Messages

1501

Pumps, Wells, Tanks, Controls / VFD Power Consumption

« on: August 11, 2008, 09:00:40 AM »

Many VFD articles are typically full of hype or misinformation.  There is no way to make a 100 HP motor pull only 12.5 HP load, and still maintain the head or pressure required. Authors show the formula for the Affinity Law. However, like all VFD salespeople, they fail to use any part of it except the part that reduces the HP by the cube of the speed. The most important part of the Affinity Law is that the head is reduced by the square of the speed. This means that the pump can only be slowed by 10% to 15% at the most, or it is no longer getting water to the surface of the well, or it is no longer producing enough pressure to operate the sprinklers.

Here are a couple of accurate curves that show the relationship between VFD and throttling. Note the line for TDH required, and the minimum speed possible to produce this head. Then you can see that in reality, there is very little if any difference in power consumed by the VFD system and a throttling valve system.

Thanks

Cary

1502

Pumps, Wells, Tanks, Controls / VFD Power Consumption

« on: August 11, 2008, 08:57:30 AM »

xxxxxxxxxxxxxxxxxx

1503

Pumps, Wells, Tanks, Controls / Oregon Nursery loves CSV

« on: August 08, 2008, 11:25:25 AM »

A large nursery in Oregon uses several Cycle Stop Valve to control irrigation pumps.  They have been using CSV's for several years and find that they give excellent control and dependable service.  Recently a salesman talked them into trying a different brand of valve, claiming that a Cyclegard valve was "just like" a Cycle Stop Valve.   A 6" Cyclegard valve by Danfoss Flomatic was installed.  Problems immediately occurred from the speed control needle valve clogging with sand.  Also the reaction time of the Cyclegard valve was too slow, and the pressure switch would bounce the pump off and on.  

Several attempts were made to solve the problems to no avail.  Since the nursery owner had several Cycle Stop Valves functioning perfectly, he ordered that the Cyclegard valve be removed and replaced with an original Cycle Stop Valve of the same size.

The Cycle Stop Valve does not have needle valves, as it does not need speed controls.   The fast reaction time of the Cycle Stop Valve also keeps the pump from bouncing on and off when the  flow rate in the field is changed.  The following is a picture of the Cycle Stop Valve installation and the background shows happy trees receiving a dependable supply of water.

1504

Pumps, Wells, Tanks, Controls / Community Pressure Tank "Exploded"

« on: August 05, 2008, 04:29:55 PM »

A Community Water System in north Texas had a big problem.  Their 15,000 gallon pressure tank blew up.  The pictures do not do justice as they were taken several months after the fact.  The cinder block building containing the pressure tank was completely destroyed.  The end of the steel tank that is missing, actually flew into the overhead electric lines and shorted out the electricity for the entire community.  A newly installed air compressor on the tank that was not adjusted properly is taking the blame.  However, many things can cause a tank to explode.  

Thank goodness it happened in the middle of the night, and when no one was around or it could have caused injury or even death.

Power was restored and the debris was trucked away but, the community was still out of water.  A 15,000 gallon pressure tank is not a stock item.  So it would be several months before a new tank could be procured.  In the interim, a 4" Cycle Stop Valve and an 80 gallon diaphragm tank were used to control the 400 GPM fresh water pump.  The CSV and 80 gallon tank have a combined retail price of less than $3,000.00.  A new 15,000 gallon pressure tank installed is going to cost the community close to $50,000.00.

After several months of working on the CSV with the 80 gallon tank, the community is very pleased with the results.  The pressure is more constant than before, and the electric bill is still relatively the same.  The CSV and small tank were installed in a small adjacent building, so a big building, which will also be expensive to construct and heat, has not needed to be built.

There is an above ground tank that stores plenty of water to be used as needed.  So the supply pump, with CSV, and small pressure tank are required to deliver varied flow rates at a constant pressure.  Of course the CSV does a good job of this, as it can supply as little as 5 GPM in the middle of the night, to as much as 400 GPM during times of peak demand, while maintaining a constant pressure.

There really is no need, and the community does not want to replace the 15,000 gallon tank.  Not only are they afraid of the potential explosive hazard but, they do not want to spend upwards of $50,000.00 on a water system that is working better than ever before.

The problem is, the State of Texas is decades behind the technology available.  I have tried many times since 1994 to explain this technology to State of Texas Engineers, as well as State Representatives.  I don't want to say that they can't understand this simple technology but, they certainly do not care to even try.  I have been told many times that this system looks really good but, legislation would have to be changed before they could even consider it.

In the meantime, huge pressure tanks are exploding, countless gallons of water are being wasted to leaks in the system, and millions of dollars are being wasted on huge pressure tanks and water towers, that are no longer needed.

I wonder if the Texas State officials have ever read the "Mission Statement" that they send out with every licence and document.

                                  The Mission of the Texas State Government

"Texas State Government must be limited, efficient, and completely accountable.  It should foster opportunity and economic prosperity, focus on critical priorities, and support the creation of strong family environments for our children.  The stewards of the public trust must be men and women who administer state government in a fair, just, and responsible manner.  To honor the public trust, state officials must seek new and innovative ways to meet State Government priorities in a fiscally responsible manner".

Texas State Officials DO NOT seek new and innovative ways but, actually REJECT new and innovative ways without justification.  Even though the rules allow for variances to test new and innovative ways, I have been informed in writing that the State of Texas will not issue a variance to try a system with a pressure tank of less than approved size.

What happens now is that when a State Inspector comes by this community water system, it will not pass inspection because of the small pressure tank.  Then the city will have to beg for grant money, as they cannot afford the $50,000.00 + price for a new huge pressure tank.  The system will work as is for several years, while grant money is being procured.  Then tons of money that could have been better used on roads, schools, and other things needed, will be used to return the water system to an outdated control system.  I cannot even give the name of this community or they will be tracked down immediately and forced to spend lots of money reverting back to the old way of doing things.

This is just one of many systems that this has happened to in the last 15 years.  Texas is not the only state which has this problem.  Montana has had plenty of opportunities to test new technology over the years, and still Montana State engineers refuse to come to the 21st century.  

It is public money that our public servants are wasting, because of their lack of knowledge.  Don't accept their standard answer that it is not in the rules.  The rules for the State of Texas were written in the 1950's.  We have come a long way since the 50's, shouldn't our government officials be forced to keep up?  Or do we just continue to let them keep wasting our money and our fresh water supplies?

1505

Pumps, Wells, Tanks, Controls / Three Phase Motors, Single Phase Power

« on: July 30, 2008, 07:42:52 AM »

In Europe there are huge restrictions on the high volume domestic use of the traditional concept of VFD's due to EMI and harmonic controls. Single phase into a 3-phase diode bridge rectifier introduces very high triplen harmonic distortion and this is a key area for the power supply companies and general "energy Efficient building' trend to focus on. It requires large inductors or other mitigation techniques to reduce the harmonics and then there are the filter techniques for the High Frequency interference levels. All the restrictions add huge amounts of cost into the traditional methods of frequency control.

1506

Pumps, Wells, Tanks, Controls / Three Phase Motors, Single Phase Power

« on: July 30, 2008, 07:42:16 AM »

VFDs are being incorporated into a lot of home appliances now. They are just using small 3 phase motors. Most appliance motors are custom made anyway, so they just make them 3 phase. Not a big deal really.

1507

Pumps, Wells, Tanks, Controls / Three Phase Motors, Single Phase Power

« on: July 30, 2008, 07:41:40 AM »

I expect IGBTs must have some advantage over thyristors otherwise why are we putting up with them "killing windings & bearings".
Yes I read several books on Tesla, what a facinating character. I wonder how he would utilize the advances we have today.

1508

Pumps, Wells, Tanks, Controls / Three Phase Motors, Single Phase Power

« on: July 30, 2008, 07:40:58 AM »

Yes, OEMs are volume users of VFDs. Washing machines and HVAC - especially air conditioners are huge applications. And, a whole new generation of jacuzzis is emerging.

If VFDs are tough on motors? You bet. The earlier thyristor designs and GTO designs had slow switches. The new IGBT ones are much faster and kill windings and bearings. It is so bad that that is my main occupation nowadays. I will even be running a seminar on bearing problems (EMD) caused by VFDs this fall (sorry, in Sweden - and in Swedish, so it won't of any use to you fellers).

You don't seem to have anything against my mentioning about the two-phase thing? Actually, that is how induction motors started. Tesla's first system was a two-phase, 90 degree system. So the thought isn't really new. But newish.

1509

Pumps, Wells, Tanks, Controls / Three Phase Motors, Single Phase Power

« on: July 30, 2008, 07:40:14 AM »

The evolution of VFDs has certainly been interesting, I remember being blown away the first time I saw one over 40 years ago, before that it was either DC or very expensive Schrage motors. Is it just me or are the modern VFDs much harder on motors than the early SCR based designs, I don't recall special motors or cable length as an issue even 20 years ago.

BTW, how many 3 phase VFD motors do you have in your house? I have a F&P washing machine with no gearbox. The 3 phase 28 pole permanent magnet motor directly coupled to the agitator swishes back and forth just like a regular washer only without all the mechanical clanking.

Regards

1510

Pumps, Wells, Tanks, Controls / Variable Flow Irrigation

« on: July 23, 2008, 11:04:55 AM »

> To; Cary Austin--Cycle Stop Valves
>
> I would like to thank you for your great site.
> It has helped me a loads in improving
> my design plans for typical mixed irrigation
> systems that have so very different needs
> in the flow dept. As you know typical
> landscape irrigatiion systems have high
> volume gpm zones for turf and zones for
> say keeping a hundred new sabal palms
> alive and drip zones that commonly dont
> need all the water the pump can produce.
>
> cycling was a big problem until I discovered
> your cycle stop valves. now one zone can
> suck up all the juice the pump can deliver
> and only lope along at quarter output for the
> next zone and so on withhout the damn
> thing cycling itself to death
>
> again thank you--read all your respones
> to your critics in the letters section of your site.
>
> very informative and well written. I have to
> do a lot of writing to get things done and
> you learn to recognize really good stuff
> when you see it. very balanced and bullshit
> free--you really do know how to sock it to em
>
> -
> Kent McCoy landscape architect

1511

Pumps, Wells, Tanks, Controls / Poor System Performance Solved

« on: July 22, 2008, 12:48:46 PM »

I installed your product last month and I am very pleased with the results. It was easy to install and delivered superb operation out of pump system that I always considered replacing with another well and pump when the money became available.($3000)  But I purchased your valve after finding your info on the net and for less than $200 my problem with poor system performance was solved.
 
 
Thank you
William  Davis

1512

Pumps, Wells, Tanks, Controls / Constant Pressure Pump (propaganda)

« on: July 17, 2008, 08:14:45 AM »

I understand the marketing pressure that pump installers and the public are under to believe these things. Every trade show or Continuing Education Class (CEU) we go to, is inundated with “variable speed pumps”. I can understand this at the trade shows, as that is where companies go to peddle their latest wares. The CEU classes are supposed to be non promotional. However, they teach “variable speed pump classes” like it was something mandatory. After a few classes about how to sell up, using the latest technology to deliver “city like constant pressure”, while saving energy, and being more “green”, anybody would start to believe it. I fell for it myself!

It just takes a few years before you start to realize who is really benefitting from so called “variable speed technology”. I am afraid it is not the end user, the installer, or the environment, it is just the manufacturer.

The more money that is spent promoting a product, the more leery you should be. Products that make a lot of money for the manufacturer, get lots of money spent on promotion.

I have no doubt that some are trying to do the best job possible for the customers. I have no doubt they believe Constant Pressure Pumps will reduce energy and save the environment. Most Drillers and Pump Installers are very reputable people. We are usually hard working and honest people, which can also make us a little gullible. So when the company we buy product from and trust, is wining and dining us, and sending us on cruises for certain amounts of sales, all the while telling us this “newest” product is going to save the environment, we usually fall for it. Manufacturers are just taking care of themselves, while the end user pays for it, and the installer takes the blame for it. A little research is much better than reading the glossy advertisements.

1513

Pumps, Wells, Tanks, Controls / Constant Pressure Pump (propaganda)

« on: July 16, 2008, 02:20:22 PM »

--------------------------------------------------------------------------------
Those of you who do get stuck with a variable speed pump and end up replacing $1100 controllers too often, remember that the Cycle Stop Valve is the only real VFD or constant pressure pump repair kit. We have been replacing every "new" model of variable speed pump that has come out for 15 years, and it looks like we will have plenty to keep us busy in the future.

1514

Pumps, Wells, Tanks, Controls / Constant Pressure Pump (propaganda)

« on: July 16, 2008, 02:17:41 PM »

--------------------------------------------------------------------------------



Of course I always see the worst cases.  By the time they call me, the customer is tired of being out of water and paying too much to keep a VFD system working. So where you have been to the Franklin classes and experienced the hype associated with Variable Speed Pumps, I see all the ones that didn’t work and made the customer angry. I am sure the truth is about in the middle of these two differing opinions, however even in the middle, these type systems aren’t lasting long. Most of the younger people these days just don’t realize that pump systems can last 15, 20, even 30 years without any problems. Just like a lap top computer, everybody thinks that if the pump system last 5 years, just throw it away and get a new one. Warranty of a Cycle Stop Valve has never been an issue, as most of the ones installed 15 years ago are still running.

The Franklin units DO NOT ramp up to the exact flow needed to produce constant pressure. They have a go/no go switch instead of a transducer. The only time they stay on at any speed, is when you are using max flow from the pump and the little switch cannot open. Any flow rate less than maximum, and this switch makes and breaks about 45 times per minute, or two million times per month. This also means that the check valve is opening and closing two million times per month. This alone should ruin the check valve but, you are right that spinning the check while the pump is spinning 4700 RPM instead of the standard 3450 RPM, would also ruin a check valve. If you haven’t seen the water in these little tanks become stale, then either the pump is not holding constant pressure as it should, or the pump is not lasting long enough for the water to even get stale.

 I hear more people with quotes like the following.

“I think I told you we have friends who are on their third VFD system in 4 years at the tune of $1100 a crack each time the VFD control panel got zapped.” Mickeysz

I don’t want to go into all the negative side effects of variable speed, such as harmonics and stray voltage, voltage spikes, resonance frequencies, and other things. These problems get a little over most peoples heads, especially when they don’t even understand little things like the fact that the switch can make and break two million times per month.

I know pump guys like to sell VFD systems because they are a high dollar item. Pump guys who have had a few more years experience with VFD’s, understand that making a few extra bucks now, can cost them customers in the long run. Nearly all of CSV’s best customers, have already been through the VFD stage. Constant pressure is a good thing, you just need a dependable way to produce it.

1515

Pumps, Wells, Tanks, Controls / Constant Pressure Pump (propaganda)

« on: July 16, 2008, 02:15:55 PM »

--------------------------------------------------------------------------------
The following is typical of what many pump installers believe after listening to the manufactures.  I hope this helps clear up some of the misinformation that is causing some people to fall for a Constant Pressure Pump.  The principle is so technical that even the pump installers do not understand.  I am sure they think they are selling you the best technology available.  You should study the facts before making that decision.  Doing what the pump manufacturers recommend is not usually what is best for the end user, just for the manufacturer.

from  Driller
Junior Member   Join Date: Jul 2008
Posts: 6
"Constant pressure pumps work great, we have sold hundreds of them. They aren't a new concept they have been out for 15+ years going back to the old Hays Pumps days." Driller

You are right, variable speed pumps are an old concept going back about 30 years. The "old Hays Pump Days" were only about 10 years ago, and none of them are still working.

Then came the Grundfos SQE. These pumps are still on the market after 9 years but, there have been so many upgrades to that system that I can no longer count them. The latest upgrade makes the pump cycle on and off like a standard pump for 1000 cycles, to see if it can again regain communication with the motor before faulting out. This is probably the best of the variable speed pumps available. However, only a tiny fraction have lasted 9 years, and the average life is less than 4 years. BTW, none of the upgraded stuff works with the older stuff so, if you have a problem, the whole thing has to be replaced.

Then came Franklins CP Water, which had water running through the electric controller to try and keep it cool. These were only 7 years ago and everybody in the industry knows these didn't last very long. Next was the Frankin Sub Drive in the black box about 5 years ago. Apparently the black colored box was the reason these units were getting hot and failing so quickly, so after a year or so they started painting these boxes white. This change about 3 years ago was supposed to keep the controllers from overheating. Reports from the field show that the white boxes quickly turn black and even discolor the wall they are mounted on.

In the last 3 to 5 years there have been many other brands of these variable speed controllers come and go on the market. Problems with cooling, low flow, communication, voltage spikes, and many other things have made these type systems unreliable.

Since you agree that variable speed pumps are "not a new concept", you should be aware that the Cycle Stop Valve has been replacing these variable speed pumps for about 15 years now. This makes the Cycle Stop Valve the most advanced technology available. Since 1993, when Cycle Stop Valves first started replacing variable speed pumps, every time a VFD system is discontinued, it has been replaced with a CSV.

"Read this press release from 15 years ago that I found on this website called xxxx this proves that constant pressure (CP) has come along way." Driller

I don't see anything about constant pressure on this web page except for the ConstaBoost for centrifugal pumps, they make no mention of the Sub Drive or Mono Drive. Maybe this company has already learned their lesson about constant pressure pumps.

"The CP controller converts your 1-phase power to three-phase (which three-phase is cheaper to run on) It is variable speed and ramps up and down depending on your demand."Constantpressure

A 3 phase motor is a little more efficient than a 1 phase motor but, the heat losses of the VFD itself, the loss of motor efficiency running on current with harmonic content, and the 40 watts of power used by the VFD when the pump is not even running, more than add back any energy saving that could have been available from varying the speed.

"A standard pump just kicks on full blast until it can shut off. The standard pump when it kicks on runs twice the amperage and slams the pump, motor, pipe, & wire against the well casing when it torques on." Driller

Actually starting a standard pump against a Cycle Stop Valve delivers the same reduced amp soft start as when ramping up the speed slowly with a VFD. 

I have heard a lot more problems with rubbing holes in the pump, motor, and wire, from the two million switches on and off per month, that happen when the system is controlled by the Franklin Drive, because it has a small bandwidth pressure switch instead of a pressure transducer.

"Constant pressure pumps require a much smaller tank which saves you money.
CP pumps because they run on three-phase you are able to use smaller wire which can be a huge savings." Driller

A CSV uses the same small tank as a CP pump. However, all the water in this small tank can be utilized with the CSV, while the CP pump has such a small pressure bandwidth, that it does not allow any of the water in the tank to be used. This means that a CP pump must start for every glass of water or even to fill the ice maker. It also means that any water in that tank gets stale and contaminated, and this does not happen with the CSV. Using a three phase motor so you can reduce the wire size, only helps a little with the extra cost of the VFD controller.

"They save power, you could say they are more "Green" than a standard pump." Driller

A CP pump DOES NOT save energy, compared to the energy reduction of a standard pump being controlled by a valve. To say that CP pumps are more "green" is incorrect. Actually the energy used to manufacture these computerized controllers exceeds any energy savings that might have been saved by there use.

"The only problem ever had with the constant pressure pumps were the check valve they put in the head of the pump. The checkvalve was cheap and the water coming out so fast and spinning right out of the pump would ruin that spring." Driller

I am sorry but, spinning is not what is wearing out the check valves. The switching on and off of the pump by the "pressure sensor" of the Sub drive, which can happen about two million times per month, is also opening and closing the check valve two million times per month, which equals check valves not lasting very long.

"Don't get me wrong constant pressure pumps aren't ideal for every situation I just wanted to clear some things up because ALOT of people want to knock the pump systems with little or no knowledge of them and without ever installing or owning one." Driller

I am knocking the "Constant Pressure" pumps because I have A LOT OF EXPERIENCE with them. I was building and installing them about 20 years ago, and can go back 40 years if you want a real history lesson. We have had so many problems with Variable Speed Pumps, that we devised the Cycle Stop Valve to replace them about 15 years ago. Ever wonder when the "old Hays Pumps" failed, what was used to replace them. We have been replacing every brand of variable speed pump or controller with Cycle Stop Valves for 15 years now. Everyday we use Cycle Stop Valves to replace SQE's, Sub Drives, Mono Drives, Balance Flows, Aquavars, ABB's, Toshiba's, Allen Bradley's, AC Tech's, and countless other brands of Variable Speed Pumps and controllers.

The people who use Cycle Stop Valves everyday, are those who have already been through a dozen different VFD pumps, with the promise that the newest model will solve all the problems of the previous models. They finally realize that VFD's are just "hype" designed to increase profits for the manufacturer, and reduce the life expectancy of the equipment (planned obsolescence). They soon realize that the Cycle Stop Valve is the newest and most beneficial technology available to deliver "Constant Pressure" dependably, and at an affordable price.

I would be happy to discuss any of these or other questions you might have, either here on the forum or personally.
Thank You
Cary Austin
800-652-0207