?

It interesting thd different ways I have seen for low speeds?
First on AC motors lots of poles you charge the poles for different speeds but very costly motors.

Then was just was belts and or gears.
Variable pitch belts and charge the gear Works but still gears at one was costly too but not bad.

The AC/DC motors usd a Variable transformers. This first lower cost motor setup 1 to w to 1 to 100 speed reduction?

The electronic speed control start with small motors but cost was a lot lower.

The stepper motors in Printers was big change.? In 1970's? they did not need encoders for low cost printers. If skip a a few spaces out of over a hundred thousands you not notice. Next use on low cost CNC equipment. For most part they used two phases motor.
Later I saw mini 3 phase motor but I saw first controls in 1960's but winding your own motors.
Now we know as brushless DC motors . Some maybe two phases I just have seen it .?

Some dates can earlier history on web can be do to the writer error. I know mine maybe off too.?
The 1960's is where lot changes switch from tubes to transitions?

Dave?

Ralph Lehotsky 2:12pm? ?

Yes - it's probably geared down quite a bit for that application, so power is not as important there

?

These right-angle motors with lead screws are used to adjust the seats in cars. ?That there are so many of these being sold on the surplus market means ?to me that they must have been replaced by something better. ? I wonder if they are not all brushless motors now

On Feb 9, 2024, at 3:00?PM, BuffaloJohn <johndurbetaki@...> wrote:

Speaking of that motor from the HSM article - I got an email from? and they are selling that same motor for $10.95 with $6.95 flat rate shipping and they made a brass flange nut for the shaft that is included as well. Here is the link:

On Wed, Feb 7, 2024 at 2:51?PM Bruce J <bruce.desertrat@...> wrote:

?The Jan/Feb 2024 Home Shop Machinist has a cover article about making a power X axis drive for a mini-mill table that uses a 12V car seat motor (American Science and Surplus has been selling them forever; there must be warehouses full of these things??) You could probably modify that little gear motor for that purpose.?

--
Buffalo John

Ralph Lehotsky 2:12pm? ?

Yes - it's probably geared down quite a bit for that application, so power is not as important there

Mike -?

That controller won't put out that much power, it's only a 20A surge.

If it would put out 18A continuously with a 12 VDC motor, that's only 216 watts, not even 1/3 hp.

Even at 24 VDC,? it's less than 500 W,? if you could find a 24 volt motor.

If I upgrade the motor on my mini=lathe, I think I would want at least 0.75 hp, and preferably 1 hp.

ralphie

On Thu, Feb 8, 2024 at 12:27?PM mike allen <animal@...> wrote:

Someone mentioned the car seat motors , these folks have them on sale & also have a controller on sale too

animal

On 2/8/24 10:42 AM, mike allen wrote:

I believe that with PWM nothing happens till 15% duty cycle & limits out at 85% duty cycle . That's in print somewhere out in internet land .

animal

On 2/7/24 10:08 PM, Evan wrote:

I haven't tried using a treadmill motor controller and cannot be specific but hope this is of some help.

Lets start with some calculations from your motor DC specs:
Power = 120 volt x 21 A = 2,520 watts
1 HP = 745 Watts so divide by 745 gives 3.38 HP?
Calculating backwards from 2.5 HP
2.5 x 745 =?1,862.5 Watts
Divide by 120 gives 15.5 amps at full output.
This discrepancy probably means that the motor can handle up to 21A when under load.

When running at its maximum speed of 7000 RPM the armature is acting like a generator creating a 'back-emf' ?or voltage of -120 volts opposing the 120 volt input and that is why it can't run any faster than 7000 RPM. (otherwise it could be a recommended limitation depending on the centrifugal/centripetal forces that the armature can handle without flying apart.)

My Pulse Width Modulator circuit displays amps and volts and I have a tachometer as well. The data from that may help answer your question. Under heavy load the motor slows down, the back EMF decreases at lower RPM and input voltage is able to push through more amps. Eventually as the amperage increases the driver circuit will cut off the power supply to avoid burning out its components.? In addition to that, the PWM circuit tries to maintain power output by increasing average amps as it switches on and off.?

I think the solution is to alter the gearing/pulleys to allow the motor to run at higher RPM.

Note: the potentiometer used in these circuits operates on 0 to 5 or 0-10 volts, so is quite safe. It is still a good idea to have it grounded and/or insulated well.

--
Evan
Lathe: 1955 Boxford Model A with screw cutting gearbox, power feed with several accessories, hand tools and a pillar drill press.
Try my Free Online Gear train Software:
You enter a thread pitch or TPI and it shows you a range of gear trains and gearbox setting to use and even a scale drawing of the gear train.
It also includes calculations for taper turning by the tailstock offset method, and cutting speeds.
It includes the specifications for many thread types eg metric, UNC, BSW, and BA.
Displays drill sizes for tapping threads at any percent thread depth (with full explanations).
My YouTube Channel and Playlist about using an engineers lathe: ?
Project to build a Greek Hero steam engine and measure its power output:?

MPJA is sort of an interesting outfit worth keeping in mind.? They cover a LOT of ground including multiple pages of advertising in a Ham Radio magazine.? All the way to even selling a talking multimeter which isn't really a joke.? You may be in a position difficult to see the meter or want to focus on placing test leads carefully.? And the National Federation of the Blind stocked these at one time.

Charles E. "Chuck" Kinzer

On Thursday, February 8, 2024 at 11:27:33 AM PST, mike allen <animal@...> wrote:

Someone mentioned the car seat motors , these folks have them on sale & also have a controller on sale too

animal

On 2/8/24 10:42 AM, mike allen wrote:

I believe that with PWM nothing happens till 15% duty cycle & limits out at 85% duty cycle . That's in print somewhere out in internet land .

animal

On 2/7/24 10:08 PM, Evan wrote:

I haven't tried using a treadmill motor controller and cannot be specific but hope this is of some help.

Lets start with some calculations from your motor DC specs:
Power = 120 volt x 21 A = 2,520 watts
1 HP = 745 Watts so divide by 745 gives 3.38 HP?
Calculating backwards from 2.5 HP
2.5 x 745 =?1,862.5 Watts
Divide by 120 gives 15.5 amps at full output.
This discrepancy probably means that the motor can handle up to 21A when under load.

When running at its maximum speed of 7000 RPM the armature is acting like a generator creating a 'back-emf' ?or voltage of -120 volts opposing the 120 volt input and that is why it can't run any faster than 7000 RPM. (otherwise it could be a recommended limitation depending on the centrifugal/centripetal forces that the armature can handle without flying apart.)

My Pulse Width Modulator circuit displays amps and volts and I have a tachometer as well. The data from that may help answer your question. Under heavy load the motor slows down, the back EMF decreases at lower RPM and input voltage is able to push through more amps. Eventually as the amperage increases the driver circuit will cut off the power supply to avoid burning out its components. ?In addition to that, the PWM circuit tries to maintain power output by increasing average amps as it switches on and off.?

I think the solution is to alter the gearing/pulleys to allow the motor to run at higher RPM.

Note: the potentiometer used in these circuits operates on 0 to 5 or 0-10 volts, so is quite safe. It is still a good idea to have it grounded and/or insulated well.

--
Evan
Lathe: 1955 Boxford Model A with screw cutting gearbox, power feed with several accessories, hand tools and a pillar drill press.
Try my Free Online Gear train Software:
You enter a thread pitch or TPI and it shows you a range of gear trains and gearbox setting to use and even a scale drawing of the gear train.
It also includes calculations for taper turning by the tailstock offset method, and cutting speeds.
It includes the specifications for many thread types eg metric, UNC, BSW, and BA.
Displays drill sizes for tapping threads at any percent thread depth (with full explanations).
My YouTube Channel and Playlist about using an engineers lathe: ?
Project to build a Greek Hero steam engine and measure its power output:?

I believe that with PWM nothing happens till 15% duty cycle & limits out at 85% duty cycle . That's in print somewhere out in internet land .

animal

On 2/7/24 10:08 PM, Evan wrote:

I haven't tried using a treadmill motor controller and cannot be specific but hope this is of some help.

Lets start with some calculations from your motor DC specs:
Power = 120 volt x 21 A = 2,520 watts
1 HP = 745 Watts so divide by 745 gives 3.38 HP?
Calculating backwards from 2.5 HP
2.5 x 745 =?1,862.5 Watts
Divide by 120 gives 15.5 amps at full output.
This discrepancy probably means that the motor can handle up to 21A when under load.

When running at its maximum speed of 7000 RPM the armature is acting like a generator creating a 'back-emf' ?or voltage of -120 volts opposing the 120 volt input and that is why it can't run any faster than 7000 RPM. (otherwise it could be a recommended limitation depending on the centrifugal/centripetal forces that the armature can handle without flying apart.)

My Pulse Width Modulator circuit displays amps and volts and I have a tachometer as well. The data from that may help answer your question. Under heavy load the motor slows down, the back EMF decreases at lower RPM and input voltage is able to push through more amps. Eventually as the amperage increases the driver circuit will cut off the power supply to avoid burning out its components. ?In addition to that, the PWM circuit tries to maintain power output by increasing average amps as it switches on and off.?

I think the solution is to alter the gearing/pulleys to allow the motor to run at higher RPM.

Note: the potentiometer used in these circuits operates on 0 to 5 or 0-10 volts, so is quite safe. It is still a good idea to have it grounded and/or insulated well.

--
Evan
Lathe: 1955 Boxford Model A with screw cutting gearbox, power feed with several accessories, hand tools and a pillar drill press.
Try my Free Online Gear train Software:
You enter a thread pitch or TPI and it shows you a range of gear trains and gearbox setting to use and even a scale drawing of the gear train.
It also includes calculations for taper turning by the tailstock offset method, and cutting speeds.
It includes the specifications for many thread types eg metric, UNC, BSW, and BA.
Displays drill sizes for tapping threads at any percent thread depth (with full explanations).
My YouTube Channel and Playlist about using an engineers lathe: ?
Project to build a Greek Hero steam engine and measure its power output:?

I believe that with PWM nothing happens till 15% duty cycle & limits out at 85% duty cycle . That's in print somewhere out in internet land .

animal

On 2/7/24 10:08 PM, Evan wrote:

I haven't tried using a treadmill motor controller and cannot be specific but hope this is of some help.

Lets start with some calculations from your motor DC specs:
Power = 120 volt x 21 A = 2,520 watts
1 HP = 745 Watts so divide by 745 gives 3.38 HP?
Calculating backwards from 2.5 HP
2.5 x 745 =?1,862.5 Watts
Divide by 120 gives 15.5 amps at full output.
This discrepancy probably means that the motor can handle up to 21A when under load.

When running at its maximum speed of 7000 RPM the armature is acting like a generator creating a 'back-emf' ?or voltage of -120 volts opposing the 120 volt input and that is why it can't run any faster than 7000 RPM. (otherwise it could be a recommended limitation depending on the centrifugal/centripetal forces that the armature can handle without flying apart.)

My Pulse Width Modulator circuit displays amps and volts and I have a tachometer as well. The data from that may help answer your question. Under heavy load the motor slows down, the back EMF decreases at lower RPM and input voltage is able to push through more amps. Eventually as the amperage increases the driver circuit will cut off the power supply to avoid burning out its components. ?In addition to that, the PWM circuit tries to maintain power output by increasing average amps as it switches on and off.?

I think the solution is to alter the gearing/pulleys to allow the motor to run at higher RPM.

Note: the potentiometer used in these circuits operates on 0 to 5 or 0-10 volts, so is quite safe. It is still a good idea to have it grounded and/or insulated well.

--
Evan
Lathe: 1955 Boxford Model A with screw cutting gearbox, power feed with several accessories, hand tools and a pillar drill press.
Try my Free Online Gear train Software:
You enter a thread pitch or TPI and it shows you a range of gear trains and gearbox setting to use and even a scale drawing of the gear train.
It also includes calculations for taper turning by the tailstock offset method, and cutting speeds.
It includes the specifications for many thread types eg metric, UNC, BSW, and BA.
Displays drill sizes for tapping threads at any percent thread depth (with full explanations).
My YouTube Channel and Playlist about using an engineers lathe: ?
Project to build a Greek Hero steam engine and measure its power output:?