110 volt DC motor where was it used

[skipskip]

I have an Eastman fabric cutter with a 110 volt DC motor.

where would 110v DC have used? factory? non US country?

kodah by Skip Albright, on Flickr

 

[slip knot]

My welding machine has a 110v DC plug. run my grinder with it while welding. Evidently 110 dc wasn't too uncommon.

 

[The Cobbler]

apparently in the early days there was a battle to see if AC or DC power would be the choice . AC won

https://energy.gov/articles/war-currents-ac-vs-dc-power

 

[wuck]

apparently in the early days there was a battle to see if AC or DC power would be the choice . AC won

https://energy.gov/articles/war-currents-ac-vs-dc-power

Some places are slower than others to adopt:

DC power distribution in San Francisco

Con Edison shut off DC in 2007

As the article the Cobbler pointed out, a new debate is rising, the DC powered house
--
Pat

 

[teamextreme]

125VDC is common in generating facilities such as dams. At least at the 2 I've done work at.

 

[dogdog]

is it a 3 phase DC? like it mentioned on the nameplate? Something I have noticed on some ebay motors I am looking at lately.... just curious if this is like the BLDC thing.

 

[dscheidt]

is it a 3 phase DC? like it mentioned on the nameplate? Something I have noticed on some ebay motors I am looking at lately.... just curious if this is like the BLDC thing.

three phase DC doesn't make any sense.

 

[manwithtools]

125VDC is common in generating facilities such as dams. At least at the 2 I've done work at.

125VDC is commonly used for control voltage in low, medium and high voltage switchgear - used in power generation and distribution. The reason for DC is to allow battery backup for the control system so they can still operate the switchgear in the event of a power outage - kind of important if you want to get the power turned back on, or remove a load from the system before restoring power.

This 125VDC is generally not used anywhere else in industry, commercial or residential that I am aware of.

 

[manwithtools]

is it a 3 phase DC? like it mentioned on the nameplate? Something I have noticed on some ebay motors I am looking at lately.... just curious if this is like the BLDC thing.

That motor is likely far to old to have used a Brushless DC technology. I'll bet it came from the days before AC took over as the dominate power delivery system

 

[American Locomotive]

It would have been used in homes and factories. The first electric service in the U.S. was 110v DC. AC eventually won out starting at the turn of the century. However DC was fairly common into the 1920s and 30s - especially some areas of New York City and rural communities.

 

[spudley]

Just put a new control board in a treadmill and noticed it has a 120 VDC motor, so looks like they are used.

 

[manwithtools]

Just put a new control board in a treadmill and noticed it has a 120 VDC motor, so looks like they are used.

Permanent magnet DC motors are used in devices that need to have variable speed at a relatively low cost. You'l notice that your treadmill operates on 120VAC input, the controller you replaced converts AC to DC and controls the speed of the motor.

The OP's motor likely has no controller and is not variable speed, it's designed to be feed a direct DC source. It could be supplied from a DC motor controller, but that's not the way it was originally intended.

 

[wyliesdiesels]

No such thing as 3 phase DC.

Theres 3 wire DC but its not polyphase.

 

[manwithtools]

No such thing as 3 phase DC.

Theres 3 wire DC but its not polyphase.

Wylies, I thought the same thing, but actually there is. It's produced by hall effect sensors and a relatively sophisticated controller. There are sensorless implementations as well. Interesting concept.

https://www.digikey.com/en/articles/techzone/2013/mar/an-introduction-to-brushless-dc-motor-control

 

[wyliesdiesels]

Wylies, I thought the same thing, but actually there is. It's produced by hall effect sensors and a relatively sophisticated controller. Interesting concept.

https://www.digikey.com/en/articles/techzone/2013/mar/an-introduction-to-brushless-dc-motor-control

That looks like its for digital motors.

Heres a discussion on the topic:

"Phase is a property of cyclically varying things like AC voltages. DC is not variant, but constant with respect to time.

The concept of phase is meaningless for DC."

https://www.quora.com/Does-a-DC-current-have-a-3-phase-current

 

[American Locomotive]

Wylies, I thought the same thing, but actually there is. It's produced by hall effect sensors and a relatively sophisticated controller. Interesting concept.

https://www.digikey.com/en/articles/techzone/2013/mar/an-introduction-to-brushless-dc-motor-control

There is no such thing as "3 phase DC". The term "Brushless DC Motor" is really a misnomer. BLDC motors are actually 3-phase permanent-magnet synchronous AC motors. However their controllers often run on a DC input, and many times the controller is integrated right into the motor housing itself, so the motor only has a DC input.

The only thing "DC" about BLDC motors is the power that gets input into the controller. The motor itself is AC.

 

[manwithtools]

That looks like its for digital motors.

Heres a discussion on the topic:

"Phase is a property of cyclically varying things like AC voltages. DC is not variant, but constant with respect to time.

The concept of phase is meaningless for DC."

https://www.quora.com/Does-a-DC-current-have-a-3-phase-current

Study this a bit more, it's very much like a typical AC three phase.

https://www.digikey.com/en/articles/techzone/2013/mar/an-introduction-to-brushless-dc-motor-control

 

[American Locomotive]

Study this a bit more, it's very much like a typical AC three phase.

It's very much typical AC three phase, because it IS 3-phase AC! BLDC motors are synchronous AC motors. It is not "3 phase DC".

 

[manwithtools]

It's very much typical AC three phase, because it IS 3-phase AC! BLDC motors are synchronous AC motors. It is not "3 phase DC".

So, the output from a VFD is AC?

 

[wyliesdiesels]

So, the output from a VFD is AC?

Yes it is.

Theyre used for controlling the speed of 3 phase AC motors.

 

[manwithtools]

Yes it is.

Theyre used for controlling the speed of 3 phase AC motors.

No, it's not, it is highly modulated DC.

 

[American Locomotive]

So, the output from a VFD is AC?

Yes it is, actually. If the voltage at any point crosses the the "0" point and heads "negative" relative to 0, it's "alternating". A perfect square wave alternating between 12 and -12v is still AC current.

Look at a VFD output, it crosses the 0 point just like mains AC does. If you put a line-reactor filter on the output of a DC, you'll get an output waveform identical to that of mains AC. You cold even get true smooth AC without the need of a filter out of a VFD by running the transistors in analog mode, but you'd have a ton of waste heat.

No, it's not, it is highly modulated DC.

That's a nonsensical statement. That's like saying a power plant's generator is just "modulating DC" since the main rotor cuts through a magnetic field created by DC current.

 

[manwithtools]

It's DC that is switched to create "simulated" AC and you know it. You can't twist the words to end up with any other outcome. It's not pure sinusoidal (although newer drives come very close).

Your interpretation of what is AC is quite contrary to the rest of the electrical world.

Here's a cheap and dirty explanation: https://www.vfds.com/blog/what-is-a-vfd

My statement is not "nonsensical".

 

[manwithtools]

Yes it is, actually. If the voltage at any point crosses the the "0" point and heads "negative" relative to 0, it's "alternating". A perfect square wave alternating between 12 and -12v is still AC current.

Look at a VFD output, it crosses the 0 point just like mains AC does. If you put a line-reactor filter on the output of a DC, you'll get an output waveform identical to that of mains AC. You cold even get true smooth AC without the need of a filter out of a VFD by running the transistors in analog mode, but you'd have a ton of waste heat.

That's a nonsensical statement. That's like saying a power plant's generator is just "modulating DC" since the main rotor cuts through a magnetic field created by DC current.

Who asked about putting a line reactor on the output of a VFD to create waveform closer to true AC? I asked what the TRUE output of an VFD was - it's not pure sinusoidal AC and never has been..

My point is (even if a little obscure for some readers) VFD's technically produce "three phase DC".

 

[wyliesdiesels]

Lol.

The AC input is converted to DC then an inverter converts it back to AC.

Apparently you didnt read the article you yourself referenced.

 

[American Locomotive]

Your interpretation of what is AC is quite contrary to the rest of the electrical world.

My interpretation matches up EXACTLY with the "rest of the electrical world". When the voltage "crosses" the 0v threshold and goes negative, it's changing polarity or "alternating".

Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction.

Either as a voltage switching polarity or as a current switching direction back and forth, this “kind” of electricity is known as Alternating Current (AC):

The voltage in AC circuits also periodically reverses because the current changes direction.

AC is short for alternating current. This means that the direction of current flowing in a circuit is constantly being reversed back and forth.

An AC waveform can be sinusoidal, square, or sawtooth-shaped. Some AC waveforms are irregular or complicated.

This is an AC waveform!

These are all AC waveforms!

See the line cutting through the middle of each waveform? That's the 0v line. The voltage crossing that line means it's switching polarity from positive to negative. It's alternating polarity.

Here's an actual output waveform diagram from a VFD. The red indicates a "positive" polarity", the blue indicates a "negative" polarity. Note how half is positive, and half is negative? It's alternating. It's AC current. Note the super-imposed sinewave? That's representing the average voltage as a result of the VFD's PWM frequency modulation.

 

[manwithtools]

Lol.

The AC input is converted to DC then an inverter converts it back to AC.

Apparently you didnt read the article you yourself referenced.

I've read plenty of the articles and plenty of the manuals and been through countless courses. It's not true AC by even the farthest stretch of the imagination. Motors don't care, there reaction is very similar to true AC, but its chopped DC that is output from a FVD. It's a "simulated" AC, it's a square waveform, not sinusoidal AC. This is true of any "inverter"

 

[American Locomotive]

I've read plenty of the articles and plenty of the manuals and been through countless courses. It's not true AC by even the farthest stretch of the imagination. Motors don't care, there reaction is very similar to true AC, but its chopped DC that is output from a FVD. It's a "simulated" AC, it's a square waveform, not sinusoidal AC. This is true of any "inverter"

Read post 26. There is a misunderstanding here of exactly what "AC" means. "AC" doesn't mean a true and perfect sinewave. It just means a current that alternates polarity. It can be a square, sawtooth, triangle, rollercoaster, knife-edge, lightning bolt, cloverleaf-interchange, whatever wave. As long as it's switching polarity, it's AC.

This is pure DC, notice how it doesn't change voltage and it stays one polarity the entire time:

This is a DC signal being modulated by an AC signal. Notice that while it's going up and down in voltage, it's not changing polarity. It's still DC.

This on the hand is a pure AC signal, even though it's a square wave. Exactly half the signal is one polarity, and half is another. There is no DC component. This is sort of output you get from a BLDC motor driver. VFDs take this a step further and modulate the pulses to approximate a sinewave.

 

[manwithtools]

My interpretation matches up EXACTLY with the "rest of the electrical world". When the voltage "crosses" the 0v threshold and goes negative, it's changing polarity or "alternating".






This is an AC waveform!

These are all AC waveforms!

See the line cutting through the middle of each waveform? That's the 0v line. The voltage crossing that line means it's switching polarity from positive to negative. It's alternating polarity.

Alternating polarity, that's just about what this thread has become.

OP, sorry for the thread derailment.

Merican Loco, what waveform is considered an actual sine AC waveform, the kind that would come from your utility?

Let's quote the rest of your internet source:

"Some AC waveforms are irregular or complicated. Square or sawtooth waves are produced by certain types of electronic oscillators, and by a low-end UPS (uninterruptible power supply) when it is operating from its battery. Irregular AC waves are produced by audio amplifiers that deal with analog voice signals and/or music.

The sine wave is unique in that it represents energy entirely concentrated at a single frequency. An ideal, unmodulated wireless signal has a sine waveform, with a frequency usually measured in megahertz (MHz) or gigahertz (GHz). Household utility current has a sine waveform with a frequency of 60 Hz in most countries including the United States, although in some countries it is 50 Hz."

 

[manwithtools]

From the Interwebs:

"Notice that the output from the VFD is a “rectangular” wave form. VFD’s do not produce a sinusoidal output. This rectangular waveform would not be a good choice for a general purpose distribution system, but is perfectly adequate for a motor."

 

[manwithtools]

Back to the OP's question.

Your motor would not have been run from today's AC power sources without a DC controller, it also would not have been run from a VFD (they are for AC motors).

It would have most likely been run in a factory that was supplied with 110 volt DC power many years ago (100 +) when DC was still the power distribution of choice.

 

[wyliesdiesels]

Manwithtools- with your logic about sinewaves, battery backups/UPSs that do step approximated sine wave output, would be outputting DC. But they dont.

 

[manwithtools]

Manwithtools- with your logic about sinewaves, battery backups/UPSs that do step approximated sine wave output, would be outputting DC. But they dont.

But they do, they use IGPT's to pulse DC to approximate AC waveforms. This is getting to be a lifeless equine discusion where a couple of folks want to have the last word.

http://myelectrical.com/notes/entryid/250/how-d-c-to-a-c-inverters-work

 

[American Locomotive]

"Some AC waveforms are irregular or complicated. Square or sawtooth waves are produced by certain types of electronic oscillators, and by a low-end UPS (uninterruptible power supply) when it is operating from its battery. Irregular AC waves are produced by audio amplifiers that deal with analog voice signals and/or music.

The sine wave is unique in that it represents energy entirely concentrated at a single frequency. An ideal, unmodulated wireless signal has a sine waveform, with a frequency usually measured in megahertz (MHz) or gigahertz (GHz). Household utility current has a sine waveform with a frequency of 60 Hz in most countries including the United States, although in some countries it is 50 Hz."

From the Interwebs:
"Notice that the output from the VFD is a “rectangular” wave form. VFD’s do not produce a sinusoidal output. This rectangular waveform would not be a good choice for a general purpose distribution system, but is perfectly adequate for a motor."

Okay and what in the world is your point? You're creating a straw-man argument. Not a single person here is trying to argue that BLDC motors run on "sinusoidal" AC. No one here is saying VFDs produce perfect sinusoidal AC either. We're trying to point out that BLDC motors run on 3-phase AC. They're 3-phase, synchronous AC motors. It doesn't matter that the wave is a square-wave. It's still three phase AC.

You've got it stuck in your head somehow that just because it's not a perfect sine wave, or that because it's "source" is DC, that somehow means it's still DC. That is not true. It switches polarity - it's AC.

You seem to have this line of thought that "AC" can only come from an alternator. Well guess what? Alternators work by applying a DC current to coil to create a magnetic field, and then "modulate" it with a spinning rotor. By your definition, that means a large power plant is just outputting "modulated DC" and therefore ALL power anywhere everywhere is just DC. It's a ridiculous argument.

 

[sberry]

I tend to agree he has a motor with no controller, it was for variable speed.

 

[dogdog]

dam good links for reading.... I was not able to find the 3PH DC gear motor that had that spec on the name plate again... it was probably not an active bid any more in ebay... It is an US made motor.... not no name or other country.

But for OP's case, I think we needed more info, DC motor traditionally have been used for more torque applications, If I remember correctly. So a full pic of that motor would help.


I have a craftsman palm sander and that was DC 115V or what ever volt... it looks like a regular AC sander, plugs into the 120V AC outlet... but if you ever opened it inside, there is a bridge rectifier inside converting the AC into a DC output, Unfiltered, no capacitor.

There is this guy I usually watch for odd ball science stuff I think he had a good collection on motors.

 

[manwithtools]

"It should be understood that the output of this type of inverter is not a pure sine wave. It is a series of d.c. pulses. This can make it unsuitable for certain types of equipment."

 

[Bert_]

20-30 years ago a DC motor and controller was about the only option for speed control, now we have vfd's.

As far as the AC DC argument, If the waveform crosses zero it IS by definition alternating current. Doesn't matter what the waveform looks like.

"It should be understood that the output of this type of inverter is not a pure sine wave. It is a series of d.c. pulses. This can make it unsuitable for certain types of equipment."

In any inverter or VFD those DC pulses will alternate between positive and negative. There's that word again "alternate". What does AC stand for again?

 

[dogdog]

It don't go to negative DC, It's simulated DC pulses (sinusoidal pulse width modulation) . I think you can google SPWM. Don't ask me to explain this, still learning.

As far as OP's original question, It's been mentioned... DC motors are for variable speed before the days of VFDs. Higher voltage higher speed, lower voltage lower speed, and DC motors traditionally have better torque than AC motors.

 

[TractorJeff]

As old as the paint and nameplate are, I go with the 100+ years ago power theory!
As far as the pizzing contest over AC/DC "Alternating Current/Voltage, I find the conversation interesting but looks like a bunch of Fools trying to be the Top Rooster in the Hen House!
Are any of you guys actual Electrical Power Engineers?