Should we talk about power factor?

Please correct me, and add to this.

There are two types of power, real (W) and reactive (VAR), when the amps and volts are in phase, the power factor will be 1 or unity. A resistive load will call for both the W and VAR to be in phase, thus the power factor will be 1. An inductive (motor) load will cause the volts to lag the amps, power factor will be less than 1. A capacative (capacitor) load will cause the volts to lead the amps and power factor will be greater than 1.

The power company must provide both W and VAR to handle the loads. It is most efficient to have the power factor be 1, thus the company does not have to generate and transmit any VAR's. Putting in capacitors that match the inductive (motor) loads will get the two in phase.

Most residential and commercial only get billed for the real power (KW), thus the utility eats the cost of the VAR's. Most industries have to pay for both W and VAR, or VA, so they are incentivized to reduce the VAR demand. This is done by adding capacitors. These capacitor banks are expensive, and have to be controlled by staging them on/off to get power factor as close to 1 as possible.

In the old days all motor loads where inductive, thus power factor was low, so adding capacitors was the answer. Now, a lot of industries are adding VFD's in front of the motors, so their natural power factor is 1, or sometimes greater than 1 which is leading. We are also seeing VFD's on modern air conditioning compressors so power factor on homes should also be closer to 1.

Please comment.

I hope I did not get leading/lagging backwards, it has been about 15 years since I worked with it.

In addition, you cannot start a generator with capacitors attached, as it is a dead short. These capacitor banks must be disconnected during power outages and staged back on when power factor dips as motor loads come back on.

I did get it backwards, inductive load current lags voltage, capacitive load current leads voltage.

Sorry.

You really want to confuse people.

You forgot to mention the problem old men have, impedance.
Which there's a pill for.
George

yeah but can all that keep my beer cold LOL

David, you made one significant error:

"A capacative (capacitor) load will cause the volts to lead the amps and power factor will be greater than 1."

Power factor cannot be greater than one. PF is defined as the cosine of the phase angle between voltage and current. And the cosine of anything must be between -1 and 1. And since current cannot lead or lag voltage by greater than 90 degrees, PF must be between 0 and 1.

The reason utilities want power factor to be unity is that when the power factor is low, they have to deliver more current at a given voltage to get the same power. Generating that extra current doesn't cost them per se, but it results in a lot of resistive losses during transmission. Of course, they can correct the power factor themselves by adding capacitive loads, but that costs money as well.

I've spent the last two years trying to understand power factor. Your explanation is great, but I must have a mental block I cannot figure it out.

We installed 110kw of solar and all the power monitoring equipment to monitor it and our 3PH utility service (1200A 208V). It showed our power factor was low, like .3 or .4, right away. We have few motor loads, the HVAC is most. Rest is lighting and computers. Building with no one in it idles at about 30-40 amps each leg, and is "mostly" balanced. After two years the solar system is only recovering about half the energy cost we expected. The power company blames the power factor. The solar company blames the power company. I've run tests on weekends and at night and even with very little building load, sun shining or not, the PF does not improve. I think it is an instrument or data software problem. This was the first three phase system of this size that the solar company had installed. I never really believed the solar salesman in the first place, but the CEO wanted it so here we are. Odd part is, he installed one on his home (single phase) and it has exceeded expectations. Same brand, same solar company. I'm at wits end with it.

> You forgot to mention the problem old men have, impedance.
> Which there's a pill for. George

George, are you able to achieve unity power factor with help from the Blue Pill?

> We installed 110kw of solar and all the power monitoring equipment to monitor it and our 3PH utility service (1200A 208V). It showed our power factor was low, like .3 or .4, right away.

Are you saying your power factor dropped when you installed the solar power system? Or is it low even if the solar system is disconnected? You kind of need to determine that before you blame the solar system.

I appreciate the comments, yes things are coming back to me.

Power factor does go 0-1 and will be either leading or lagging.

I wasn't very clear. Before the solar project we had no power monitoring at all. So we didn't know what our PF was. As soon as data started being reported it showed poor PF. Even before the solar came online. After it started producing, the PF data didn't change significantly. I'm not blaming the solar system but I'm also not seeing the expected cost recovery either. We were supposed to backfeed and bank kwh to the utility about 80% of our annual usage, but we are rarely banking any and our annual production is only about 40% of our usage.

One theory is the problem is not related to PF at all. Rather we have two problems; the solar estimate was flawed from the beginning and we'll never recover the expected energy. And second the PF data is wrong, some setting in the data collection software is wrong and it is not really as bad as it is reporting.

David;
The slogan I learned in college was ELI the ICE man. In inductive circuits, the Voltage (E) leads the Current (I).

I remembered that after I hit send.

David, VERY INTERESTING to this old power distribution design engineer, thanks for your interest in a deep subject of which non engineers and electricians likely have little interest or knowledge BUT HEY US SPARKIES LOVE IT LOL. Way back when I attended NEC seminars on a regular basis I became interested in the subject, pretty good at it in my day, and put it into actual practice at a huge naval industrial complex where energy charges and penalties (for a poor power factor) were astronomical.

Although its impossible to explain to lay persons in a few sentences what may take up an entire section in an engineering library, I gleaned the net to find a few short n sweet descriptions which may help you and others better understand the subject, here are a few, hope this helps:

FIRST A COUPLE OF MY OWN SHORT DEFINITIONS

FYI

If voltage is applied to a discharged capacitor at Time T = 0+ capacitor initially conducts current and acts as a short circuit so current leads the voltage unlike a resistive unity 1 power factor load where voltage and current are in phase.

If voltage is applied to an Inductor (like a motor) at Time T = 0+ it initially acts like an open circuit so current lags the voltage.

If you balance C with L by adding a capacitor current and voltage can get back in phase for a unity 1 power factor


NOW FOR SOME EXPLANATIONS I FOUND ON THE NET


Power factor is a measure of how effectively you are using electricity. Various types of power are at work to provide us with electrical energy. Here is what each one is doing.

Working Power ? the ?true? or ?real? power used in all electrical appliances to perform the work of heating, lighting, motion, etc. We express this as kW or kilowatts. Common types of resistive loads are electric heating and lighting.
An inductive load, like a motor, compressor or ballast, also requires Reactive Power to generate and sustain a magnetic field in order to operate. We call this non-working power kVAR?s, or kilovolt-amperes-reactive.

Every home and business has both resistive and inductive loads. The ratio between these two types of loads becomes important as you add more inductive equipment. Working power and reactive power make up Apparent Power, which is called kVA, kilovolt-amperes. We determine apparent power using the formula, kVA2 = kV*A.

Going one step further, Power Factor (PF) is the ratio of working power to apparent power, or the formula PF = kW / kVA. A high PF benefits both the customer and utility, while a low PF indicates poor utilization of electrical power.


Here is an example.

A steel stamping operation runs at 100 kW (Working Power) and the Apparent Power meter records 125 kVA. To find the PF, divide 100 kW by 125 kVA to yield a PF of 80%. This means that only 80% of the incoming current does useful work and 20% is wasted through heating up the conductors. Because Laurens Electric must supply both the kW and kVA needs of all customers, the higher the PF is, the more efficient our distribution system becomes.

Improving the PF can maximize current-carrying capacity, improve voltage to equipment, reduce power losses, and lower electric bills. The simplest way to improve power factor is to add PF correction capacitors to the electrical system. PF correction capacitors act as reactive current generators. They help offset the non-working power used by inductive loads, thereby improving the power factor. The interaction between PF capacitors and specialized equipment, such as variable speed drives, requires a well designed system.

PF correction capacitors can switch on every day when the inductive equipment starts. Switching a capacitor on can produce a very brief ?over-voltage? condition. If a customer has problems with variable speed drives turning themselves off due to ?over-voltage? at roughly the same time every day, investigate the switching control sequence. If a customer complains about fuses blowing on some but not all, of their capacitors, check for harmonic currents.

HERE ARE A COUPLE VERY SHORT DEFINITIONS

The ratio of the actual electrical power dissipated by an AC circuit to the product of the r.m.s. values of current and voltage. The difference between the two is caused by reactance in the circuit and represents power that does no useful work.

In electrical engineering, the power factor of an AC electrical power system is defined as the ratio of the real power absorbed by the load to the apparent power flowing in the circuit, and is a dimensionless number in the closed interval of −1 to 1.

SORRY if this bores others and THANKS DAVID for opening an interesting and informative thread, hope the above helps but no warranty lol

God Bless and protect the USA in these difficult times, keep her safe strong and great

John T Longggggggggg retired n rusty power distribution design engineer but still love this sparky chat

John,

Saying power factor is the efficiency factor is a good analogy, a motor cant produce work if there are no amps.

AMEN David, one way it was described in a NEC Seminar I attended was in a motor in addition to the real "work" (spinning the shaft) a motor produced it took other additional energy to create the motors magnetic field ALL OF WHICH IS INDUCTIVE. The utility took PF and VAR's into account and had to produce that additional energy so charged us for it. Makes sense to me lol

FUN THREAD for us sparkies. Hey you started it, all your fault lol

Take care and be safe David, pleasure chatting with you

John T Once an engineer always an engineer lol

Its getting late but wanted to add some info regarding solar.

A Solar panel produces DC NOT AC. Typically its used to charge a DC battery bank and that DC energy can be electronically Inverted into 120 Volt 60 HZ AC. I have a Pure Sine wave Inverter which electronically produces clean 60 cycle AC power. Nowwwwwww if your utility allows Grid Tie of your solar system to theirs the quality of what you provide is subject to the Inverters quality and of course, the two must be in sync. Im unsure how all that affects Power Factor, I remember it being discussed below but its getting late I will look again tomorrow

Good night yall

John T

Probably showing my ignorance here, think I kinda sorta maybe understand a little of this...

So what does the PF rating on an electric motor mean?

Is it an efficiency factor?

Why would there be different ratings?

A big place we work in uses about 5 MW when everything is up and running. I know they have a lot of transformers but I don't recall seeing a capacitor bank anywhere. The feed into the building, IIRC, is 12.5 KV.

> So what does the PF rating on an electric motor mean?

It means that's the power factor that particular motor will present when it's running at rated load. In other words, if you measured the phase angle between the voltage applied to the motor and the current it draws, that phase angle would be the arccosine of its rated power factor.

More practically speaking, the power factor tells you the ratio between the POWER consumed by the motor and the VOLT-AMPS consumed by the motor. I'll follow up with an example in a bit.

Just a bit of background: "Phase angle" refers to the delay between the voltage and current waveforms in an AC circuit. You're probably aware that in an AC circuit, the voltage and current reverse directions 120 times per second. But you may not realize that they don't switch directions at the same time. That difference, expressed in degrees, is the phase angle. It is "leading" (current reverses before voltage) in a capacitive circuit and "lagging" (current reverses after voltage) in an inductive circuit.

> Is it an efficiency factor?

No. All electric motors are nearly 100 percent efficient regardless of power factor. But it does affect how efficiently power can be delivered to the motor, which is why anyone cares.

> Why would there be different ratings?

It's not so much a rating as it is a property of the motor. Inductive motors have fairly low power factors, while synchronous motors have higher PFs. Adding a run capacitor improves a motor's PF.

OK, so here's a practical example:

You have a 120V motor rated at 1/2 horsepower with a power factor of 0.7.
- 0.5 hp x 746 watts/hp = 373 watts
- 373 watts ÷ 0.7 volt-amps/watt = 583 volt-amps
- 583 volt-amps ÷ 120 volts = 4.4 amps
So the motor will draw 4.4 amps at rated load.

John, I have to take issue with a couple of things in the information you pulled from the (almost always infallible) web:

"A steel stamping operation runs at 100 kW (Working Power) and the Apparent Power meter records 125 kVA. To find the PF, divide 100 kW by 125 kVA to yield a PF of 80%. This means that only 80% of the incoming current does useful work and 20% is wasted through heating up the conductors."

That's obviously not true. The 20 percent isn't "wasted"; rather it doesn't do anything. It is due to stored energy that gets passed back and forth between the utility and the inductive loads of the customer. Yes, there is some loss due to resistance in the conductors in power distribution network, but that's nowhere near the full 20 percent.

"In electrical engineering, the power factor of an AC electrical power system is defined as the ratio of the real power absorbed by the load to the apparent power flowing in the circuit, and is a dimensionless number in the closed interval of −1 to 1."

Mathematically speaking, yes. But in the real world the phase angle between voltage and current never exceeds 90 degrees, so there is no such thing as a negative power factor.

> As soon as data started being reported it showed poor PF. Even before the solar came online. After it started producing, the PF data didn't change significantly.

OK, so as part of the instrumentation for your solar installation, power factor is now monitored at the meter and is ~0.20 without having the solar on-line.

That is surprisingly low, and I would suspect a problem in the instrumentation. Perhaps you can take different loads off line and see if there's something in particular that is pulling down the PF. Unfortunately, there's no easy way to validate the power factor measurement.

The line breaks in my example got removed in Classic View. It looks fine in Modern View.

Here it is again with the line breaks (hopefully) put back in:

You have a 120V motor rated at 1/2 horsepower with a power factor of 0.7.

- 0.5 hp x 746 watts/hp = 373 watts

- 373 watts ? 0.7 volt-amps/watt = 583 volt-amps

- 583 volt-amps ? 120 volts = 4.4 amps

So the motor will draw 4.4 amps at rated load.

As I have not actually taken the time to learn this before:

A motor will have two capacitors on it, I understand one is the start and one the run (typically).

So, the start capacitor would be normally discharged, such that when the motor initially is energized, the capacitor would act as a short circuit to counteract the motor acting as an open circuit, to balance the two?

The run capacitor is charged, then discharges to make up for the losses from creating the magnetic field in the motor, that is, to encourage the power factor back towards unity?

The analogy that training uses at our power plant is that of buying a draft beer- you get the foam with the beer, some more than others, whether you want it or not. Reactive power is the foam, real power is the liquid, apparent power is everything in the glass.

Like many things, operating a power plant is far different than designing one- I cannot change the reactive power of our customers' loads, only know the limits I can supply. I cannot change the thermal efficiency of a heat exchanger, and sometimes I cannot change the conditions of the inputs- temperature of the Lake, for example. I need to know what I can change, like flow rate of the Lake water, and how that affects my results.

> A motor will have two capacitors on it, I understand one is the start and one the run (typically).
So, the start capacitor would be normally discharged, such that when the motor initially is energized, the capacitor would act as a short circuit to counteract the motor acting as an open circuit, to balance the two?

We really don't talk about capacitors charging and discharging in AC circuits. Charging and discharging is something that happens in the time domain, and we usually describe AC circuits in the frequency domain. So we talk about "phase angle", which is the delay between the voltage and current waveforms in an AC circuit.

The starting capacitor is used to create a phase shift in the motor windings, which generates torque to start the motor. AC motors need something to initially get them spinning; once they are spinning they have a rotating field. But until they spin, the start capacitor creates the rotating field.

The run capacitor, if there is one, serves two purposes: It generates a phase shift for additional torque while running. And it also adds some power factor correction to the motor, thereby reducing current draw.

Mark about the ONLY things I will stand behind are the short bits of information I posted myself. If you take issue with any of the other sources (off the net may be right or wrong???) Id try to get in touch with them. I copied and pasted them and did NOT analyze them and for sure THEY MAY BE WRONG If I have time I will thoroughly study them to see if I agree with you or the authors. Ive been long retired as a power distribution design engineer but will study the authors versus what you posted

THANKS FOR taking the time to review and comment on what I found on the net (they were NOT my thoughts)

Best wishes, God Bless you and your family, keep safe

God Bless America keep her safe strong and great

John T

Thanks, Mark. That makes more sense, since I wasn't sure how the start would be discharged prior to starting. I'm sure I have heard this before, just not provided a fertile ground for the idea to germinate.

K, GREAT question and you are really into this, I appreciate that. I wish you had asked me that question when I was an Engineer at The Century Electric Motor Company, I worked with and understood it much better then grrrrrrrrrrr. That being said here is my best recollection which may help yourself and others, lay persons as well as other engineers and electricians.

Unlike a three phase motor a single phase is NOT self starting. A single phase split phase motor uses an offset start winding (engaged until a centrifugal switch opens it at X RPM) to get the motor started turning in one particular direction. That start winding may or may NOT also have a (start) capacitor but if it does the starting torque is increased. In addition to improve efficiency a single phase motor may ALSO have a run capacitor in the run winding.

NOTE a single phase split phase motor can work with or without a Start orrrrrrr a Run capacitor. It may have ONLY a start capacitor and it may or may not also have a Run capacitor.

FYI at Time T = 0+ a capacitor starts to conduct current acting like a near short circuit UNTIL its charged at which time to DC it becomes like an OPEN circuit IE its fully charged. In an AC circuit where current flow alternates Impedance (sort of like AC resistance, frequency dependent) comes into play and a capacitor cycles. In a capacitor current leads the voltage.

CONVERSELY at Time T = 0+ an Inductor (like a motor winding) resists initial current flow in which case current lags the voltage

In a pure resistive circuit current and voltage are in phase so if power factor correction is used in say a motor the capacitance and inductance balance out KW = KVA unity one power factor

NOTE Its IMPOSSIBLE to explain here what may takes longggggggggggg study education and experience to explain and understand and this IS NOT PERFECT OR EXACT its ONLY a very basic attempt to educate lay people as well as electricians BUT I TRY MY BEST TO HELP

Go study up electrical engineering to get a better handle on all this, I cant explain years of study and experience here in a paragraph sorryyyyyyyy lol

Best wishes, God Bless America in this time, keep her safe strong and great

John T Too longggggggggg retired n rusty EE

One thing (maybe) not mentioned, is the effect of low power factor on other electrical, and electronic equipment in use at the same location, and/or on that same branch all the way back to the system of generation. One reason the utility wants to "see" a unity PF is to avoid the phase error in its delivery. In the past (maybe 60 years ago) selling extra electricity to make motors work at rated HP was valued as a source of revenue much more than it is today, and less consequential. Jim

Steve, you and I have chatted numerous times concerning electricity and I think you understand more then you give yourself credit for. Even for many electricians and even engineers who are more into electronics then electricity this can be a challenging subject. I'm short on time today and as yall know Im long retired as an EE but will try to give you brief answers while NOT perfect or exact (no way I can cover in a sentence here what it may take volumes to fully and correctly explain).

You ask:

1) So what does the PF rating on an electric motor mean?


The formula is PF = kW / KVA. If Capacitance and Inductance were perfectly balanced like a resistive circuit with a unity one power factor, then KW would = KVA

Another formulation is PF = True Power (KW) / Apparent Power (KVA)

Given an ideal circuit with a sinusoidal input PF is cos ?, where ? is the phase angle between the voltage and current. Im sure you already understand in a capacitor current leads the voltage while in an inductor it lags, but if the two are balanced its like a resistive circuit with a unity power factor.


2) Is it an efficiency factor?

NO Due to I Squared R inefficiency heat losses, a motor like other electrical appliances is NOT 100% efficient. The laws of conservation of energy teach us energy in = energy out HOWEVER some of what comes out is heat NOT energy to turn the motor and power a load.

3) Why would there be different ratings?

One concerns KW versus KVA, the difference, and the resultant Power Factor while the other is energy in versus out.

There ya go Steve, again this is nowhere near exact or perfect or 100% engineering correct, just very general to help you out.

Hope this helps, best wishes to you keep safe now

God Bless America

John T Gettin too old for all this hard brain cell work lOl no warranty consult more current trained professional electricians and engineers not meeeeeeeeeeeeeeeeee.

(quoted from post at 07:00:48 03/29/20) The line breaks in my example got removed in Classic View. It looks fine in Modern View.

Here it is again with the line breaks (hopefully) put back in:

You have a 120V motor rated at 1/2 horsepower with a power factor of 0.7.

- 0.5 hp x 746 watts/hp = 373 watts

- 373 watts ? 0.7 volt-amps/watt = 583 volt-amps

- 583 volt-amps ? 120 volts = 4.4 amps

So the motor will draw 4.4 amps at rated load.

Click to expand...

Place a 1/4HP load on that 1/2HP motor and the power factor will lag to lower number .

Thanks for the help. It is certainly a complicated problem. I'm sure it has a solution but so far it has eluded everyone who has looked at it.

(quoted from post at 16:50:00 03/29/20) Thanks for the help. It is certainly a complicated problem. I'm sure it has a solution but so far it has eluded everyone who has looked at it.

Click to expand...

he question was , "should we talk about power factor?" Unless you are a large commercial user, the answer should elude no one and is a simple NO! Why should you spend a moment of time or money to unburden the power company? It sure does not 'elude' me & if for a moment it did, I have a shelf full of my engineering text boos to refresh my memory. I suppose the whole post was to engage some in conversation....to each his own.

Hey my old sparky friend, I hear you, but how many times have you observed same as myself that anytime an electrical or legal question is asked everyone (including tours truly) lay or professional, electricians or engineers, comes out of the woodwork and pretty much EVERYONE has an "answer". IT JUST GOES WITH THE TERRITORY ON HERE and I've been around and seen it come true like 30 years. Usually a carpentry or plumbing or farming or even tractor question doesn't draw so many opinions AND THIS IS SUPPOSED TO BE AN OLD TRACTOR FORUM ?????????

Just a fine group of gents all trying to help, and I do likewise.

Take care keep safe and best wishes, nice chatting with you

God Bless America and all here

John T

> Unless you are a large commercial user, the answer should elude no one and is a simple NO!

Who peed in your Cheerios? This was at worst a harmless discussion, and at best folks learned a few things.

Actually, power factor is very relevant for anyone who wants to size the electric service for a heavy inductive load such as an air compressor or welder. How you gonna size the wiring for a big motor if you don't know how to calculate volt-amps based on the motor's horsepower and power factor ratings?

Unlike a three phase motor a single phase is NOT self starting. A single phase split phase motor uses an offset start winding (engaged until a centrifugal switch opens it at X RPM) to get the motor started turning in one particular direction. That start winding may or may NOT also have a (start) capacitor but if it does the starting torque is increased. In addition to improve efficiency a single phase motor may ALSO have a run capacitor in the run winding.

NOTE a single phase split phase motor can work with or without a Start orrrrrrr a Run capacitor. It may have ONLY a start capacitor and it may or may not also have a Run capacitor.

Click to expand...

Thanks, John. I learned some from a previous employer who had been trained in electric motor rewinding/repair. I didn't want to muddy the water with three phase motor talk in relation to starting, I am aware they act differently.

I also have been exposed to the older motors with centrifugal start switches and separate start windings-those made sense and were visually obvious to me. When it came to using a capacitor, I just said it was a magic silver box that replaced the extra windings and switch, and left it at that. Knowing how to spot a blown capacitor and get a proper replacement was more important than understanding exactly how they worked.

I know the feeling you have for lost proficiency- I was once a Professor's assistant for a Statistics class for several semesters. Now, I can barely spell Statistics!

Keep the electrons flowing, stay safe and healthy!

(quoted from post at 20:34:18 03/29/20) > Unless you are a large commercial user, the answer should elude no one and is a simple NO!

Who peed in your Cheerios? This was at worst a harmless discussion, and at best folks learned a few things.

Actually, power factor is very relevant for anyone who wants to size the electric service for a heavy inductive load such as an air compressor or welder. How you gonna size the wiring for a big motor if you don't know how to calculate volt-amps based on the motor's horsepower and power factor ratings?

Click to expand...

reat! You can parrot the 'dog''. Congrats on your great achievement! You win a cupie doll!

You're welcome K, great sparky chatting with you. Perhaps a lay persons bottom line regarding the addition of a capacitor in the start winding to know is it can increase starting torque versus a straight split phase motor. Them darn single phase motors not being self starting need a little "push/start" and guidance as to which direction to start spinning lol

My uncle had a bench grinder and wire wheel with a faulty start winding or switch so he turned on the power and using a glove gave it a healthy spin in the direction he wanted it to turn AND AT AGE 12 (when I first became an electrical hobbyist) I WAS AMAZED LOL

FYI Some low torque motors like a small fan perhaps still have their required start winding to get them going in a certain direction HOWEVER there's no centrifugal switch to dis engage the separate start winding at X RPM it remains in the circuit. Those were called "shaded pole"

Even though its been yearssssss since I was an engineer at the Century Electric Motor Company I STILL ENJOY THS CHAT

Take care, its a pleasure sparky chatting with you and others

John T

I remember the electric alarm clock in my folks bedroom. If the power had been off, you needed to turn a little wheel on the back of it to start it. And be sure that you turned it in the right direction.

Dusty

ELI the ICE man.... Bet you will never forget again....

Thanks MarkB, JohnT and the others who have added to this thread. I've thoroughly enjoyed this topic, and have a better understanding of PF, and the relation between KVA and KW.
Back in the day, we had an instructor that tried to explain PF. He knew his stuff, but had difficulty passing it on to us, and those classes just ended in all around frustration. I'll bet there are still classmates that cringe at the mention of leading or lagging.
I got a short empirical course years later when working in an industrial plant that had suffered a fire- we replaced a number of well aged motors with VFDs, and gained an improvement in PF.

I always like to learn neat stuff.
Hunker down and stay safe, unc

And thanks to David for starting all this !!!!!!!!!!!!

John T