Wire in series
with all three legs going to the motor..

Have a low current 4th contact going to the VFD shutdown connection.

This will break the power feed to your mill when hit, AND send a shutdown
to the VFD. [It may take a while to turn off, however, as compared to the
button. Maybe even as much a second or two; see what the VFD Fine Manual
says.]

This way, even if the shutdown command does not work, the power *is* off.

The shutdown pushbutton will be expensive new. There are millions surplus
but it will be tricky to mail-order same. If you have a surplus place
nearby....

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

David Lesher wrote:

Vernon writes:

"Depending on the VFD, maybe it has a shutdown function, but don't
depend on it. I'd have a direct 3-phase pushbutton, the latching
kind. [Push in, it stays in until unlatched.] Use an aux contact for the
VFD."

I did not understand this. The VFD manual says to have a disconnect
device but not to use it except in an emergency. Obviously, getting
entwined in rotating machinery is an emergency and trumps trashing the
VFD.

Get a pushbutton, a big industrial one. Allen Bradley comes to mind. They
are basically Legos; you start with the basic button and add contacts of
the type needed.

It should have 3 contacts rated for the full current of the motor. They
will be closed in OUT mode, but open when pushed in. Wire in series
with all three legs going to the motor..

Have a low current 4th contact going to the VFD shutdown connection.

This will break the power feed to your mill when hit, AND send a shutdown
to the VFD. [It may take a while to turn off, however, as compared to the
button. Maybe even as much a second or two; see what the VFD Fine Manual
says.]

This way, even if the shutdown command does not work, the power *is* off.

The shutdown pushbutton will be expensive new. There are millions surplus
but it will be tricky to mail-order same. If you have a surplus place
nearby....

The E-stop switch belongs on the power feed *to* the VFD, *not* on the
motor leads from the VFD, otherwise you just have a "VFD destruct"
button. The diagrams in the VFD manual should show the proper wiring for
an emergency stop.

Tim Wescott writes:


There are bazillions of things that can go wrong inside of an electronic
device that'll make it 'stick on'. Unless your VFD has been
specifically engineered so that you can trust your life to its built-in
shutdown, use an external shutdown.

Better than my wording. except I'd say "external emergency shutdown"
to be explicit. No reason not to have other ones.

Here's another case: A mag-locked exit door, with an EXIT button
adjacent. Every code I have seen requires that to be a NC pushbutton, in
series with the lock. Push it, the lock has no power, period. You escape
the fire.

Another example of safety design: it's considered bad form to have a
microwave oven running with the door open. So it has two sets of door
switches that, if either opens, the oven is off.

PLUS, there's a third switch that CLOSES when the door is open. If
somehow, power IS still on, its contacts short out the power and smoke
something [fuse/breaker/etc.]

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

I use/install vfds almost every day.

Most have a STOP input or even an Estop input

Ive never seen one fail before. Ever

Hitting the Stop button generally makes sure the drive shuts the
spindle etc etc virtually instantly.

Turning off the power insures the spindle etc coasts to a stop.

Are you sure that you want to have the lathe spindle coast to a stop
when its got your tie in a chuck jaw?

Just thought Id mention that ........

Gunner

Whenever a Liberal utters the term "Common Sense approach"....grab your
wallet, your ass, and your guns because the sombitch is about to do
something damned nasty to all three of them.

On Oct 6, 8:39*pm, Gunner Asch wrote:
I use/install vfds almost every day.

Most have a STOP input or even an Estop input

Ive never seen one fail before. Ever

Hitting the Stop button generally makes sure the drive shuts the
spindle etc etc virtually instantly.

Turning off the power insures the spindle etc coasts to a stop.

Are you sure that you want to have the lathe spindle coast to a stop
when its got your tie in a chuck jaw?

Just thought Id mention that ........

Gunner

*Whenever a Liberal utters the term "Common Sense approach"....grab your
*wallet, your ass, and your guns because the sombitch is about to do
*something damned nasty to all three of them.

Gunner. Thanks for your valuable input. I would be more than happy
to feed ALL my ties into the lathe spindle provided my neck ain't in
'em!

I am continuing to soak up the manual along with everybody's
collective input. I intend to proceed to do the installation and the
basic start-up test and then stop at the threshold of all the stuff I
still don't understand. No doubt I will have many more questions
soon. Hopefully, they will be more specific and intelligently
articulated.

Thanks to all.

V

On Mon, 06 Oct 2008 14:46:50 -0500, "Pete C." wrote:
David Lesher wrote:
Vernon writes:

"Depending on the VFD, maybe it has a shutdown function, but don't
depend on it. I'd have a direct 3-phase pushbutton, the latching
kind. [Push in, it stays in until unlatched.] Use an aux contact for the
VFD."

I did not understand this. The VFD manual says to have a disconnect
device but not to use it except in an emergency. Obviously, getting
entwined in rotating machinery is an emergency and trumps trashing the
VFD.

Get a pushbutton, a big industrial one. Allen Bradley comes to mind. They
are basically Legos; you start with the basic button and add contacts of
the type needed.

It should have 3 contacts rated for the full current of the motor. They
will be closed in OUT mode, but open when pushed in. Wire in series
with all three legs going to the motor..

Have a low current 4th contact going to the VFD shutdown connection.

This will break the power feed to your mill when hit, AND send a shutdown
to the VFD. [It may take a while to turn off, however, as compared to the
button. Maybe even as much a second or two; see what the VFD Fine Manual
says.]

This way, even if the shutdown command does not work, the power *is* off.

The shutdown pushbutton will be expensive new. There are millions surplus
but it will be tricky to mail-order same. If you have a surplus place
nearby....

The E-stop switch belongs on the power feed *to* the VFD, *not* on the
motor leads from the VFD, otherwise you just have a "VFD destruct"
button. The diagrams in the VFD manual should show the proper wiring for
an emergency stop.

The proper way to rig a Panic Button (Emergency Cutoff) IMHO is with
a motor starter type dedicated purpose contactor sized for the motor
current, wired into the power feed to the tool before the VFD. Get
real contactor with internal magnetic arc chutes (not just a relay) to
make sure it can interrupt heavy loads, you can draw a pretty good arc
at 240V and really nice ones at 480V.

You do NOT want to open the line between the VFD and the motor,
period - the odds of smoking the VFD are rather high. If you want to
wire the factory switches to something, hook it to the remote start
and remoter stop leads of the VFD.

Put your ECO Panic Button near the operating position with a classic
Big Red Mushroom Head operator, and if this is a large tool where you
might get in trouble while standing on the back side out of range of
the main controls, put a separate ECO back there, too. The switches
are Normally Closed loop wired, so any switch breaks the power to the
contactor coil and shuts it down.

Big equipment like web-fed color newspaper printing presses can have
dozens of ECO switches scattered all over, they place them wherever
someone might have to go make an adjustment exposed to moving parts
with the press running. You always want one within easy reach.

And if you want to get fancy, you can rig Safety Shutdowns into that
ECO loop. For instance you can rig a microswitch or two for a contact
shutdown if the stock in an automatic swiss screw lathe bar feeder
bends and start whipping. They can do a LOT of damage before you get
there to slap the button.

-- Bruce --

On 2008-10-06, Vernon wrote:
Gentlemen,

I bought a Hitachi SJ200-022NFU2 model, 3 HP VFD to control my "new"
mill, which has a 2HP 3 phase motor.

This model, a "constant torque" VFD, is versatile and sophisticated,
and contains control options far beyond my needs and expertise.

Sounds like a good choice. The 3HP rating of the VFD should
provide sufficient derating when running a 2HP motor.

I have carefully and almost completely read the owner's manual. The
basic installation is simple enough. You bring in the 2 legs of 220V
single phase from a 30 amp fuse or breaker, and connect these to
inputs 1 and 3.

Some have a jumper between input 2 and one of the others, but
yours is probably newer than mine, which was one of the previous batch
which were being sold off cheap to make room for the newer ones such as
what you have.

You ground the mounted VFD and the mill motor in a
star pattern.

Actually -- you only ground the motor's *case* or frame, not the
center tap of the motor's windings. I would be tempted to call it a Wye
(Y) instead of a star, since it is only three phase, though the other
term can apply as well.

*But* -- a Bridgeport three-phase motor is dual voltage, and you
will be using it wired for 240V, not 480V. Wired that way, there is a
Wye which has the common point buried inside the motor, and you make a
second Wye by joining (and insulating) the proper ends of the other
wires, and the outside ends get connected in parallel with the first
Wye. Thus you can't really get to the center point of the primary Wye,
without tearing the motor apart and probably voiding whatever warranty
is still present. The Wye (or you could run a Delta if the motor were
designed for it) can totally float. The ground to the frame makes the
safety ground you need.

You connect the appropriate 3 outputs from the VFD to
the motor.

Yes.

You go through an initial programming sequence, setting up certain
basic parameters. You power up the VFD. You verify certain that
certain pre-conditions are met and that certain LEDs are on or off on
the keypad. You take a deep breath, make the sign of the cross, and
press START.

:-)

After that the going gets sort of tough. Here are a couple of things
I don't understand. I will humbly accept your guidance.

First, it is my understanding that it is possibly fatal to the VFD to
switch the motor on or off from the mill's own on-off switch, or to
otherwise control the mill (instant reverse for example) EXCEPT
through the VFD's programmable circuits.

This is generally correct. The exception can be found when the
rating of the VFD is sufficiently larger than the motor's rating, and
there is as sufficient length of cable to act as capacitive bypass. As
an example -- my Nichols horizontal mill (1HP motor) is across the shop
from the 7.5 HP VFD -- too far to easily run the control wires, but I
can get away with switching it at the mill end of the cable, and even
with plug reversing.

But for any reasonable rating match, you should not do this,
especially if the machine and motor are close to the VFD.

This leads to the following questions:

1) Do I remove the mill's on-off switch completely or otherwise wire
it permanently in the ON position?

No -- you wire directly from the mill's motor to the VFD --
skipping the on-off switch and the forward-reverse switch. (Note that
some machines, such as the BOSS-3 CNC version of the Bridgeport Series-1
have a buried reversing relay (a double contactor interlocked so only
one direction can be energized at a time). Anyway -- with the wire
going directly from the motor to the VFD, you will have bypassed this as
well -- if it exists.

Now -- rip out the wiring on the on/off switch and the
forward/reverse switch. (Are they not all one switch on your machine --
forward/stop/reverse?) and run the switch contacts into the VFD's
command terminals, so your original switches tell the VFD to start the
motor and in which direction. It is best to use shielded wire for this,
with the shield connected to the ground on the control logic terminals,
since electrical noise spikes could otherwise be picked up by the wires
and perhaps produce undesired activity on the motor.

You probably also want to add another small box under the
direction switch to hold a potentiometer to allow varying the speed
between whatever you have programmed as "full speed" and a dead stop.

Don't run the motor very slow for long, because you will lose
the cooling from the internal fan on the motor's shaft.

2) Do I similarly wire around the wires going to and from the mill's
FORWARD - REVERSE toggle switch and re-route these wires to the VFD's
programmable inputs/outputs?

Direct from motor to the VFD -- skipping all switches on the
machine.

Then wire the switches to tell the VFD what you want it to do.
Note that using the original switches in the original positions will
keep you reaching for the right controls, so if you are ever in a
position to use someone else's machine, your habits will be right in
case you need to stop it in a hurry.

There was previously some discussion here about whether a VFD can
adequately handle the mill's instant reverse. However, upon careful
reading of the manual the VFD does seem to have a programmable "node"
that allows for this. Apparently this can be tweaked a couple of
ways. One of these involves installing additional resistors. Another
SEEMS to provide for programming the injection of a DC current into
the motor to stop it from coasting. I think these two things are
related but I'm not sure.

Two ways to the same end.

The resistor is to absorb power generated by the spinning motor
to slow it down more quickly.

The DC through the motor will stop it more quickly.

As soon as the motor reaches a stop, the VFD can automatically
accelerate it to the desired speed in the other direction.

I think I can get the thing installed this weekend so that it will at
least start and run. However, my brain is a lot murkier as regards
these programmable controls.

Play with them for a while (perhaps just connected to the motor
with no mill cutting taking place) -- learn what they do -- and then
leave them set to whatever works best. The only controls you really
need are within reach on the machine -- the forward/stop/reverse switch
and the speed control pot.

Another thing which you may or may not know -- depending on
whether you have used other Bridgeports. When you engage the back-gear
with the lever on the right hand side of the head, the spindle direction
will reverse. It might be worth while adding a switch in a chip-proof
housing to sense the position of the lever to reverse what your forward
and reverse switch does. (Of course, this is the reverse of what I was
saying above to keep the action of the switches standard. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Oct 7, 10:24*pm, "DoN. Nichols" wrote:
On 2008-10-06, Vernon wrote:

Gentlemen,

I bought a Hitachi SJ200-022NFU2 model, 3 HP VFD to control my "new"
mill, which has a 2HP 3 phase motor.

This model, a "constant torque" VFD, is versatile and sophisticated,
and contains control options far beyond my needs and expertise.

* * * * Sounds like a good choice. *The 3HP rating of the VFD should
provide sufficient derating when running a 2HP motor.

I have carefully and almost completely read the owner's manual. *The
basic installation is simple enough. *You bring in the 2 legs of 220V
single phase from a 30 amp fuse or breaker, and connect these to
inputs 1 and 3.

* * * * Some have a jumper between input 2 and one of the others, but
yours is probably newer than mine, which was one of the previous batch
which were being sold off cheap to make room for the newer ones such as
what you have.

* * * * * * * * *You ground the mounted VFD and the mill motor in a
star pattern.

* * * * Actually -- you only ground the motor's *case* or frame, not the
center tap of the motor's windings. *I would be tempted to call it a Wye
(Y) instead of a star, since it is only three phase, though the other
term can apply as well.

* * * * *But* -- a Bridgeport three-phase motor is dual voltage, and you
will be using it wired for 240V, not 480V. *Wired that way, there is a
Wye which has the common point buried inside the motor, and you make a
second Wye by joining (and insulating) the proper ends of the other
wires, and the outside ends get connected in parallel with the first
Wye. *Thus you can't really get to the center point of the primary Wye,
without tearing the motor apart and probably voiding whatever warranty
is still present. *The Wye (or you could run a Delta if the motor were
designed for it) can totally float. *The ground to the frame makes the
safety ground you need.

* * * * * * * *You connect the appropriate 3 outputs from the VFD to
the motor.

* * * * Yes.

You go through an initial programming sequence, setting up certain
basic parameters. *You power up the VFD. *You verify certain that
certain pre-conditions are met and that certain LEDs are on or off on
the keypad. *You take a deep breath, make the sign of the cross, and
press START.

* * * * :-)

After that the going gets sort of tough. *Here are a couple of things
I don't understand. *I will humbly accept your guidance.

First, it is my understanding that it is possibly fatal to the VFD to
switch the motor on or off from the mill's own on-off switch, or to
otherwise control the mill (instant reverse for example) EXCEPT
through the VFD's programmable circuits.

* * * * This is generally correct. *The exception can be found when the
rating of the VFD is sufficiently larger than the motor's rating, and
there is as sufficient length of cable to act as capacitive bypass. *As
an example -- my Nichols horizontal mill (1HP motor) is across the shop
from the 7.5 HP VFD -- too far to easily run the control wires, but I
can get away with switching it at the mill end of the cable, and even
with plug reversing.

* * * * But for any reasonable rating match, you should not do this,
especially if the machine and motor are close to the VFD.

This leads to the following questions:

1) Do I remove the mill's on-off switch completely or otherwise wire
it permanently in the ON position?

* * * * No -- you wire directly from the mill's motor to the VFD --
skipping the on-off switch and the forward-reverse switch. *(Note that
some machines, such as the BOSS-3 CNC version of the Bridgeport Series-1
have a buried reversing relay (a double contactor interlocked so only
one direction can be energized at a time). *Anyway -- with the wire
going directly from the motor to the VFD, you will have bypassed this as
well -- if it exists.

* * * * Now -- rip out the wiring on the on/off switch and the
forward/reverse switch. *(Are they not all one switch on your machine --
forward/stop/reverse?) and run the switch contacts into the VFD's
command terminals, so your original switches tell the VFD to start the
motor and in which direction. *It is best to use shielded wire for this,
with the shield connected to the ground on the control logic terminals,
since electrical noise spikes could otherwise be picked up by the wires
and perhaps produce undesired activity on the motor.

* * * * You probably also want to add another small box under the
direction switch to hold a potentiometer to allow varying the speed
between whatever you have programmed as "full speed" and a dead stop.

* * * * Don't run the motor very slow for long, because you will lose
the cooling from the internal fan on the motor's shaft.

2) Do I similarly wire around the wires going to and from the mill's
FORWARD - REVERSE toggle switch and re-route these wires to the VFD's
programmable inputs/outputs?

* * * * Direct from motor to the VFD -- skipping all switches on the
machine.

* * * * Then wire the switches to tell the VFD what you want it to do.
Note that using the original switches in the original positions will
keep you reaching for the right controls, so if you are ever in a
position to use someone else's machine, your habits will be right in
case you need to stop it in a hurry.

There was previously some discussion here about whether a VFD can
adequately handle the mill's instant reverse. *However, upon careful
reading of the manual the VFD does seem to have a programmable "node"
that allows for this. *Apparently this can be tweaked a couple of
ways. *One of these involves installing additional resistors. *Another
SEEMS to provide for programming the injection of a DC current into
the motor to stop it from coasting. *I think these two things are
related but I'm not sure.

* * * * Two ways to the same end.

* * * * The resistor is to absorb power generated by the spinning motor
to slow it down more quickly.

* * * * The DC through the motor will stop it more quickly.

* * * * As soon as the motor reaches a stop, the VFD can automatically
accelerate it to the desired speed in the other direction.

I think I can get the thing installed this weekend so that it will at
least start and run. *However, my brain is a lot murkier as regards
these programmable controls.

* * * * Play with them for a while (perhaps just connected to the motor
with no mill cutting taking place) -- learn what they do -- and then
leave them set to whatever works best. *The only controls you really
need are within reach on the machine -- the forward/stop/reverse switch
and the speed control pot.

* * * * Another thing which you may or may not know -- depending on
whether you have used other Bridgeports. *When you engage the back-gear
with the lever on the right hand side of the head, the spindle direction
will reverse. *It might be worth while adding a switch in a chip-proof
housing to sense the position of the lever to reverse what your forward
and reverse switch does. *(Of course, this is the reverse of what I was
saying above to keep the action of the switches standard. :-)

* * * * Enjoy,
* * * * * * * * DoN.

--
*Email: * * | Voice (all times): (703) 938-4564
* * * * (too) near Washington D.C. |http://www.d-and-d.com/dnichols/DoN.html
* * * * * *--- Black Holes are where God is dividing by zero ---

Don. That was very very helpful. However, I bitterly regret to
inform you that my mill is not a Bridgeport. It is a common garden
variety Taiwanese bench mill. It's like a drill press on steroids.
Ironically, I bought it for two reasons: First, there were no
bidders. Second, I mistakenly thought that it was single phase and
that this would be the biggest thing to be had that WOULD operate on
single phase.

Too late, I discovered that it was 3 phase. Thus, I had to pop down
this VFD rabbit hole. Had I know in advance how wunnerful and
versatile they are, I coulda/ shoulda bought a full sized mill. But
time ain't over for me yet. So maybe there's another mill in my
future.

Best. Vernon

On 2008-10-06, Pete C. wrote:

David Lesher wrote:

[ ... ]

Get a pushbutton, a big industrial one. Allen Bradley comes to mind. They
are basically Legos; you start with the basic button and add contacts of
the type needed.

It should have 3 contacts rated for the full current of the motor. They
will be closed in OUT mode, but open when pushed in. Wire in series
with all three legs going to the motor..

Have a low current 4th contact going to the VFD shutdown connection.

This will break the power feed to your mill when hit, AND send a shutdown
to the VFD. [It may take a while to turn off, however, as compared to the
button. Maybe even as much a second or two; see what the VFD Fine Manual
says.]

This way, even if the shutdown command does not work, the power *is* off.

The shutdown pushbutton will be expensive new. There are millions surplus
but it will be tricky to mail-order same. If you have a surplus place
nearby....

The E-stop switch belongs on the power feed *to* the VFD, *not* on the
motor leads from the VFD, otherwise you just have a "VFD destruct"
button. The diagrams in the VFD manual should show the proper wiring for
an emergency stop.

Except that the VFD has a set of big capacitors in there, which
could keep it running for a second or so after the power line is cut.

As long as this is only to be used in a true emergency, what I
would do is set it up to drop power to the VFD (two NC contacts), and to
*short* the power from the VFD to the motor (three NO contacts) so not
only will the power be removed from the motor, but you will also have
regenerative braking.

This is likely to not damage the VFD -- because they have
circuitry to sense excess current and to shut themselves down under
those conditions -- but it is not *certain* that it would survive this.
More likely than with the high voltage spikes from opening the circuit
to the motor windings which can fry the output transistors.

Remember that it is truly an *emergency* stop button only. When
life and limb are in danger, is the time to hit this -- not just when
you want to walk away from the machine for a while.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"DoN. Nichols" wrote:

On 2008-10-06, Pete C. wrote:

David Lesher wrote:

[ ... ]

Get a pushbutton, a big industrial one. Allen Bradley comes to mind. They
are basically Legos; you start with the basic button and add contacts of
the type needed.

It should have 3 contacts rated for the full current of the motor. They
will be closed in OUT mode, but open when pushed in. Wire in series
with all three legs going to the motor..

Have a low current 4th contact going to the VFD shutdown connection.

This will break the power feed to your mill when hit, AND send a shutdown
to the VFD. [It may take a while to turn off, however, as compared to the
button. Maybe even as much a second or two; see what the VFD Fine Manual
says.]

This way, even if the shutdown command does not work, the power *is* off.

The shutdown pushbutton will be expensive new. There are millions surplus
but it will be tricky to mail-order same. If you have a surplus place
nearby....

The E-stop switch belongs on the power feed *to* the VFD, *not* on the
motor leads from the VFD, otherwise you just have a "VFD destruct"
button. The diagrams in the VFD manual should show the proper wiring for
an emergency stop.

Except that the VFD has a set of big capacitors in there, which
could keep it running for a second or so after the power line is cut.

While they'll keep the VFD controls running for a second or two, they
most certainly will not power the motor for any length of time.


As long as this is only to be used in a true emergency, what I
would do is set it up to drop power to the VFD (two NC contacts), and to
*short* the power from the VFD to the motor (three NO contacts) so not
only will the power be removed from the motor, but you will also have
regenerative braking.

Cutting power to the VFD and triggering the VFD's e-stop input should
allow it to do some braking during the second or two it's caps keep the
control operating.


This is likely to not damage the VFD -- because they have
circuitry to sense excess current and to shut themselves down under
those conditions -- but it is not *certain* that it would survive this.
More likely than with the high voltage spikes from opening the circuit
to the motor windings which can fry the output transistors.

Remember that it is truly an *emergency* stop button only. When
life and limb are in danger, is the time to hit this -- not just when
you want to walk away from the machine for a while.

The best course is to follow the e-stop wiring guides provided in the
VFD manual.

On Oct 8, 10:02*am, "Pete C." wrote:
"DoN. Nichols" wrote:

On 2008-10-06, Pete C. wrote:

David Lesher wrote:

* * * * [ ... ]

Get a pushbutton, a big industrial one. Allen Bradley comes to mind. They
are basically Legos; you start with the basic button and add contacts of
the type needed.

It should have 3 contacts rated for the full current of the motor. They
will be closed in OUT mode, but open when pushed in. Wire in series
with all three legs going to the motor..

Have a low current 4th contact going to the VFD shutdown connection.

This will break the power feed to your mill when hit, AND send a shutdown
to the VFD. [It may take a while to turn off, however, as compared to the
button. Maybe even as much a second or two; see what the VFD Fine Manual
says.]

This way, even if the shutdown command does not work, the power *is* off.

The shutdown pushbutton will be expensive new. There are millions surplus
but it will be tricky to mail-order same. If you have a surplus place
nearby....

The E-stop switch belongs on the power feed *to* the VFD, *not* on the
motor leads from the VFD, otherwise you just have a "VFD destruct"
button. The diagrams in the VFD manual should show the proper wiring for
an emergency stop.

* * * * Except that the VFD has a set of big capacitors in there, which
could keep it running for a second or so after the power line is cut.

While they'll keep the VFD controls running for a second or two, they
most certainly will not power the motor for any length of time.



* * * * As long as this is only to be used in a true emergency, what I
would do is set it up to drop power to the VFD (two NC contacts), and to
*short* the power from the VFD to the motor (three NO contacts) so not
only will the power be removed from the motor, but you will also have
regenerative braking.

Cutting power to the VFD and triggering the VFD's e-stop input should
allow it to do some braking during the second or two it's caps keep the
control operating.



* * * * This is likely to not damage the VFD -- because they have
circuitry to sense excess current and to shut themselves down under
those conditions -- but it is not *certain* that it would survive this.
More likely than with the high voltage spikes from opening the circuit
to the motor windings which can fry the output transistors.

* * * * Remember that it is truly an *emergency* stop button only. *When
life and limb are in danger, is the time to hit this -- not just when
you want to walk away from the machine for a while.

The best course is to follow the e-stop wiring guides provided in the
VFD manual.- Hide quoted text -

- Show quoted text -

Thanks. But is "e-stop" the same as "dynamic braking"? The latter
term is the only thing I see in the glossary.

V

On Oct 8, 10:02*am, "Pete C." wrote:
"DoN. Nichols" wrote:

On 2008-10-06, Pete C. wrote:

David Lesher wrote:

* * * * [ ... ]

Get a pushbutton, a big industrial one. Allen Bradley comes to mind. They
are basically Legos; you start with the basic button and add contacts of
the type needed.

It should have 3 contacts rated for the full current of the motor. They
will be closed in OUT mode, but open when pushed in. Wire in series
with all three legs going to the motor..

Have a low current 4th contact going to the VFD shutdown connection.

This will break the power feed to your mill when hit, AND send a shutdown
to the VFD. [It may take a while to turn off, however, as compared to the
button. Maybe even as much a second or two; see what the VFD Fine Manual
says.]

This way, even if the shutdown command does not work, the power *is* off.

The shutdown pushbutton will be expensive new. There are millions surplus
but it will be tricky to mail-order same. If you have a surplus place
nearby....

The E-stop switch belongs on the power feed *to* the VFD, *not* on the
motor leads from the VFD, otherwise you just have a "VFD destruct"
button. The diagrams in the VFD manual should show the proper wiring for
an emergency stop.

* * * * Except that the VFD has a set of big capacitors in there, which
could keep it running for a second or so after the power line is cut.

While they'll keep the VFD controls running for a second or two, they
most certainly will not power the motor for any length of time.



* * * * As long as this is only to be used in a true emergency, what I
would do is set it up to drop power to the VFD (two NC contacts), and to
*short* the power from the VFD to the motor (three NO contacts) so not
only will the power be removed from the motor, but you will also have
regenerative braking.

Cutting power to the VFD and triggering the VFD's e-stop input should
allow it to do some braking during the second or two it's caps keep the
control operating.



* * * * This is likely to not damage the VFD -- because they have
circuitry to sense excess current and to shut themselves down under
those conditions -- but it is not *certain* that it would survive this.
More likely than with the high voltage spikes from opening the circuit
to the motor windings which can fry the output transistors.

* * * * Remember that it is truly an *emergency* stop button only. *When
life and limb are in danger, is the time to hit this -- not just when
you want to walk away from the machine for a while.

The best course is to follow the e-stop wiring guides provided in the
VFD manual.- Hide quoted text -

- Show quoted text -

Gentlemen. As regards properly interfacing the "instant forward -
stop - reverse" lever on the KBC mill with the VFD I have stumbled
upon the following tidbit:

"THREE-WIRE INTERFACE OPERATION"
The 3 wire interface is an industry standard motor control interface.
This function uses two inputs for momentary contact start/stop
control, and a third for selecting forward or reverse direction. To
implement the 3 wire interface, assign 20 [STA] (Start), 21 [STP]
(stop) and 22 [F/R] (Forward/Reverse) to three of the intelligent
input terminals. Use a momentary contact for Start and Stop. Use a
selector switch, such as SPST for the Forward/Reverse input. Be sure
to set the operation command selection A002=01 for input terminal
control of motor.

If you have a motor control interface that needs logic-level control
(rather than momentary pulse control), use the [FW] and [RV] inputs
instead."

(Programming table omitted).

*****

The thing is, this Hitachi VFD to my surprise and delight, yet utter
BEWILDERMENT, is far far beyond a simple "phase converter". I've come
to realize that it is a programmable automation brain. So, I'm not
sure, but out of the avalanche of programming data, I think this is
the "magic tidbit" I've been looking for.

So, to expand on advice some of you have already given, it sounds like
I need to hook the motor leads up to the VFD outputs and then re-route
all of the mill's controls (on/off switch and forward - stop - reverse
toggle lever) to the "logic input buss" terminals and then program
these as per the instructions.

Does that sound right?

Vernon

On Wed, 8 Oct 2008 09:13:35 -0700 (PDT), Vernon
wrote:
On Oct 8, 10:02*am, "Pete C." wrote:
"DoN. Nichols" wrote:

The best course is to follow the e-stop wiring guides provided in the
VFD manual.

Thanks. But is "e-stop" the same as "dynamic braking"? The latter
term is the only thing I see in the glossary.

D: All of the Above.

A true "Emergency Stop" button is: "Cut the main motor power and
trigger the dynamic braking, ignore all other inputs saying Start or
Run while the E-Stop circuit is open, dump or short out the main power
input if you have to, damage the drive by blowing the main SCR's if
you must, shove a chock block into the gears - but whatever you need
to do to make it happen YOU WILL STOP NOW, PERIOD."

In the old days, they would place a huge contactor as a "Crowbar
Safety" so it puts a dead short across the main motor power line, to
blow the main fuses upstream if the service motor contactor welds shut
or gets mechanically stuck and won't open.

Or they put two magnetic contactors in series, one for service and
one for emergencies only, on the theory that two of them won't both
have welded contacts at the same time.

But you only went to that much trouble on things like punch presses,
where people crawl inside to service it and/or they stick their hands
inside the open jaws to load material and remove the finished goods.
And the edict has been issued that This Machine Shall Not Start Up
Unexpectedly, nor fail to shut down when turned off.

-- Bruce --

On Wed, 8 Oct 2008 20:30:36 -0700 (PDT), Vernon
wrote:

On Oct 8, 10:02*am, "Pete C." wrote:
"DoN. Nichols" wrote:

On 2008-10-06, Pete C. wrote:

David Lesher wrote:

* * * * [ ... ]

Get a pushbutton, a big industrial one. Allen Bradley comes to mind. They
are basically Legos; you start with the basic button and add contacts of
the type needed.

It should have 3 contacts rated for the full current of the motor. They
will be closed in OUT mode, but open when pushed in. Wire in series
with all three legs going to the motor..

Have a low current 4th contact going to the VFD shutdown connection.

This will break the power feed to your mill when hit, AND send a shutdown
to the VFD. [It may take a while to turn off, however, as compared to the
button. Maybe even as much a second or two; see what the VFD Fine Manual
says.]

This way, even if the shutdown command does not work, the power *is* off.

The shutdown pushbutton will be expensive new. There are millions surplus
but it will be tricky to mail-order same. If you have a surplus place
nearby....

The E-stop switch belongs on the power feed *to* the VFD, *not* on the
motor leads from the VFD, otherwise you just have a "VFD destruct"
button. The diagrams in the VFD manual should show the proper wiring for
an emergency stop.

* * * * Except that the VFD has a set of big capacitors in there, which
could keep it running for a second or so after the power line is cut.

While they'll keep the VFD controls running for a second or two, they
most certainly will not power the motor for any length of time.



* * * * As long as this is only to be used in a true emergency, what I
would do is set it up to drop power to the VFD (two NC contacts), and to
*short* the power from the VFD to the motor (three NO contacts) so not
only will the power be removed from the motor, but you will also have
regenerative braking.

Cutting power to the VFD and triggering the VFD's e-stop input should
allow it to do some braking during the second or two it's caps keep the
control operating.



* * * * This is likely to not damage the VFD -- because they have
circuitry to sense excess current and to shut themselves down under
those conditions -- but it is not *certain* that it would survive this.
More likely than with the high voltage spikes from opening the circuit
to the motor windings which can fry the output transistors.

* * * * Remember that it is truly an *emergency* stop button only. *When
life and limb are in danger, is the time to hit this -- not just when
you want to walk away from the machine for a while.

The best course is to follow the e-stop wiring guides provided in the
VFD manual.- Hide quoted text -

- Show quoted text -

Gentlemen. As regards properly interfacing the "instant forward -
stop - reverse" lever on the KBC mill with the VFD I have stumbled
upon the following tidbit:

"THREE-WIRE INTERFACE OPERATION"
The 3 wire interface is an industry standard motor control interface.
This function uses two inputs for momentary contact start/stop
control, and a third for selecting forward or reverse direction. To
implement the 3 wire interface, assign 20 [STA] (Start), 21 [STP]
(stop) and 22 [F/R] (Forward/Reverse) to three of the intelligent
input terminals. Use a momentary contact for Start and Stop. Use a
selector switch, such as SPST for the Forward/Reverse input. Be sure
to set the operation command selection A002=01 for input terminal
control of motor.

If you have a motor control interface that needs logic-level control
(rather than momentary pulse control), use the [FW] and [RV] inputs
instead."

(Programming table omitted).

*****

The thing is, this Hitachi VFD to my surprise and delight, yet utter
BEWILDERMENT, is far far beyond a simple "phase converter". I've come
to realize that it is a programmable automation brain. So, I'm not
sure, but out of the avalanche of programming data, I think this is
the "magic tidbit" I've been looking for.

So, to expand on advice some of you have already given, it sounds like
I need to hook the motor leads up to the VFD outputs and then re-route
all of the mill's controls (on/off switch and forward - stop - reverse
toggle lever) to the "logic input buss" terminals and then program
these as per the instructions.

Does that sound right?

Vernon


Sounds like someone hit this Vernon feller a good wack with the
Cluebyfour.

You finally got it.

Ayup..thats what you do.

Makes life somewhat simpler no?

Gunner

On Oct 9, 2:46*am, Gunner wrote:
On Wed, 8 Oct 2008 20:30:36 -0700 (PDT), Vernon
wrote:





On Oct 8, 10:02*am, "Pete C." wrote:
"DoN. Nichols" wrote:

On 2008-10-06, Pete C. wrote:

David Lesher wrote:

* * * * [ ... ]

Get a pushbutton, a big industrial one. Allen Bradley comes to mind. They
are basically Legos; you start with the basic button and add contacts of
the type needed.

It should have 3 contacts rated for the full current of the motor.. They
will be closed in OUT mode, but open when pushed in. Wire in series
with all three legs going to the motor..

Have a low current 4th contact going to the VFD shutdown connection.

This will break the power feed to your mill when hit, AND send a shutdown
to the VFD. [It may take a while to turn off, however, as compared to the
button. Maybe even as much a second or two; see what the VFD Fine Manual
says.]

This way, even if the shutdown command does not work, the power *is* off.

The shutdown pushbutton will be expensive new. There are millions surplus
but it will be tricky to mail-order same. If you have a surplus place
nearby....

The E-stop switch belongs on the power feed *to* the VFD, *not* on the
motor leads from the VFD, otherwise you just have a "VFD destruct"
button. The diagrams in the VFD manual should show the proper wiring for
an emergency stop.

* * * * Except that the VFD has a set of big capacitors in there, which
could keep it running for a second or so after the power line is cut..

While they'll keep the VFD controls running for a second or two, they
most certainly will not power the motor for any length of time.

* * * * As long as this is only to be used in a true emergency, what I
would do is set it up to drop power to the VFD (two NC contacts), and to
*short* the power from the VFD to the motor (three NO contacts) so not
only will the power be removed from the motor, but you will also have
regenerative braking.

Cutting power to the VFD and triggering the VFD's e-stop input should
allow it to do some braking during the second or two it's caps keep the
control operating.

* * * * This is likely to not damage the VFD -- because they have
circuitry to sense excess current and to shut themselves down under
those conditions -- but it is not *certain* that it would survive this.
More likely than with the high voltage spikes from opening the circuit
to the motor windings which can fry the output transistors.

* * * * Remember that it is truly an *emergency* stop button only. *When
life and limb are in danger, is the time to hit this -- not just when
you want to walk away from the machine for a while.

The best course is to follow the e-stop wiring guides provided in the
VFD manual.- Hide quoted text -

- Show quoted text -

Gentlemen. *As regards properly interfacing the "instant forward -
stop - reverse" *lever on the KBC mill with the VFD I have stumbled
upon the following tidbit:

"THREE-WIRE INTERFACE OPERATION"
The 3 wire interface is an industry standard motor control interface.
This function uses two inputs for momentary contact start/stop
control, and a third for selecting forward or reverse direction. *To
implement the 3 wire interface, assign 20 [STA] (Start), 21 [STP]
(stop) and 22 [F/R] (Forward/Reverse) to three of the intelligent
input terminals. *Use a momentary contact for Start and Stop. *Use a
selector switch, such as SPST for the Forward/Reverse input. *Be sure
to set the operation command selection A002=01 for input terminal
control of motor.

If you have a motor control interface that needs logic-level control
(rather than momentary pulse control), use the [FW] and [RV] inputs
instead."

(Programming table omitted).

*****

The thing is, this Hitachi VFD to my surprise and delight, yet utter
BEWILDERMENT, is far far beyond a simple "phase converter". *I've come
to realize that it is a programmable automation brain. *So, I'm not
sure, but out of the avalanche of programming data, I think this is
the "magic tidbit" I've been looking for.

So, to expand on advice some of you have already given, it sounds like
I need to hook the motor leads up to the VFD outputs and then re-route
all of the mill's controls (on/off switch and forward - stop - reverse
toggle lever) to the "logic input buss" terminals and then program
these as per the instructions.

Does that sound right?

Vernon

Sounds like someone hit this Vernon feller a good wack with the
Cluebyfour.

You finally got it. *

Ayup..thats what you do.

Makes life somewhat simpler no?

Gunner- Hide quoted text -

- Show quoted text -

Gunner, you are too funny. Yup, it was truly my "eureka moment". By
the way, I just had the honor and privilege of defending the superior
intelligence and generosity of spirit of the contributors to this
group, thusly.

I went down to a big box hardware store to buy some wire and ring
terminals for the project. I took the VFD in with me. I found the
clerk in the cut wire section. Only after he stopped being busy
taping up and labeling cut wire remnants I told him I might want some
of 'em. As I was about to explain what I was doing I mentioned that I
was not an electrician.

To this he imperiously proclaimed "Well, I am. You've come to the
right place. I can teach you something". But then I explained the
project and showed him the VFD. He flatly exclaimed "You have a
problem. It won't work".

Politely, even sweetly, I said, "Oh, but it will. The guys on
rec.crafts.metalworking said so. The contributors there have vast
experience. There are small business owners including electricians,
electrical engineers, machinists, and experts in automation. I have
utmost faith in 'em".

At that, he backed off a little but was still dubious. He finally
came to the humiliating and painful realization that he was being
taught something new by a clueless newby.

Isn't usenet great!!???

Best wishes and many thanks to all of you.

Vernon

On 2008-10-09, Vernon wrote:

[ ... ]

Gentlemen. As regards properly interfacing the "instant forward -
stop - reverse" lever on the KBC mill with the VFD I have stumbled
upon the following tidbit:

"THREE-WIRE INTERFACE OPERATION"
The 3 wire interface is an industry standard motor control interface.
This function uses two inputs for momentary contact start/stop
control, and a third for selecting forward or reverse direction. To
implement the 3 wire interface, assign 20 [STA] (Start), 21 [STP]
(stop) and 22 [F/R] (Forward/Reverse) to three of the intelligent
input terminals. Use a momentary contact for Start and Stop. Use a
selector switch, such as SPST for the Forward/Reverse input. Be sure
to set the operation command selection A002=01 for input terminal
control of motor.

If you have a motor control interface that needs logic-level control
(rather than momentary pulse control), use the [FW] and [RV] inputs
instead."

I suspect that your forward/stop/reverse switch wants the latter.

And a separate "ON/OFF" switch can be used to remove power from
the VFD when you are not running the mill. This is an advantage,
because the VFD can be damaged by nearby lightning strikes.

The typical forward/stop/reverse switch is like this (sometimes
it will obvious from examination, sometimes it will require decoding how
a wafer switch works. View with a fixed pitch font like Courier to keep
the image from being scrambled.

This first drawing assumes a three phase power input (as your
machine comes wired):

o---------------+--------------(A)
|
(L1)-------o------o |
|
o------+ |
| |
| |
o------+------- | -------------(B)
|
(L2)-------o------o |
|
o---------------+


o------+
|
(L3)-------o------o |
|
o------+-----------------------(C)


L1, L2, and L3 are the input power from the wall.

A, B, and C are the motor winding wires.

In the center position, there is no power to the motor at all.

In the Upper position, L1 connects to A, L2 to B, and L3 to C

In the Lower position, L1 connects to B, L2 to A, and L3 still
to C


Now -- let's assume that we are connecting to the VFD instead:

o---------------+--------------(A)(FWD)
|
(common)(L1)-------o------o |
|
o------+ |
| |
| |
o------+------- | -------------(B)(REV)
|
(L2)-------o------o |
|
o---------------+


o------+
|
(L3)-------o------o |
|
o------+-----------------------(C)



Just take the same switch, don't modify it at all, and connect
L1 to the common ground on the logic terminals.

Connect A to the FWD terminal

Connect B to the REV terminal.

There is probably a wire which is used for the STOP button in
the logic terminals which if connected to ground will cause a momentary
pulse to latch the selected run direction, and which has to be opened to
stop it (with a NC pushbutton).

Just ignore the rest of the terminals on the switch. You don't
need them.

The main power switch hopefully breaks both sides of the 240V
for safety. This should be wired to break the incoming power to the VFD
instead.

(Programming table omitted).

*****

The thing is, this Hitachi VFD to my surprise and delight, yet utter
BEWILDERMENT, is far far beyond a simple "phase converter". I've come
to realize that it is a programmable automation brain. So, I'm not
sure, but out of the avalanche of programming data, I think this is
the "magic tidbit" I've been looking for.

Yes.

So, to expand on advice some of you have already given, it sounds like
I need to hook the motor leads up to the VFD outputs and then re-route
all of the mill's controls (on/off switch and forward - stop - reverse
toggle lever) to the "logic input buss" terminals and then program
these as per the instructions.

Not quite -- but close. The forward/stop/reverse switch is
connected to the "logic input buss", but the main power switch switches
off the VFD's own input power. And that switch can a switch box on the
wall instead of a switch on the machine, since you only turn it on
before using the machine, and off when done with the machine, and use
the forward/stop/reverse switch for most other things.

Actually -- when changing cutters, you really *should* turn off
the power fully, since it can get rather exciting if the spindle
suddenly spins up while you are gripping the milling cuter.

Does that sound right?

Close.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---