Can anyone point me to a web resource that lays out the basics of DC
motor controlling or possibly put down the bullet points of same?

I would like to convert my drill press to DC and after reviewing the
myriad of options on ePay, decided I need experienced help.

I would like to buy surplus/used parts if at all possible and need some
guildlines as to what to look for such as DC field voltage of motor,
typical controller types used, pitfalls, etc.

If anyone could comment on what they did when they converted their
machine(s) it would be greatly appreciated.

On 12 Feb 2006 07:56:53 -0800, "mechanized_robot"
wrote:

Can anyone point me to a web resource that lays out the basics of DC
motor controlling or possibly put down the bullet points of same?

First you need to understand the motors themselves.

http://www.electricmotors.machinedesign.com/

There is a ton of motor control stuff at
http://www.microchip.com/stellent/st...83&pageId=6 4

This is primarily aimed at use of Microcontrollers for motor control,
but theres some good basic stuff, like drive cctry, there as well.

I would like to convert my drill press to DC and after reviewing the
myriad of options on ePay, decided I need experienced help.

I would like to buy surplus/used parts if at all possible and need some
guildlines as to what to look for such as DC field voltage of motor,
typical controller types used, pitfalls, etc.

Just look for motors that have the speed, torque and/or power you
think you need. Matters of field voltage (if not PM motors) can be
dealt with. Understand that DC motors do have a maximum torque
limited by max current. Reducing speed with pulleys or gears also
increases delivered torque, but if speed control is done electrically
then the motor must deliver the full load torque even at reduced.
speeds.

Best speed control is obtained with tachometer feedback. Some motors
have built-in tachs. An external tach or encoder can also be used.

If anyone could comment on what they did when they converted their
machine(s) it would be greatly appreciated.

DC motors work very well on DP's. The size of the DP, whether is has single
or double pulley reduction and the material you want to drill normally are
all considerations. If it's a large DP, then I'd go with something like
Surplus Centers GE 1.25hp 104VDC motor. I have one on an old Hercules DP
that was used to drill 1.5" holes in tool steel. With a small DP, a .25 or
..50 hp motor might be plenty. With double belt reduction (center step
down/up pulley) Smaller hp will do more. If you're old school, you can use
a Variac and a bridge rectifier to run it. You will be adjusting while
running when drilling because you're varying current and voltage at the same
time. For better results, go to a solid state controller (KB, Minaric,
etc.) and your spindle will maintain speed under load as current is
maintained and voltage (pulse width) is varied (simplistic description).
Some controllers have integrated reverse switching either by switches,
relays or regenerative circuits. This is helpful/required if tapping. With
the Variac supply, a reversing switch can easily be installed. The same
with the solid state type, but they are a bit more sensitive to reverse
surges (reversing motor while at speed). In most cases, one should stop the
spindle before reversing direction. The regenerative type is the exception.
A resistor can be used to apply braking for more effecient control. BTW,
beware of small motors with high rated hp as this sometimes refers to
"developed hp" due to high speed. Mass is usually a good thing.
Basically, the above refers to PM (permanent magnet) motors. Shunt wound
motors are effectively similar, but with a required field power supply
needed. Most solid state controllers have this available at full or half
supply voltage. A Variac can be tapped at the correct point for this. With
two Variac supplies, interesting results can be had by varying the field
supply. This method was used on old DC systems, ie. Monarch EE. The higher
field voltage suppresses motor rpm but can add torque at low speeds. Very
low field voltage can/will result in VERY high motor speeds and possible
shrapnel.
Respectfully,
Ron Moore

"Ignoramus8228" wrote in message
...
On 12 Feb 2006 07:56:53 -0800, mechanized_robot
wrote:
Can anyone point me to a web resource that lays out the basics of DC
motor controlling or possibly put down the bullet points of same?

I would like to convert my drill press to DC and after reviewing the
myriad of options on ePay, decided I need experienced help.

I would like to buy surplus/used parts if at all possible and need some
guildlines as to what to look for such as DC field voltage of motor,
typical controller types used, pitfalls, etc.

If anyone could comment on what they did when they converted their
machine(s) it would be greatly appreciated.


If/when you learn anything, please let me know, I am very interested
in converting a DP to DC.

i

Many thanks to Ron & Don!

This is exactly the primer I was looking for.

I installed a surplus center DC treadmill motor and controler on my drill
press about 5 years ago and it is a wonderful thing Thanks to Don and
others for help with modifying the controler to work better as a tool motor.
The treadmill controller had a slow ramp up and would only start at zero and
you had to bring the speed up with a pot. This motor is no longer available
from surplus center but it is rated at 2HP. The controler limits the
current to 10 Amps so the actual HP is much less ~3/4hp. It is a series
wound motor with a tach feedback to the control to maintain the set speed
under variable loads. It has a max of 6KRPM and I set it on the slowest
belt speed on the drillpress. I get very useful power from about 100 to
1000 spindle RPM without moving belts. The motor is biased (brushes offset)
to run in one direction but is reversable and seems to do ok with that at
slightly reduced power if you only use the reverse occasionally. You should
be able to source a motor and controler from a used treadmill. I put one on
the drill press, one on a 6"Atlas and one on a wood lathe. All are still
quite happy.
HTH
Glenn
"mechanized_robot" wrote in message
oups.com...
Can anyone point me to a web resource that lays out the basics of DC
motor controlling or possibly put down the bullet points of same?

I would like to convert my drill press to DC and after reviewing the
myriad of options on ePay, decided I need experienced help.

I would like to buy surplus/used parts if at all possible and need some
guildlines as to what to look for such as DC field voltage of motor,
typical controller types used, pitfalls, etc.

If anyone could comment on what they did when they converted their
machine(s) it would be greatly appreciated.

On Sun, 12 Feb 2006 10:49:22 -0800, "Glenn"
wrote:

I installed a surplus center DC treadmill motor and controler on my drill
press about 5 years ago and it is a wonderful thing Thanks to Don and
others for help with modifying the controler to work better as a tool motor.
The treadmill controller had a slow ramp up and would only start at zero and
you had to bring the speed up with a pot. This motor is no longer available
from surplus center but it is rated at 2HP.

They're still around, though. I see them at Ax Man Surplus in
Fridley, MN.
http://www.ax-man.com/

Don Foreman wrote:

There is a ton of motor control stuff at
http://www.microchip.com

not to forget ST with their nice little 30A 40V full H-bridges.


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO - YADRO - Eigenbau-Digitalanzeige

Glenn wrote:
.... You should
be able to source a motor and controler from a used treadmill. ...

"Buyer beware". Not all treadmill motors are equal. I have scavenged a
few from the dump and one in particular was very surprising in its
performance: with it running at full speed (6K rpm), I was able to bring
it to a stop by putting my bare hand on the 10" flywheel!! This was
supposedly a 1 1/2 hp (+-) motor. Yeah, right. I was very glad that I
hadn't paid anything for it, or had invested any time installing it on a
machine. POS for sure.

Bob

On Sun, 12 Feb 2006 20:53:18 -0500, Bob Engelhardt
wrote:

Glenn wrote:
... You should
be able to source a motor and controler from a used treadmill. ...

"Buyer beware". Not all treadmill motors are equal. I have scavenged a
few from the dump and one in particular was very surprising in its
performance: with it running at full speed (6K rpm), I was able to bring
it to a stop by putting my bare hand on the 10" flywheel!! This was
supposedly a 1 1/2 hp (+-) motor. Yeah, right. I was very glad that I
hadn't paid anything for it, or had invested any time installing it on a
machine. POS for sure.

Why would one grab a flywheel spinning at 6k rpm with their bare hand?

Snarl

wrote:
Why would one grab a flywheel spinning at 6k rpm with their bare hand?

I said that I put my hand on it, I didn't say that I grabbed it. An
open palm, on the circumference, with gradually increasing pressure. I
did it to see how strong it was, as I was beginning to have my doubts.
Well founded, it turned out.

Bob

On Sun, 12 Feb 2006 20:53:18 -0500, Bob Engelhardt
wrote:

Glenn wrote:
... You should
be able to source a motor and controler from a used treadmill. ...

"Buyer beware". Not all treadmill motors are equal. I have scavenged a
few from the dump and one in particular was very surprising in its
performance: with it running at full speed (6K rpm), I was able to bring
it to a stop by putting my bare hand on the 10" flywheel!! This was
supposedly a 1 1/2 hp (+-) motor. Yeah, right. I was very glad that I
hadn't paid anything for it, or had invested any time installing it on a
machine. POS for sure.

Bob

Those motors are rated in Sears HP. 3/4 hp is closer to right.

--If you're lucky enough to live in the SF Bay Area the Crucible has
just released the schedule of Spring classes. Included is one on how to
build a DC power supply. I'll bet they could tell you a bunch about the
right stuff you'll need to do the job right..

--
"Steamboat Ed" Haas : Woohoo! Cheney sez
Hacking the Trailing Edge! : lawyer season's open!
http://www.nmpproducts.com/intro.htm
---Decks a-wash in a sea of words---

On Sun, 12 Feb 2006 20:53:18 -0500, Bob Engelhardt
wrote:

Glenn wrote:
... You should
be able to source a motor and controler from a used treadmill. ...

"Buyer beware". Not all treadmill motors are equal. I have scavenged a
few from the dump and one in particular was very surprising in its
performance: with it running at full speed (6K rpm), I was able to bring
it to a stop by putting my bare hand on the 10" flywheel!! This was
supposedly a 1 1/2 hp (+-) motor. Yeah, right. I was very glad that I
hadn't paid anything for it, or had invested any time installing it on a
machine. POS for sure.

Bob

Stuff found at the dump sometimes doesn't work as well as unused
surplus. The surplus treadmill motor controllers are notorious for
being unreliable but the motors themselves seem to work OK.

Unused surplus treadmill motors run about $40. AxMan in Fridley MN
had 6 of them yesterday.

On Sun, 12 Feb 2006 23:31:52 -0500, Bob Engelhardt
wrote:

wrote:
Why would one grab a flywheel spinning at 6k rpm with their bare hand?

I said that I put my hand on it, I didn't say that I grabbed it.

My bad, saw a conclusion and jumped on it g.

An
open palm, on the circumference, with gradually increasing pressure. I
did it to see how strong it was, as I was beginning to have my doubts.
Well founded, it turned out.

Indeed. A test like that wouldn't ever have occured to me shrug.

Snarl

On Mon, 13 Feb 2006 11:28:14 -0600, Don Foreman
wrote:

On Sun, 12 Feb 2006 20:53:18 -0500, Bob Engelhardt
wrote:

Glenn wrote:
... You should
be able to source a motor and controler from a used treadmill. ...

"Buyer beware". Not all treadmill motors are equal. I have scavenged a
few from the dump and one in particular was very surprising in its
performance: with it running at full speed (6K rpm), I was able to bring
it to a stop by putting my bare hand on the 10" flywheel!! This was
supposedly a 1 1/2 hp (+-) motor. Yeah, right. I was very glad that I
hadn't paid anything for it, or had invested any time installing it on a
machine. POS for sure.

Bob

Stuff found at the dump sometimes doesn't work as well as unused
surplus. The surplus treadmill motor controllers are notorious for
being unreliable but the motors themselves seem to work OK.

Unused surplus treadmill motors run about $40. AxMan in Fridley MN
had 6 of them yesterday.

Ive got 20 New in the box, 110vt DC treadmill motors. Any offers?

Gunner



"A prudent man foresees the difficulties ahead and prepares for them;
the simpleton goes blindly on and suffers the consequences."
- Proverbs 22:3

Gunner - where are you located?

On Mon, 13 Feb 2006 19:56:02 GMT, Gunner
wrote:

On Mon, 13 Feb 2006 11:28:14 -0600, Don Foreman
wrote:

On Sun, 12 Feb 2006 20:53:18 -0500, Bob Engelhardt
wrote:

Glenn wrote:
... You should
be able to source a motor and controler from a used treadmill. ...

"Buyer beware". Not all treadmill motors are equal. I have scavenged a
few from the dump and one in particular was very surprising in its
performance: with it running at full speed (6K rpm), I was able to bring
it to a stop by putting my bare hand on the 10" flywheel!! This was
supposedly a 1 1/2 hp (+-) motor. Yeah, right. I was very glad that I
hadn't paid anything for it, or had invested any time installing it on a
machine. POS for sure.

Bob

Stuff found at the dump sometimes doesn't work as well as unused
surplus. The surplus treadmill motor controllers are notorious for
being unreliable but the motors themselves seem to work OK.

Unused surplus treadmill motors run about $40. AxMan in Fridley MN
had 6 of them yesterday.

Ive got 20 New in the box, 110vt DC treadmill motors. Any offers?

Gunner

Are they DCPM (permanent magnet) or wound field motors? How to tell
if they're not marked: put a DC voltmeter on the terminals and spin
the shaft by hand. If the meter jumps, they're DCPM motors.

On 13 Feb 2006 14:44:33 -0800, "mechanized_robot"
wrote:

Gunner - where are you located?


Near Bakersfield California

Gunner



"A prudent man foresees the difficulties ahead and prepares for them;
the simpleton goes blindly on and suffers the consequences."
- Proverbs 22:3

On Mon, 13 Feb 2006 17:07:14 -0600, Don Foreman
wrote:

On Mon, 13 Feb 2006 19:56:02 GMT, Gunner
wrote:

On Mon, 13 Feb 2006 11:28:14 -0600, Don Foreman
wrote:

On Sun, 12 Feb 2006 20:53:18 -0500, Bob Engelhardt
wrote:

Glenn wrote:
... You should
be able to source a motor and controler from a used treadmill. ...

"Buyer beware". Not all treadmill motors are equal. I have scavenged a
few from the dump and one in particular was very surprising in its
performance: with it running at full speed (6K rpm), I was able to bring
it to a stop by putting my bare hand on the 10" flywheel!! This was
supposedly a 1 1/2 hp (+-) motor. Yeah, right. I was very glad that I
hadn't paid anything for it, or had invested any time installing it on a
machine. POS for sure.

Bob

Stuff found at the dump sometimes doesn't work as well as unused
surplus. The surplus treadmill motor controllers are notorious for
being unreliable but the motors themselves seem to work OK.

Unused surplus treadmill motors run about $40. AxMan in Fridley MN
had 6 of them yesterday.

Ive got 20 New in the box, 110vt DC treadmill motors. Any offers?

Gunner

Are they DCPM (permanent magnet) or wound field motors? How to tell
if they're not marked: put a DC voltmeter on the terminals and spin
the shaft by hand. If the meter jumps, they're DCPM motors.

Ill check. They only have two leads

Gunner



"A prudent man foresees the difficulties ahead and prepares for them;
the simpleton goes blindly on and suffers the consequences."
- Proverbs 22:3

On 13 Feb 2006 23:59:25 GMT, Ignoramus1130
wrote:

On Mon, 13 Feb 2006 19:56:02 GMT, Gunner wrote:
On Mon, 13 Feb 2006 11:28:14 -0600, Don Foreman
wrote:

On Sun, 12 Feb 2006 20:53:18 -0500, Bob Engelhardt
wrote:

Glenn wrote:
... You should
be able to source a motor and controler from a used treadmill. ...

"Buyer beware". Not all treadmill motors are equal. I have scavenged a
few from the dump and one in particular was very surprising in its
performance: with it running at full speed (6K rpm), I was able to bring
it to a stop by putting my bare hand on the 10" flywheel!! This was
supposedly a 1 1/2 hp (+-) motor. Yeah, right. I was very glad that I
hadn't paid anything for it, or had invested any time installing it on a
machine. POS for sure.

Bob

Stuff found at the dump sometimes doesn't work as well as unused
surplus. The surplus treadmill motor controllers are notorious for
being unreliable but the motors themselves seem to work OK.

Unused surplus treadmill motors run about $40. AxMan in Fridley MN
had 6 of them yesterday.

Ive got 20 New in the box, 110vt DC treadmill motors. Any offers?

I may be interested in buying one, got nameplate info on them?

i

Ill post the info. However...I refuse to sell you a motor.

You may however..pay the shipping on one.

Gunner



"A prudent man foresees the difficulties ahead and prepares for them;
the simpleton goes blindly on and suffers the consequences."
- Proverbs 22:3

The other test is to short the motor leads. If that applies the brakes to
the motor, the you have a permanent magnet DC motor. I have found that the
more braking you get this way, the more torque the motor "seems" to have,
especially at low speed.
Respectfully,
Ron Moore



Are they DCPM (permanent magnet) or wound field motors? How to tell
if they're not marked: put a DC voltmeter on the terminals and spin
the shaft by hand. If the meter jumps, they're DCPM motors.

Ill check. They only have two leads

Gunner



"A prudent man foresees the difficulties ahead and prepares for them;
the simpleton goes blindly on and suffers the consequences."
- Proverbs 22:3

"Ron Moore" wrote in message
news:JenIf.2049$Tf3.1926@dukeread09...
The other test is to short the motor leads. If that applies the brakes to
the motor, the you have a permanent magnet DC motor. I have found that
the more braking you get this way, the more torque the motor "seems" to
have, especially at low speed.
Respectfully,
Ron Moore

I scrounged a pair of reel take-up motors from a fairly modern 9-track
computer tape drive. Their efficiency and magnetic coupling was so good
that two motors connected to one another worked almost perfectly
syncronously. If you turned one shaft - even slowly, by hand - the other
motor would track with virtually no perceptable "slip".

LLoyd