Shopsmith Forums

We not discussing a resistor with DC applied.

Change to AC and phase angles come into play.

Insert a controller and all above becomes irrelevant.


i.e. it is NOT a linear device.

Yes that is all true, the power factor (PF) must be considered in a single phase AC motor. If the motor is other than single phase there are other factors.

DC Motor P=E I
Single phase AC Motor P=E I PF

However, the fact still remains that an motor running on 220V will draw less current than the same motor on 110V.

jsburger wrote:We not discussing a resistor with DC applied.

Change to AC and phase angles come into play.

Insert a controller and all above becomes irrelevant.


i.e. it is NOT a linear device.

Yes that is all true, the power factor (PF) must be considered in a single phase AC motor. If the motor is other than single phase there are other factors.

DC Motor P=E I
Single phase AC Motor P=E I PF

However, the fact still remains that an motor running on 220V will draw less current than the same motor on 110V.

You have missed the point. Blame me for not effectively convincing thee.

We are not dealing with a "motor" here.

We are dealing with a power supply, a controller, and a stepping motor.

The available mechanical power output is dependent upon the available power output of the power supply. The drain upon that power supply is dependent upon the mechanical load and speed.

I have no knowledge of the power supply design details, but presume the slight increase in maximum mechanical output power is the result of greater power supply output available with the increased voltage. There is not a direct relationship between the input voltage and the resultant current at the power cord.

A likely scenario is a full wave bridge and capacitor providing bulk storage. That is likely followed by a switching/oscillator circuit that 'creates' (along with much circuitry) the power source(s) to the controller which then creates the pulses to the motor itself that creates the rotary motion.

BTW Power Factor is the result of the phase angle difference between the voltage and current. It also assumes sinosoidal magnitudes of both.

Again the typical stuff that applies to induction motors ain't relevant with the PP motor 'system'.

JPG wrote:

jsburger wrote:We not discussing a resistor with DC applied.

Change to AC and phase angles come into play.

Insert a controller and all above becomes irrelevant.


i.e. it is NOT a linear device.

Yes that is all true, the power factor (PF) must be considered in a single phase AC motor. If the motor is other than single phase there are other factors.

DC Motor P=E I
Single phase AC Motor P=E I PF

However, the fact still remains that an motor running on 220V will draw less current than the same motor on 110V.

You have missed the point. Blame me for not effectively convincing thee.

We are not dealing with a "motor" here.

We are dealing with a power supply, a controller, and a stepping motor.

The available mechanical power output is dependent upon the available power output of the power supply. The drain upon that power supply is dependent upon the mechanical load and speed.

I have no knowledge of the power supply design details, but presume the slight increase in maximum mechanical output power is the result of greater power supply output available with the increased voltage. There is not a direct relationship between the input voltage and the resultant current at the power cord.

A likely scenario is a full wave bridge and capacitor providing bulk storage. That is likely followed by a switching/oscillator circuit that 'creates' (along with much circuitry) the power source(s) to the controller which then creates the pulses to the motor itself that creates the rotary motion.

BTW Power Factor is the result of the phase angle difference between the voltage and current. It also assumes sinosoidal magnitudes of both.

Again the typical stuff that applies to induction motors ain't relevant with the PP motor 'system'.

Very true! I was thinking conventional AC motor, my bad. The PP (Technatool motor) as far as I can tell is not an AC motor. Variable reluctance motors are actually DC I think. The big breakthrough with Technitool is the digital controller that allows control of the motor very precisely and also allows variable speed (non synchronous)and reverse among other things. Variable reluctance motors are not new. The controllers to take advantage of their properties are fairly new. That is the difference.

A VFD on a 3 phase motor is kind of the same in that the conventional AC motor formulas don't work. The output of the VFD to the motor is a hybrid sinusoidal wave form. It has square wave components so conventional AC motor formulas don't work.

I need to pull up the brain reserves sometime before I reply. Some of this stuff is so far back there that I forget. A jog usually gets me on the right track. Thanks JPG!

Check out this link.

http://nebula.wsimg.com/1783be598260532 ... oworigin=1

Seems like Technitool who developed the DVR motor partnered with SS as their first customer.

When you go to 220v plugs, the male/female they also are amperage rated by the configuration, 20 amp for machinery, 30 amp for a drier, 40 amp for an electric stove/oven. So get the right one.

ERLover wrote:When you go to 220v plugs, the male/female they also are amperage rated by the configuration, 20 amp for machinery, 30 amp for a drier, 40 amp for an electric stove/oven. So get the right one.

And the 120v ones come in two versions - 15A and 20A.

Yes they do JPG!!!

ERLover wrote:Yes they do JPG!!!

FWIW there is also a 120v 20A plug(rarely seen).

Both the 120v and the 240v 20A receptacles will take their respective 15A plug.