Electrical help please

A friend of mine here on Whidbey Island has a welding business. It's
pretty new, only a few years now. Anyway, he called me yesterday with
an electrical problem. Puget Sound Energy (PSE) has had complaints
from neighbors about voltage spikes or drops, my friend wasn't clear
on this, but they showed him a graph which I have yet to see. The
solution PSE is proposing is a new xmfr at the pole. PSE told my
friend the problem is because of the hard starting welder. The welder
is an older xmfr type machine with lots of copper. At full load it is
rated at 11 kw, which is about 46 amps. But I don't know what the
current spkies to when he first steps on the pedal. The machine is now
wired for single phase but can be wired for three phase. What he wants
to know is if he ran the welder from a Rotary Phase Converter would
the current spikes and voltage drops be less. I don't know. I also
don't know if there is a way besides my friend paying thousands for
PSE to install a new xmfr on the pole for this situation to be
ameliorated. He can't afford at this time for a new welder with a
softer start setting. Besides, the hard fast start means his employee
can make more welds. Any help would be greatly appreciated.
Thanks,
Eric

 

I scrapped a reply here bcause there werre too many unkowns. Options with the power company for one, they could run a dedicated line putting him up the food chain a bit. Probably not free.

I think you're right about the generator idea, that is unless the power company will do it for free. (they will if you are Ford, they did it in Ohio)

But this all made me run the numbers. I found this page :

http://www.dieselserviceandsupply.com/Diesel_Fuel_Consumption.aspx

The 20KW job at ž load uses 1.3 gallons/hour. That works out to about 0.33/kWh. The national average of electric rates is 0.13/kWh. With diesel at $4.00/gallon, a 2080 hour work year, 50 % duty cycle, about four grand a year ? Well the power company, with average rates would have been over a third of that anyway, plus the fact that welders make money. Th employer shojld be doubling his money on what the guy makes. So if the guy makes $25 an hour, the company should be getting $75 an hour. Times 2080 work hours, that four grand doesn't look so big. Plus there are certain advantages, like he can work in a pwoer outage. If he is making a profit it is a good thing to keep working. So really, it might be a good idea. It may be one of those times when penny pinching does not pay.

The thing is though is that the power company sells power. They WANT to sell power. I think they should refeed the guy and give him the aperage he needs. However the fact that they came and had a talk with him indicates that thy mght not want to do anyting, especially for free. If noting else they might hit him with a peak load meter, which means $0.13/kWWh is probably out the window.

We still need a little bit more info, like what did the power company actually SAY. In that area, CAN they asses you for too much load ? Or cut you off ? That is the main question. If not, they will just have to eat it, so basically I wuld buy nothing until I hear about them.

(but thanks for sending me on that hunt, because I thought running generators was ALOT less efficient than that)

 

[Maynard A. Philbrook Jr.]

In article <k7s45ad2fek6ljc1rcqto28nhchv8i0crr@4ax.com>,
etpm@whidbey.com says...

A friend of mine here on Whidbey Island has a welding business. It's
pretty new, only a few years now. Anyway, he called me yesterday with
an electrical problem. Puget Sound Energy (PSE) has had complaints
from neighbors about voltage spikes or drops, my friend wasn't clear
on this, but they showed him a graph which I have yet to see. The
solution PSE is proposing is a new xmfr at the pole. PSE told my
friend the problem is because of the hard starting welder. The welder
is an older xmfr type machine with lots of copper. At full load it is
rated at 11 kw, which is about 46 amps. But I don't know what the
current spkies to when he first steps on the pedal. The machine is now
wired for single phase but can be wired for three phase. What he wants
to know is if he ran the welder from a Rotary Phase Converter would
the current spikes and voltage drops be less. I don't know. I also
don't know if there is a way besides my friend paying thousands for
PSE to install a new xmfr on the pole for this situation to be
ameliorated. He can't afford at this time for a new welder with a
softer start setting. Besides, the hard fast start means his employee
can make more welds. Any help would be greatly appreciated.
Thanks,
Eric

it maybe better for him to get self powered welder (Generator combo) or
get a 20kVA generator that is diesel operated. Also puts out 3 phase at
230 volts to make it more efficient..

Last time I looked you can get a diesel gen of that type from Harbor
freight somewhere around 5k. It's well worth to have in cases that he's
running into.

It's more than likely the electric company has too many people on the
same transformer, he would benefit greatly if he had his own
transformer. The cost shouldn't be that much different, on a business
point of view.

That situation sounds like they don't have a lot of generating capacity
on the island.

Jamie

 

On Thu, 30 Oct 2014 16:12:38 -0700 (PDT), jurb6006@gmail.com wrote:

I scrapped a reply here bcause there werre too many unkowns. Options with the power company for one, they could run a dedicated line putting him up the food chain a bit. Probably not free.

I think you're right about the generator idea, that is unless the power company will do it for free. (they will if you are Ford, they did it in Ohio)

But this all made me run the numbers. I found this page :

http://www.dieselserviceandsupply.com/Diesel_Fuel_Consumption.aspx

The 20KW job at ž load uses 1.3 gallons/hour. That works out to about 0.33/kWh. The national average of electric rates is 0.13/kWh. With diesel at $4.00/gallon, a 2080 hour work year, 50 % duty cycle, about four grand a year ? Well the power company, with average rates would have been over a third of that anyway, plus the fact that welders make money. Th employer shojld be doubling his money on what the guy makes. So if the guy makes $25 an hour, the company should be getting $75 an hour. Times 2080 work hours, that four grand doesn't look so big. Plus there are certain advantages, like he can work in a pwoer outage. If he is making a profit it is a good thing to keep working. So really, it might be a good idea. It may be one of those times when penny pinching does not pay.

The thing is though is that the power company sells power. They WANT to sell power. I think they should refeed the guy and give him the aperage he needs. However the fact that they came and had a talk with him indicates that thy mght not want to do anyting, especially for free. If noting else they might hit him with a peak load meter, which means $0.13/kWWh is probably out the window.

We still need a little bit more info, like what did the power company actually SAY. In that area, CAN they asses you for too much load ? Or cut you off ? That is the main question. If not, they will just have to eat it, so basically I wuld buy nothing until I hear about them.

(but thanks for sending me on that hunt, because I thought running generators was ALOT less efficient than that)

His power bill for the business is about $200.00 per month. For the
kind of money the generator would cost he could buy a new inverter
welder that would not have the same high current draw when starting.
But right now he can't afford a new inverter welder. I'm not sure if
he can force the power company pay for a new xmfr. I'm also not sure
that the power company can install a new xmfr and then force him to
pay. I do know that in my case, where the voltage is way high,
sometimes as high as 260 volts, I was not able to force the power
company to lower the voltage and instead I had to install at my cost
buck xmfrs so I could run one particular CNC lathe. What about wiring
in power factor correcting caps?
Eric

 

Problem with the new transforer idea is it might not work. They might concievably have to put in miles of lines to get him to the higher voltage lines.. this would spread his load out to more of the whole tree. More people would get a voltage drop, but thet drop would not be as severe.

He needs to have a powow with the power company I guess, or maybe not do anything for now. From what I read you said they approached him ? Need to know ore about that. They must have said something. They don't just drop by for coffee.

Checking local laws may or may not do any good. There may be none. It may be that if you want to deal with the power company, you do it on their terms.. Some power companies are owned by the municipality, county, who knows. Others are totally private.

One main thing to remember is they want that $200 a month. It is not alot of money but it is more than many pay. Therefore he should always keep the fact that he CAN buy a diesel generator in his pocket if they try to bully him for a bunch of money. Another question is - just how much of a PITA would it be to move the business ? (I don't mean cross contry here, I mean a few miles closer to the power station)

 

On Fri, 31 Oct 2014 08:54:51 -0700 (PDT), jurb6006@gmail.com wrote:

Problem with the new transforer idea is it might not work. They might concievably have to put in miles of lines to get him to the higher voltage lines. this would spread his load out to more of the whole tree. More people would get a voltage drop, but thet drop would not be as severe.

He needs to have a powow with the power company I guess, or maybe not do anything for now. From what I read you said they approached him ? Need to know ore about that. They must have said something. They don't just drop by for coffee.

Checking local laws may or may not do any good. There may be none. It may be that if you want to deal with the power company, you do it on their terms. Some power companies are owned by the municipality, county, who knows. Others are totally private.

One main thing to remember is they want that $200 a month. It is not alot of money but it is more than many pay. Therefore he should always keep the fact that he CAN buy a diesel generator in his pocket if they try to bully him for a bunch of money. Another question is - just how much of a PITA would it be to move the business ? (I don't mean cross contry here, I mean a few miles closer to the power station)

He would move the business if there were a place for it fairly close.
We spoke about that last night. There are the main power lines running
down the island within 1/4 mile and the xmfr is mounted on a pole
acroos the narrow street from his driveway. He would like 3 ohase but
the power company wants loads of dough for that option too.
Eric

 

[Jasen Betts]

On 2014-10-30, etpm@whidbey.com <etpm@whidbey.com> wrote:

A friend of mine here on Whidbey Island has a welding business. It's
pretty new, only a few years now. Anyway, he called me yesterday with
an electrical problem. Puget Sound Energy (PSE) has had complaints
from neighbors about voltage spikes or drops, my friend wasn't clear
on this, but they showed him a graph which I have yet to see. The
solution PSE is proposing is a new xmfr at the pole. PSE told my
friend the problem is because of the hard starting welder. The welder
is an older xmfr type machine with lots of copper. At full load it is
rated at 11 kw, which is about 46 amps. But I don't know what the
current spkies to when he first steps on the pedal. The machine is now
wired for single phase but can be wired for three phase. What he wants
to know is if he ran the welder from a Rotary Phase Converter would
the current spikes and voltage drops be less.

yes, that would reduce them. rotary converters store energy in
rotational momentum, and some of that energy will go into serving the
start-up.

--
umop apisdn

 

etpm@whidbey.com wrote:
> A friend of mine here on Whidbey Island has a welding business.

Today I learned that there is a piece of water called "Useless Bay".

The machine is now wired for single phase but can be wired for three
phase. What he wants to know is if he ran the welder from a Rotary
Phase Converter would the current spikes and voltage drops be less.

Maybe. It might help the startup, but the rotary converter isn't 100%
efficient, so it would add a little energy use on top of what the
welder needs.

The rotary converters I know about have to be switched on manually when
you want them. This means that if you start welding, and then stop to
move the ground clamp or get a new rod or whatever, the rotary
converter is still running. It won't draw much power when running with
no load, but again, it's more than just the welder itself with no
converter. Maybe you can get a rotary converter that can switch itself
on and off based on load.

One phase converter vendor I Googled up says that for a welder, you can
size the converter as if it was a resistive load. That means an
(11,000/746) or 14.7 hp converter. They sell a 15 hp model for $2,360
and a 20 hp for $2,775. Add the freight costs for 200-250 pounds of
machine, and sales tax, and IMHO you've made a pretty good dent in the
price of a new welder. Cheaper phase converters probably exist.

I also don't know if there is a way besides my friend paying thousands
for PSE to install a new xmfr on the pole for this situation to be
ameliorated.

They should be able to adjust the taps on the big transformer (not the
one on the pole - the big one that feeds that one) to increase the
voltage a little, but that also means the voltage will be higher when
he isn't welding. It also might mean that the voltage is too high all
the time for the people that live near the big transformer. They may
decline to do it for these reasons, but it's possible.

The tarriffs for electricity should be somewhere either on the power
company or state government web site. The bill should say which rate
plan or tarriff applies. Usually these are mostly about the price,
but there may be something in there about who has to fix power quality
problems. Your state Public Utilities Commission (or similar name)
may also be able to advice. (This may be different if Washington has
deregulated electric power. In that case, an accountant two time zones
away makes up whatever rules will generate the most revenue, and changes
the rules hourly.)

Looking through a Northern Tool catalog I have, portable gasoline motor-
generators rated at 13.5 to 15.0 kW continous seem to go for $3,000 to
$4,000 depending on make. There are some cheaper ones if you don't
need to support 11 kW all the time.

If your friend already owns an engine, he can buy just the generator
head and rig it up himself. You can get ones that run at 3,600 rpm
plus or minus, or ones that are designed to run from 540 rpm from a
tractor PTO shaft. Bonus: you can unhitch the motor from the tractor
and drive the tractor to the fuel, rather than hauling the fuel to a
motor-generator. That same catalog has a 12 kW PTO generator, which
says it needs at least a a 24 hp engine, for $1,500.

If nothing else changes, bad connections would tend to make the welder
draw *less* power. But maybe the user is cranking up the welder output
power to make up for lower voltage. It might not hurt to at least
eyeball how the welder is hooked up to the 240 V AC - is the wire thick
enough, are all the connections tight, etc? The fancy way to figure
this out is to run the welder for a while and then look at the breaker
box / wiring with an infrared camera (like a FLIR). The middle way is
to use an infrared thermometer. The cheap way is to (really carefully!)
touch the wires to see if they are hot - don't get shocked.

Standard disclaimers apply: I don't get money or other consideration
from any companies mentioned.

Matt Roberds

 

[whit3rd]

On Friday, October 31, 2014 3:01:27 PM UTC-7, Jasen Betts wrote:

On 2014-10-30, etpm@whidbey.com <etpm@whidbey.com> wrote:
A friend of mine here on Whidbey Island has a welding business. It's
pretty new, only a few years now. Anyway, he called me yesterday with
an electrical problem. Puget Sound Energy (PSE) has had complaints
from neighbors about voltage spikes or drops... What he wants
to know is if he ran the welder from a Rotary Phase Converter would
the current spikes and voltage drops be less.

yes, that would reduce them. rotary converters store energy in
rotational momentum, and some of that energy will go into serving the
start-up.

The rotary converter would help, but so would a simple idling AC motor
plugged in next to the welder. It's the flywheel effect that pulls energy
from electrical spikes and dumps energy into dips. You could even
mount some heavy rotors (with suitable balancing) to the motor shaft.

 

On Sat, 1 Nov 2014 03:26:11 +0000 (UTC), mroberds@att.net wrote:

etpm@whidbey.com wrote:
A friend of mine here on Whidbey Island has a welding business.

Today I learned that there is a piece of water called "Useless Bay".

The machine is now wired for single phase but can be wired for three
phase. What he wants to know is if he ran the welder from a Rotary
Phase Converter would the current spikes and voltage drops be less.

Maybe. It might help the startup, but the rotary converter isn't 100%
efficient, so it would add a little energy use on top of what the
welder needs.

The rotary converters I know about have to be switched on manually when
you want them. This means that if you start welding, and then stop to
move the ground clamp or get a new rod or whatever, the rotary
converter is still running. It won't draw much power when running with
no load, but again, it's more than just the welder itself with no
converter. Maybe you can get a rotary converter that can switch itself
on and off based on load.

One phase converter vendor I Googled up says that for a welder, you can
size the converter as if it was a resistive load. That means an
(11,000/746) or 14.7 hp converter. They sell a 15 hp model for $2,360
and a 20 hp for $2,775. Add the freight costs for 200-250 pounds of
machine, and sales tax, and IMHO you've made a pretty good dent in the
price of a new welder. Cheaper phase converters probably exist.

I also don't know if there is a way besides my friend paying thousands
for PSE to install a new xmfr on the pole for this situation to be
ameliorated.

They should be able to adjust the taps on the big transformer (not the
one on the pole - the big one that feeds that one) to increase the
voltage a little, but that also means the voltage will be higher when
he isn't welding. It also might mean that the voltage is too high all
the time for the people that live near the big transformer. They may
decline to do it for these reasons, but it's possible.

The tarriffs for electricity should be somewhere either on the power
company or state government web site. The bill should say which rate
plan or tarriff applies. Usually these are mostly about the price,
but there may be something in there about who has to fix power quality
problems. Your state Public Utilities Commission (or similar name)
may also be able to advice. (This may be different if Washington has
deregulated electric power. In that case, an accountant two time zones
away makes up whatever rules will generate the most revenue, and changes
the rules hourly.)

Looking through a Northern Tool catalog I have, portable gasoline motor-
generators rated at 13.5 to 15.0 kW continous seem to go for $3,000 to
$4,000 depending on make. There are some cheaper ones if you don't
need to support 11 kW all the time.

If your friend already owns an engine, he can buy just the generator
head and rig it up himself. You can get ones that run at 3,600 rpm
plus or minus, or ones that are designed to run from 540 rpm from a
tractor PTO shaft. Bonus: you can unhitch the motor from the tractor
and drive the tractor to the fuel, rather than hauling the fuel to a
motor-generator. That same catalog has a 12 kW PTO generator, which
says it needs at least a a 24 hp engine, for $1,500.

If nothing else changes, bad connections would tend to make the welder
draw *less* power. But maybe the user is cranking up the welder output
power to make up for lower voltage. It might not hurt to at least
eyeball how the welder is hooked up to the 240 V AC - is the wire thick
enough, are all the connections tight, etc? The fancy way to figure
this out is to run the welder for a while and then look at the breaker
box / wiring with an infrared camera (like a FLIR). The middle way is
to use an infrared thermometer. The cheap way is to (really carefully!)
touch the wires to see if they are hot - don't get shocked.

Standard disclaimers apply: I don't get money or other consideration
from any companies mentioned.

Matt Roberds

I can build him a phase converter. At least I understand how they
work, even though I don't understand a lot about AC. I have built a
few rotary phase converters and they all work properly. I was
wondering just how much energy would be stored in the motor and if it
would have a significant effect on the current surge. I also know
about the high voltage thing. Since I am near the beginning of a long
run the voltage at my shop is often 260 volts. Most of my machines can
handle this higher voltage but the spindle drive in one machine
couldn't handle it so I had to put in buck xmfrs.
Eric

 

etpm@whidbey.com wrote:

I was wondering just how much energy would be stored in the motor and
if it would have a significant effect on the current surge.

I guess you could get an estimate by thinking about running a motor open
shaft, and assuming that all of the starting current goes into getting
the rotor up to speed. [1]

Just as a WAG, assume you have a 1 hp 240 V motor, rated at 6 A full
load. Say it takes 1 second to come up to speed and takes 3x the normal
full load current to start (even when it's starting open shaft). Then
you have 18 A * 240 V * 1 s = 4320 watt-sec of energy stored in the
rotor. [2]

If you wanted to take energy back out for 0.5 seconds, and you didn't
care if that completely stalled the motor down to zero RPM, you could
get a maximum of 8620 watts back out of it in that time period. Or, if
you wanted to take energy back out for 2 seconds, and going to 0 RPM is
OK, you could get maximum 2160 watts back out of it. In reality you
will get less, but this should put an upper bound on it.

Adjust as needed for the size of motor you are thinking about, how
much startup current you think it draws and for how long, and over what
period of time you think you will need it. Probably the shortest period
of time to consider is 0.0167 sec, one 60 Hz cycle.

Matt Roberds

[1] In reality, some of it goes to heating up the windings and the
bearings, pushing air around, etc.

[2] OK, VA-sec, power factor, and all that. I'm just trying to make an
estimate here.