Now this 3 phase mill can run from single phase (regular 220v plug),
it stops in 0.5 seconds thanks to electric braking, and it also
reverses, which is something it was not capable of before.

In addition to the old gearbox speed changer, speed can also be varied
with a pot (0-60 Hz).

All of the above make this machine more desirable.

http://yabe.algebra.com/~ichudov/mis...25-Mill-Drill/

Ignoramus7041 wrote in news:-
:

http://yabe.algebra.com/~ichudov/mis...25-Mill-Drill/

Ahhhh! Ventilated electronics enclosure mounted below the table of a
metalworking machine tool.
runs and hides

On 2009-08-30, Charles U Farley wrote:
Ignoramus7041 wrote in news:-
:

http://yabe.algebra.com/~ichudov/mis...25-Mill-Drill/

Ahhhh! Ventilated electronics enclosure mounted below the table of a
metalworking machine tool.
runs and hides

Yes, good point, I was going to put a cover above it. Have not gotten
to it yet.

i

Do you know if the company is still in business for parts?

My Arboga radial arm drill broke the power down while doing a 3" hole this
summer. Its on my winter repair list.

Karl

On 2009-08-30, Karl Townsend wrote:
Do you know if the company is still in business for parts?

My Arboga radial arm drill broke the power down while doing a 3" hole this
summer. Its on my winter repair list.


Do you know what broke exactly?

I looked and could not find their website, I suspect that they were
bought out by Wilton (WMH tool group).

i

On Sun, 30 Aug 2009 16:20:51 -0500, Ignoramus7041
wrote:

Now this 3 phase mill can run from single phase (regular 220v plug),
it stops in 0.5 seconds thanks to electric braking, and it also
reverses, which is something it was not capable of before.

In addition to the old gearbox speed changer, speed can also be varied
with a pot (0-60 Hz).

All of the above make this machine more desirable.

http://yabe.algebra.com/~ichudov/mis...25-Mill-Drill/


Seriously big pending ****up. That VFD needs to go on the BACKSIDE of
the mill column.

You are going to get chips down into the top of it in its present
location and all the magic smoke is going to come out of it.

At the very very least..put a horizontal thin plate aprox 1" above the
upper vent grid to protect it from **** going down the grid.

Trust me on this. It WILL happen.


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 2009-08-31, Gunner Asch wrote:
On Sun, 30 Aug 2009 16:20:51 -0500, Ignoramus7041
wrote:

Now this 3 phase mill can run from single phase (regular 220v plug),
it stops in 0.5 seconds thanks to electric braking, and it also
reverses, which is something it was not capable of before.

In addition to the old gearbox speed changer, speed can also be varied
with a pot (0-60 Hz).

All of the above make this machine more desirable.

http://yabe.algebra.com/~ichudov/mis...25-Mill-Drill/


Seriously big pending ****up. That VFD needs to go on the BACKSIDE of
the mill column.

You are going to get chips down into the top of it in its present
location and all the magic smoke is going to come out of it.

At the very very least..put a horizontal thin plate aprox 1" above the
upper vent grid to protect it from **** going down the grid.

Trust me on this. It WILL happen.

Yes, I will put some sort of a thin plate over it asap.

Good catch Gunner. I actually thought to do it, then completely
forgot.

I am reluctant to put it on the back, it will make it hard to
program.

i

Do you know if the company is still in business for parts?

My Arboga radial arm drill broke the power down while doing a 3" hole
this
summer. Its on my winter repair list.


Do you know what broke exactly?

Nope, I just engaged the power down and it wasn't there any more. Means you
got to stand there and push down by hand - sux on a deep large hole.

Karl

On 2009-08-31, Karl Townsend wrote:

Do you know if the company is still in business for parts?

My Arboga radial arm drill broke the power down while doing a 3" hole
this
summer. Its on my winter repair list.


Do you know what broke exactly?

Nope, I just engaged the power down and it wasn't there any more. Means you
got to stand there and push down by hand - sux on a deep large hole.

This makes me hope that it is something simple, some intentional weak
link. Maybe there is some roll pin that is purposely made to break
under excess load.

i

Do you know what broke exactly?

Nope, I just engaged the power down and it wasn't there any more. Means
you
got to stand there and push down by hand - sux on a deep large hole.

This makes me hope that it is something simple, some intentional weak
link. Maybe there is some roll pin that is purposely made to break
under excess load.

Very likely, being able to talk to somebody that knows this machine or
having an assembly drawing would be worth its weight in gold.

Karl

On Sun, 30 Aug 2009 19:16:19 -0500, Ignoramus7041
wrote:

On 2009-08-31, Gunner Asch wrote:
On Sun, 30 Aug 2009 16:20:51 -0500, Ignoramus7041
wrote:

Now this 3 phase mill can run from single phase (regular 220v plug),
it stops in 0.5 seconds thanks to electric braking, and it also
reverses, which is something it was not capable of before.

In addition to the old gearbox speed changer, speed can also be varied
with a pot (0-60 Hz).

All of the above make this machine more desirable.

http://yabe.algebra.com/~ichudov/mis...25-Mill-Drill/


Seriously big pending ****up. That VFD needs to go on the BACKSIDE of
the mill column.

You are going to get chips down into the top of it in its present
location and all the magic smoke is going to come out of it.

At the very very least..put a horizontal thin plate aprox 1" above the
upper vent grid to protect it from **** going down the grid.

Trust me on this. It WILL happen.

Yes, I will put some sort of a thin plate over it asap.

Good catch Gunner. I actually thought to do it, then completely
forgot.

I am reluctant to put it on the back, it will make it hard to
program.

i

You already have a "remote control" that sets forward/off/reverse and
speed, right?

A simple Form C toggle switch and a pot in a tiny little box mounted
somewhere on the face of the machine.

Right?

Ive got a number of mills with the VFD mounted in boxes on the wall
Behind the mill, with the simple control device mounted on the head.

Its not rocket science, and it makes the machine safe, secure and
unlikely for the magic smoke to come out.

And its quite easy to simply change the wiring on the existing power
switch to run directly to the VFD and the head switch (I didnt check)
control the VFD, rather than the 3ph power directly.


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 2009-08-31, Gunner Asch wrote:
You already have a "remote control" that sets forward/off/reverse and
speed, right?

Yes

A simple Form C toggle switch and a pot in a tiny little box mounted
somewhere on the face of the machine.

Right?

Exactly.

Ive got a number of mills with the VFD mounted in boxes on the wall
Behind the mill, with the simple control device mounted on the head.

Its not rocket science, and it makes the machine safe, secure and
unlikely for the magic smoke to come out.

And its quite easy to simply change the wiring on the existing power
switch to run directly to the VFD and the head switch (I didnt check)
control the VFD, rather than the 3ph power directly.

Well, yes, but it is an on/off switch, and I need a forward/reverse
switch.

Anyway, I did put a cover over the top of the VFD last night, it
should be fine as is.

i

In article ,
Ignoramus25738 wrote:

On 2009-08-31, Gunner Asch wrote:
You already have a "remote control" that sets forward/off/reverse and
speed, right?

Yes

A simple Form C toggle switch and a pot in a tiny little box mounted
somewhere on the face of the machine.

Right?

Exactly.

Ive got a number of mills with the VFD mounted in boxes on the wall
Behind the mill, with the simple control device mounted on the head.

Its not rocket science, and it makes the machine safe, secure and
unlikely for the magic smoke to come out.

And its quite easy to simply change the wiring on the existing power
switch to run directly to the VFD and the head switch (I didn't check)
control the VFD, rather than the 3ph power directly.

Well, yes, but it is an on/off switch, and I need a forward/reverse
switch.

Anyway, I did put a cover over the top of the VFD last night, it
should be fine as is.

Chips are far too clever for a simple cover to work for very long,
unless the cover is so tight that airflow is blocked. One can cut the
leakage rate down with some fine-mesh metal screening, but even that
isn't perfect.

Real factories often put the VFDs in a closed metal box, precisely to
protect the VFD from factory dust, dirt, chips, gasses, et al. And from
confused button-pushers, but that's another story.

It's easy to build a remote-control box for a VFD, which is mounted up
high on the wall, behind the mill, out of the chip impact zone. Put the
VFD's displays at eye height and programming (a rare activity) is easy
enough.

Joe Gwinn

On Mon, 31 Aug 2009 07:12:52 -0500, Ignoramus25738
wrote:

On 2009-08-31, Gunner Asch wrote:
You already have a "remote control" that sets forward/off/reverse and
speed, right?

Yes

A simple Form C toggle switch and a pot in a tiny little box mounted
somewhere on the face of the machine.

Right?

Exactly.

Ive got a number of mills with the VFD mounted in boxes on the wall
Behind the mill, with the simple control device mounted on the head.

Its not rocket science, and it makes the machine safe, secure and
unlikely for the magic smoke to come out.

And its quite easy to simply change the wiring on the existing power
switch to run directly to the VFD and the head switch (I didnt check)
control the VFD, rather than the 3ph power directly.

Well, yes, but it is an on/off switch, and I need a forward/reverse
switch.

Anyway, I did put a cover over the top of the VFD last night, it
should be fine as is.

i

Lets hope so. Though I suspect, based on my years as a machine tool
mechanic in commercial machine shops...that it wont blow up until the
new owners uses it for more than 30 days...or maybe not. Shrug...

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 Mon, 31 Aug 2009 09:57:31 -0400, Joseph Gwinn
wrote:

In article ,
Ignoramus25738 wrote:

On 2009-08-31, Gunner Asch wrote:
You already have a "remote control" that sets forward/off/reverse and
speed, right?

Yes

A simple Form C toggle switch and a pot in a tiny little box mounted
somewhere on the face of the machine.

Right?

Exactly.

Ive got a number of mills with the VFD mounted in boxes on the wall
Behind the mill, with the simple control device mounted on the head.

Its not rocket science, and it makes the machine safe, secure and
unlikely for the magic smoke to come out.

And its quite easy to simply change the wiring on the existing power
switch to run directly to the VFD and the head switch (I didn't check)
control the VFD, rather than the 3ph power directly.

Well, yes, but it is an on/off switch, and I need a forward/reverse
switch.

Anyway, I did put a cover over the top of the VFD last night, it
should be fine as is.

Chips are far too clever for a simple cover to work for very long,
unless the cover is so tight that airflow is blocked. One can cut the
leakage rate down with some fine-mesh metal screening, but even that
isn't perfect.

Real factories often put the VFDs in a closed metal box, precisely to
protect the VFD from factory dust, dirt, chips, gasses, et al. And from
confused button-pushers, but that's another story.

It's easy to build a remote-control box for a VFD, which is mounted up
high on the wall, behind the mill, out of the chip impact zone. Put the
VFD's displays at eye height and programming (a rare activity) is easy
enough.

Joe Gwinn


Indeed. Well said.


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.

In addition to the old gearbox speed changer, speed can also be varied
with a pot (0-60 Hz).


I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches
in a separate box would be a lot more convenient. What are typical
specs for a potentiometer for one of these? Something I could pick up
at Radio Shack or do I need to order on line? Under what section of
the manual would you go looking for specs if it's something that
varies by manufacturer and model? I only read enough of the manual to
get my mill up and running so I could play with it. Now that I've had
it for several months, it's time to make improvements.

RWL

On 2009-09-01, GeoLane at PTD dot NET GeoLane wrote:

In addition to the old gearbox speed changer, speed can also be varied
with a pot (0-60 Hz).


I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches
in a separate box would be a lot more convenient. What are typical
specs for a potentiometer for one of these? Something I could pick up
at Radio Shack or do I need to order on line? Under what section of
the manual would you go looking for specs if it's something that
varies by manufacturer and model? I only read enough of the manual to
get my mill up and running so I could play with it. Now that I've had
it for several months, it's time to make improvements.

Your VFD manual does not seem to say what the rating for the pot
should be. Mine said, IIRC, that it should be between 1k and 10k. I
used a 1k pot because I have a few of those. 5k should work well. You
can call Teco and ask to be sure.

If you want a pot and an on-off switch, then you can buy a pot with a
built in switch, those are widely available. They have two contacts
for a switch and three for a pot, usually they click and turn off when
fully turned counterclockwise. So you can wire that switch to turn off
the current when the switch is off, and turn on and ramp up the
frequency as you turn the knob clockwise.

Now if you want a pot and a forward/off/reverse switch, then you need
to have them separately, pretty much.

It is really up to you as to what you want, for instance whether you
want to power tap on the mill.

Radio Shack could be pricey, but the easiest option of all. Most
likely you need a 5k pot.

i

On Mon, 31 Aug 2009 21:48:17 -0400, GeoLane at PTD dot NET GeoLane at
PTD dot NET wrote:


In addition to the old gearbox speed changer, speed can also be varied
with a pot (0-60 Hz).


I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches
in a separate box would be a lot more convenient. What are typical
specs for a potentiometer for one of these? Something I could pick up
at Radio Shack or do I need to order on line? Under what section of
the manual would you go looking for specs if it's something that
varies by manufacturer and model? I only read enough of the manual to
get my mill up and running so I could play with it. Now that I've had
it for several months, it's time to make improvements.

RWL


Look in the wiring diagrams and it should show you what value the pot is
supposed to be.

Generally....0-5k...some are 0-10k, others are different.

This is not something to guess at.

If you do..you will never get it going fast enough...or ever get it
going, or ever get it going slow enough.....

G

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 1 Sep 2009 06:09:17 GMT, "DoN. Nichols" wrote:

On 2009-09-01, GeoLane at PTD dot NET GeoLane wrote:

In addition to the old gearbox speed changer, speed can also be varied
with a pot (0-60 Hz).


I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches
in a separate box would be a lot more convenient. What are typical
specs for a potentiometer for one of these? Something I could pick up
at Radio Shack or do I need to order on line? Under what section of
the manual would you go looking for specs if it's something that
varies by manufacturer and model? I only read enough of the manual to
get my mill up and running so I could play with it. Now that I've had
it for several months, it's time to make improvements.

Typical pot is a 5K or 10K linear pot with a 2W power rating.

As for the switch -- make it a SPDTCO (Single Pole Single Throws
Center Off) switch so you can use it to select forward stop or reverse.
(It might be good to have one of the locking toggles with the
pull-to-release handles, so you can't accidentally go from forward to
reverse when you really want to stop.

There should be wiring diagrams for how to connect such
switches, as well as ones for using three push buttons (forward,
reverse, and stop). For the latter, a red mushroom actuator for ths top
switch with a locking mode so you have to twist it or pull it to reset
the stop. That way, you just bring your hand up and slap it to stop in
an emergency.

Enjoy,
DoN.


Very well said!

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 2009-09-01, Gunner Asch wrote:
On 1 Sep 2009 06:09:17 GMT, "DoN. Nichols" wrote:

On 2009-09-01, GeoLane at PTD dot NET GeoLane wrote:

In addition to the old gearbox speed changer, speed can also be varied
with a pot (0-60 Hz).


I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches
in a separate box would be a lot more convenient. What are typical
specs for a potentiometer for one of these? Something I could pick up
at Radio Shack or do I need to order on line? Under what section of
the manual would you go looking for specs if it's something that
varies by manufacturer and model? I only read enough of the manual to
get my mill up and running so I could play with it. Now that I've had
it for several months, it's time to make improvements.

Typical pot is a 5K or 10K linear pot with a 2W power rating.

As for the switch -- make it a SPDTCO (Single Pole Single Throws

Did you mean double throw?

Got a source for those?

i

Center Off) switch so you can use it to select forward stop or reverse.
(It might be good to have one of the locking toggles with the
pull-to-release handles, so you can't accidentally go from forward to
reverse when you really want to stop.

There should be wiring diagrams for how to connect such
switches, as well as ones for using three push buttons (forward,
reverse, and stop). For the latter, a red mushroom actuator for ths top
switch with a locking mode so you have to twist it or pull it to reset
the stop. That way, you just bring your hand up and slap it to stop in
an emergency.

Enjoy,
DoN.


Very well said!

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.

The switch 's resistance should be much less than the input impedance,
but big enough so as not to exceed the limit on current produced by
the CC terminal.

5k should most likely work and those are very common pots.

I put a 1k pot in my drive the other day and it works great.

i

On 2009-09-01, DoN. Nichols wrote:
On 2009-09-01, Gunner Asch wrote:

[ ... ]

Look in the wiring diagrams and it should show you what value the pot is
supposed to be.

Generally....0-5k...some are 0-10k, others are different.

Yes -- but these are common ratings.

This is not something to guess at.

If you do..you will never get it going fast enough...or ever get it
going, or ever get it going slow enough.....

Hmm ... that effect would be more if it were being wired and
used as a rheostat instead of a potentiometer. Normally, the VFD has
three pins for use with a pot. One is common ground, one puts out 10V
or 5V, and the third connects to the wiper. Usually, the output voltage
is capable of sufficient current for 1K, 5K or 10K, and what really
matters is the voltage which the wiper returns to the control input,
which should cover the same range with any reasonable value of
potentiometer. Go really too high, and you are likely to pick up noise
which will cause the speed to vary a lot at mid range settings. Go
really too low, and the 5V or 10V output can't provide enough current,
and the voltage will be too low so you can't get enough speed. But
anything from 1K to 10K should be fine -- with values beyond that
possibly encountering problems. But it is not a critical value.

Enjoy,
DoN.

I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches
in a separate box would be a lot more convenient. What are typical
specs for a potentiometer for one of these?
RWL


Look in the wiring diagrams and it should show you what value the pot is
supposed to be.

Generally....0-5k...some are 0-10k, others are different.


Gunner


Thanks Gunner, Iggy, Don
I scanned through the manual looking for the wiring diagram and next
to the potentiometer it says "10k ?" I"m not sure why the "?" is
printed in the book but that's what it says. I looked at the on line
listing at Radio Shack - not too pricey, about $3. The only problem
is, they only list 0.5W potentiometers and Don had mentioned it ought
to be 2 Watts.

I looked in the Mouser catalog and I spot two that would probably do
the job. One's a high precision single turn pot EUP-1400-10k for
$4.15. The other is listed as a 53 series industrial pot with a 25k
rotational life expectancy. 785-531C10k for $6.76 Both of these
handle 2 watts.

It looks like the control switches for my VFD should be momentary
switches.

RWL

On 2009-09-02, GeoLane at PTD dot NET GeoLane wrote:


I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches
in a separate box would be a lot more convenient. What are typical
specs for a potentiometer for one of these?
RWL


Look in the wiring diagrams and it should show you what value the pot is
supposed to be.

Generally....0-5k...some are 0-10k, others are different.


Gunner


Thanks Gunner, Iggy, Don
I scanned through the manual looking for the wiring diagram and next
to the potentiometer it says "10k ?" I"m not sure why the "?" is
printed in the book but that's what it says. I looked at the on line
listing at Radio Shack - not too pricey, about $3. The only problem
is, they only list 0.5W potentiometers and Don had mentioned it ought
to be 2 Watts.

If the control voltage is 10 volts, then a 10k potentiometer would
dissipate 10v*10v/10000ohm = 0.01 watts. You do not need a 2 watt 10k pot.

I looked in the Mouser catalog and I spot two that would probably do
the job. One's a high precision single turn pot EUP-1400-10k for
$4.15. The other is listed as a 53 series industrial pot with a 25k
rotational life expectancy. 785-531C10k for $6.76 Both of these
handle 2 watts.

It looks like the control switches for my VFD should be momentary
switches.

You can always test that with a wire that has two bare ends. Just
touch two appropriate control contacts, while staying away from R,S,T
and U,V,W and other big screw terminals.

i
RWL

On 2009-09-01, Ignoramus15363 wrote:
On 2009-09-01, Gunner Asch wrote:
On 1 Sep 2009 06:09:17 GMT, "DoN. Nichols" wrote:


[ ... ]

Typical pot is a 5K or 10K linear pot with a 2W power rating.

As for the switch -- make it a SPDTCO (Single Pole Single Throws

Did you mean double throw?

Yes, I did.

Got a source for those?

For the usual ones -- try Mouser, Digi-Key, and the other
electronic suppliers.

For the locking handle ones -- those I stumble across at
hamfests -- occasionally.

O.K. Mouser Electronics has them -- but not cheap. Look at:

http://www.mouser.com/ProductDetail/Honeywell/2TL1-1A/?qs=sGAEpiMZZMtygI3JAGOxU%2f5ZR3DSiS2Q

assuming that still reaches it. If not. look for Mouser part number
785-2TL1-1A (A Honeywell switch -- about $40.00 in unit quantities.

The one shown has to have the handle pulled to switch from any
position to any position. There are some which will switch to one side
only without pulling, and the other side requires pulling. Others can
be switched from either "ON" position to the center "OFF" position, but
must be pulled to switch to either "ON".

You deal with enough surplus stuff so once you know what they
look like, you can keep your eyes open for them. They are normally used
for things like activating munitions in an aircraft, where you don't
want someone to accidentally switch something explosive on. :-)

On eBay -- these look like possibilities:

300333989154

This one is lacking the center off, but it has a close-up which
shows how the locking works.

330259446730

But if you have to *buy* switches *new*, look for large
pushbuttons, with the locking mushroom switch for the panic stop
function. You can get those at places like Grainger, if you have the
ability to buy there.

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 2009-09-02, DoN. Nichols wrote:
O.K. Mouser Electronics has them -- but not cheap. Look at:

http://www.mouser.com/ProductDetail/Honeywell/2TL1-1A/?qs=sGAEpiMZZMtygI3JAGOxU%2f5ZR3DSiS2Q

assuming that still reaches it. If not. look for Mouser part number
785-2TL1-1A (A Honeywell switch -- about $40.00 in unit quantities.

The one shown has to have the handle pulled to switch from any
position to any position. There are some which will switch to one side
only without pulling, and the other side requires pulling. Others can
be switched from either "ON" position to the center "OFF" position, but
must be pulled to switch to either "ON".

You deal with enough surplus stuff so once you know what they
look like, you can keep your eyes open for them. They are normally used
for things like activating munitions in an aircraft, where you don't
want someone to accidentally switch something explosive on. :-)

On eBay -- these look like possibilities:

300333989154

This one is lacking the center off, but it has a close-up which
shows how the locking works.

330259446730

But if you have to *buy* switches *new*, look for large
pushbuttons, with the locking mushroom switch for the panic stop
function. You can get those at places like Grainger, if you have the
ability to buy there.

Don, I thought that you initially discussed a pot/switch combination?

i

In article ,
Ignoramus15363 wrote:

The switch 's resistance should be much less than the input impedance,
but big enough so as not to exceed the limit on current produced by
the CC terminal.

5k should most likely work and those are very common pots.

I put a 1k pot in my drive the other day and it works great.

That will be at the lower limit, but should be just fine.

VFD makers specify 2 watt pots for mechanical robustness, not electrical
load. Nor do you want machine vibration to cause the pot to walk.

One thing about the Forward-Off-Reverse switch: Do not make it too easy
to operate, or the machine may start when you accidentally brush the
switch. The classic scenario is that one is setting things up, and gets
chopped up when the machine starts unexpectedly. So use nice big and
clunky switches, even though the current is maybe 10 milliamps.

Joe Gwinn



On 2009-09-01, DoN. Nichols wrote:
On 2009-09-01, Gunner Asch wrote:

[ ... ]

Look in the wiring diagrams and it should show you what value the pot is
supposed to be.

Generally....0-5k...some are 0-10k, others are different.

Yes -- but these are common ratings.

This is not something to guess at.

If you do..you will never get it going fast enough...or ever get it
going, or ever get it going slow enough.....

Hmm ... that effect would be more if it were being wired and
used as a rheostat instead of a potentiometer. Normally, the VFD has
three pins for use with a pot. One is common ground, one puts out 10V
or 5V, and the third connects to the wiper. Usually, the output voltage
is capable of sufficient current for 1K, 5K or 10K, and what really
matters is the voltage which the wiper returns to the control input,
which should cover the same range with any reasonable value of
potentiometer. Go really too high, and you are likely to pick up noise
which will cause the speed to vary a lot at mid range settings. Go
really too low, and the 5V or 10V output can't provide enough current,
and the voltage will be too low so you can't get enough speed. But
anything from 1K to 10K should be fine -- with values beyond that
possibly encountering problems. But it is not a critical value.

Enjoy,
DoN.

On 2009-09-02, GeoLane at PTD dot NET GeoLane wrote:


I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches
in a separate box would be a lot more convenient. What are typical
specs for a potentiometer for one of these?
RWL


Look in the wiring diagrams and it should show you what value the pot is
supposed to be.

Generally....0-5k...some are 0-10k, others are different.


Gunner


Thanks Gunner, Iggy, Don
I scanned through the manual looking for the wiring diagram and next
to the potentiometer it says "10k ?" I"m not sure why the "?" is

Are you sure that is not an Omega with part of the printing
missing? I can't get my editor/system to create one, but you can use
wikipedia to display it:

http://en.wikipedia.org/wiki/Omega

Anyway -- the upper case Omega symbol is commonly used as shorthand for
"Ohms", so that is saying "10 K Ohms".

printed in the book but that's what it says. I looked at the on line
listing at Radio Shack - not too pricey, about $3. The only problem
is, they only list 0.5W potentiometers and Don had mentioned it ought
to be 2 Watts.

Some of the makers suggest 2 Watt pots. One reason is that
there is more resistance element area so it will run longer before it
gets noisy. Even at worst case (the DC motor controller which puts 20 V
across the pot, and using a 1K pot instead of a 5K pot, we are still
really under 1/2 Watt.

But -- the larger 2W pots generally have a better feel and
greater ease setting a particular value, so I would use them anyway.

I looked in the Mouser catalog and I spot two that would probably do
the job. One's a high precision single turn pot EUP-1400-10k for
$4.15. The other is listed as a 53 series industrial pot with a 25k
rotational life expectancy. 785-531C10k for $6.76 Both of these
handle 2 watts.

O.K. The first one looks nice. 270 degree rotation is normal,
but when it said "single turn" and "precision" I was afraid that it had
no stops so it would keep going from 0 up to full and then back to zero.
These are used for some instrumentation type tasks, but would be poor
for controls of this sort. However, what you have found should be a
very nice one. The wirewound element will work well for a long time.
And they claim 100K rotational life for the first one.

I can't seem to find the second one by that part number.

It looks like the control switches for my VFD should be momentary
switches.

That depends. Usually there are usually wiring configurations
for momentary pushbuttons (with a NC (Normally Closed) pushbutton for
the stop), or for rotary or toggle switches). (Different pages in the
manual, usually.)

If retrofitting a machine which had a drum switch, I would use
the continuous contact wiring pattern, selecting the proper contacts out
of the drum switch, so I could continue to use the same control that I
was accustomed to.

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 2009-09-02, Ignoramus15363 wrote:
On 2009-09-02, DoN. Nichols wrote:
O.K. Mouser Electronics has them -- but not cheap. Look at:

http://www.mouser.com/ProductDetail/Honeywell/2TL1-1A/?qs=sGAEpiMZZMtygI3JAGOxU%2f5ZR3DSiS2Q

assuming that still reaches it. If not. look for Mouser part number
785-2TL1-1A (A Honeywell switch -- about $40.00 in unit quantities.

The one shown has to have the handle pulled to switch from any
position to any position. There are some which will switch to one side
only without pulling, and the other side requires pulling. Others can
be switched from either "ON" position to the center "OFF" position, but
must be pulled to switch to either "ON".

You deal with enough surplus stuff so once you know what they
look like, you can keep your eyes open for them. They are normally used
for things like activating munitions in an aircraft, where you don't
want someone to accidentally switch something explosive on. :-)

[ ... ]

Don, I thought that you initially discussed a pot/switch combination?

No -- that was someone else. The combination would limit the
ability to get really slow running for positioning a chuck or something
similar. (You don't want to run the motor for any significant time at
that low a speed unless you have made provisions for an external fan to
force air through the motor.)

Also -- the switch in the pot knob is a bit harder to shut off
in a hurry. The red mushroom panic switch is best, next is the usual
drum switch wired to control the VFD.

I actually have a switch which I intend to use when I put three
phase on my Clausing. It is a lever in a pleated rubber boot which
rotates a shaft with cams operating three switches -- one at the zero
center position, and one switch for each direction of travel. But the
cam also has a 1/4" hex socket which can accept the shaft of a
potentiometer and which rotates through the standard 270 degrees. So
what I want is a 10K pot with a center tap so I can wire it for half on
each side of the center off position, using the cam switches to select
the direction, and the half of the pot operated by the lever to select
the speed. (The assembly came from a hamfest, and I have no idea where
to get more of them, but I knew what I wanted it for as soon as I saw
it. :-)

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 Mon, 31 Aug 2009 21:48:17 -0400, GeoLane at PTD dot NET
GeoLane at PTD dot NET wrote:


In addition to the old gearbox speed changer, speed can also be varied
with a pot (0-60 Hz).


I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches
in a separate box would be a lot more convenient. What are typical
specs for a potentiometer for one of these? Something I could pick up
at Radio Shack or do I need to order on line? Under what section of
the manual would you go looking for specs if it's something that
varies by manufacturer and model? I only read enough of the manual to
get my mill up and running so I could play with it. Now that I've had
it for several months, it's time to make improvements.

RWL

VFDs supply the speed pot from a low impedance DC
source typically 10V or less and the pot slider is almost
completely unloaded. This makes the choice of pot value very non
critical - any pot resistance between 3 and 10kohm is typically
recommended as suitable and an even wider range would make little
difference.

Power dissipation is also very low. Even in the worst
case scenario, with the lowest value pot, dissipation is much
less than 1/4W so even small radio type pots are perfectly
usable. However you may prefer the mechanical ruggedness of a pot
with higher power rating.

What is seldom mentioned, but important in practice,
is the resistance law. Most wirewound and many film pots are
linear law which is not very suitable for a machine tool working
over a wide range of work/cutter diameter and speeds. The useful
low speed end is limited to narrow region near anticlockwise.
What is preferable is is a log law pot as this opens up the low
speed end and gives a close approximation to equal % speed change
for equal pot angle change over the whole speed range.

Log law radio type pots are easy to find but heavy duty
types are much less common. A solution that I find preferable is
switched speed setting. The 12 step series resistor sequence

100 Ohm
120
150
180
270
330
390
470
560
680
820
Gives a constant 20% speed change per step which is about
as close as is ever needed in typical machine tool use
For more VFD information try "Electric Motors"- second
edition- Jim Cox
Pentagrid

On Thu, 03 Sep 2009 09:45:23 +0100, wrote:

On Mon, 31 Aug 2009 21:48:17 -0400, GeoLane at PTD dot NET
GeoLane at PTD dot NET wrote:


In addition to the old gearbox speed changer, speed can also be varied
with a pot (0-60 Hz).


I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches
in a separate box would be a lot more convenient. What are typical
specs for a potentiometer for one of these? Something I could pick up
at Radio Shack or do I need to order on line? Under what section of
the manual would you go looking for specs if it's something that
varies by manufacturer and model? I only read enough of the manual to
get my mill up and running so I could play with it. Now that I've had
it for several months, it's time to make improvements.

RWL

VFDs supply the speed pot from a low impedance DC
source typically 10V or less and the pot slider is almost
completely unloaded. This makes the choice of pot value very non
critical - any pot resistance between 3 and 10kohm is typically
recommended as suitable and an even wider range would make little
difference.

Power dissipation is also very low. Even in the worst
case scenario, with the lowest value pot, dissipation is much
less than 1/4W so even small radio type pots are perfectly
usable. However you may prefer the mechanical ruggedness of a pot
with higher power rating.

What is seldom mentioned, but important in practice,
is the resistance law. Most wirewound and many film pots are
linear law which is not very suitable for a machine tool working
over a wide range of work/cutter diameter and speeds. The useful
low speed end is limited to narrow region near anticlockwise.
What is preferable is is a log law pot as this opens up the low
speed end and gives a close approximation to equal % speed change
for equal pot angle change over the whole speed range.

Log law radio type pots are easy to find but heavy duty
types are much less common. A solution that I find preferable is
switched speed setting. The 12 step series resistor sequence

100 Ohm
120
150
180
270
330
390
470
560
680
820
Gives a constant 20% speed change per step which is about
as close as is ever needed in typical machine tool use
For more VFD information try "Electric Motors"- second
edition- Jim Cox
Pentagrid


Interesting commentary. Thanks!!

Gunner

"Somewhere a True Believer is training to kill you. He is training with
minimum food or water,in austere conditions, day and night. The only thing
clean on him is his weapon. He doesn't worry about what workout to do---
his rucksack weighs what it weighs, and he runs until the enemy stops chasing him.
The True Believer doesn't care 'how hard it is'; he knows he either wins or he dies.
He doesn't go home at 1700; he is home. He knows only the 'Cause.' Now, who wants to quit?"

NCOIC of the Special Forces Assessment and Selection Course in a welcome speech to new SF candidates

On 3 Sep 2009 03:33:40 GMT, "DoN. Nichols"
wrote:


Thanks Gunner, Iggy, Don
I scanned through the manual looking for the wiring diagram and next
to the potentiometer it says "10k ?" I"m not sure why the "?" is


Are you sure that is not an Omega with part of the printing missing?

That was a good thought. I ran upstairs and looked in the printed
manual. There it is printed as the ohm sign, so it is 10,000 ohms.
When I made my previous post, I had been looking in the manual that I
had downloaded as a pdf file and that's where the omega appears as the
"?". I tried using copy and paste from the windows character map to
paste an ohm symbol into this reply, and it came out as a question
mark rather than an omega, so on an electronic file, the omega is
being misinterpreted by the computer as a question mark.

RWL

GeoLane at PTD dot NET wrote:
On 3 Sep 2009 03:33:40 GMT, "DoN. Nichols"
wrote:


Thanks Gunner, Iggy, Don
I scanned through the manual looking for the wiring diagram and next
to the potentiometer it says "10k ?" I"m not sure why the "?" is


Are you sure that is not an Omega with part of the printing missing?

That was a good thought. I ran upstairs and looked in the printed
manual. There it is printed as the ohm sign, so it is 10,000 ohms.
When I made my previous post, I had been looking in the manual that I
had downloaded as a pdf file and that's where the omega appears as the
"?". I tried using copy and paste from the windows character map to
paste an ohm symbol into this reply, and it came out as a question
mark rather than an omega, so on an electronic file, the omega is
being misinterpreted by the computer as a question mark.

Does ALT234 (Ω)work?

--Winston

On 2009-09-04, Winston wrote:
GeoLane at PTD dot NET wrote:
On 3 Sep 2009 03:33:40 GMT, "DoN. Nichols"
wrote:

[ ... ]

Are you sure that is not an Omega with part of the printing missing?

That was a good thought. I ran upstairs and looked in the printed
manual. There it is printed as the ohm sign, so it is 10,000 ohms.
When I made my previous post, I had been looking in the manual that I
had downloaded as a pdf file and that's where the omega appears as the
"?". I tried using copy and paste from the windows character map to
paste an ohm symbol into this reply, and it came out as a question
mark rather than an omega, so on an electronic file, the omega is
being misinterpreted by the computer as a question mark.

Does ALT234 (?)work?

Well ... it shows up as a '?' here, which means that it is using
the section of the extended ASCII characterset with represents control
characters with the parity bit set instead of clear. Sun refuses to
display these -- at least with the ISO-8859-15 characterset which I use.
Perhaps it is characterset dependent. And assuming that the 234 in
ALT234 is an octal number, it does land in the parity-bit-set control
character range (0x9c, with 0x80 through 0x9f being the extended control
characters.

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 2009-09-04, Winston wrote:
GeoLane at PTD dot NET wrote:
On 3 Sep 2009 03:33:40 GMT, "DoN. Nichols"
wrote:

[ ... ]

Are you sure that is not an Omega with part of the printing missing?
That was a good thought. I ran upstairs and looked in the printed
manual. There it is printed as the ohm sign, so it is 10,000 ohms.
When I made my previous post, I had been looking in the manual that I
had downloaded as a pdf file and that's where the omega appears as the
"?". I tried using copy and paste from the windows character map to
paste an ohm symbol into this reply, and it came out as a question
mark rather than an omega, so on an electronic file, the omega is
being misinterpreted by the computer as a question mark.
Does ALT234 (?)work?

Well ... it shows up as a '?' here, which means that it is using
the section of the extended ASCII characterset with represents control
characters with the parity bit set instead of clear. Sun refuses to
display these -- at least with the ISO-8859-15 characterset which I use.
Perhaps it is characterset dependent. And assuming that the 234 in
ALT234 is an octal number, it does land in the parity-bit-set control
character range (0x9c, with 0x80 through 0x9f being the extended control
characters.

Yes, that was Unicode UTF-8.

Just checking. Thanks DoN.

--Winston

GeoLane at PTD dot NET wrote:

In addition to the old gearbox speed changer, speed can also be varied
with a pot (0-60 Hz).

I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches
in a separate box would be a lot more convenient. What are typical
specs for a potentiometer for one of these? Something I could pick up
at Radio Shack or do I need to order on line? Under what section of
the manual would you go looking for specs if it's something that
varies by manufacturer and model? I only read enough of the manual to
get my mill up and running so I could play with it. Now that I've had
it for several months, it's time to make improvements.

RWL


Radio Shack pots are garbage. Spend a few bucks and buy something
like this:

http://www.potentiometers.com/seriesRV4.cfm?

then it will last for years. I might even have one laying around
that would work. They are mil spec, and availible surplus. They are
sealed, so you don;t have to wory about dust or metal chips damaging
them.


--
You can't have a sense of humor, if you have no sense!

Ignoramus15363 wrote:

If the control voltage is 10 volts, then a 10k potentiometer would
dissipate 10v*10v/10000ohm = 0.01 watts. You do not need a 2 watt 10k pot.


The two watt pots are made for long life, and have lower wiper noise
that the cheap crap. They were used as volume controls in military
radios and other electronic equipment in WW-II, and are still good.

Buy cheap crap if you want to, but cheap pots are a foolish
investment.


--
You can't have a sense of humor, if you have no sense!

On 2009-09-07, Michael A. Terrell wrote:

[ ... ]

Radio Shack pots are garbage. Spend a few bucks and buy something
like this:

http://www.potentiometers.com/seriesRV4.cfm?

then it will last for years.

Yes -- so that is who took over the Allen Bradley line of
mil-spec pots. Glad to know that quality pots are still made.

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 2009-09-07, Michael A. Terrell wrote:

[ ... ]

Radio Shack pots are garbage. Spend a few bucks and buy something
like this:

http://www.potentiometers.com/seriesRV4.cfm?

then it will last for years.

Yes -- so that is who took over the Allen Bradley line of
mil-spec pots. Glad to know that quality pots are still made.


Buy good pots once, or crap every six months. I prefer quality over
quantity.

They are the only used pots worth salvaging from scrap industrial and
Military electronics.


--
You can't have a sense of humor, if you have no sense!

In article ,
"Michael A. Terrell" wrote:
Buy good pots once, or crap every six months. I prefer quality over
quantity.

They are the only used pots worth salvaging from scrap industrial and
Military electronics.

I'm looking for a source of 5K pots that cover their whole range within
45 degrees of deflection either way from center. i.e. Set so each end to
the wiper is 2.5K and moving the wiper 45 degrees either way will bring
that side to zero. I didn't see anything like that on the URL cited.

Anybody have any ideas where I could buy small quantities?

Meanwhile, still Googling.

John Husvar wrote:

In article ,
"Michael A. Terrell" wrote:
Buy good pots once, or crap every six months. I prefer quality over
quantity.

They are the only used pots worth salvaging from scrap industrial and
Military electronics.

I'm looking for a source of 5K pots that cover their whole range within
45 degrees of deflection either way from center. i.e. Set so each end to
the wiper is 2.5K and moving the wiper 45 degrees either way will bring
that side to zero. I didn't see anything like that on the URL cited.

Anybody have any ideas where I could buy small quantities?

Meanwhile, still Googling.


A standard pot is 270 degrees You could use a three to one gear
drive.


--
You can't have a sense of humor, if you have no sense!