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Author Topic: Well pump starting help  (Read 21860 times)

europachris

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Well pump starting help
« on: April 10, 2006, 01:29:41 AM »
Hi, everyone.  This isn't a strictly Lister question, but I'm having a problem starting my well pump with the generator.

Here's some pics of the setup: http://www.power-co.net/ilchris.htm.

It is a Changfa 185 engine and a Markon 3.2 KVA, 2 pole generator end.  The generator is rated for 13.3A at 240V and 26.6A at 120V.  It's a brushless design unit.  The drive system is industrial "L" section, 6 rib belt and pulleys.

I ran it up on 120V with about 2500 watts of load, part of that being a ShopVac, and it didn't even grunt.

I installed a Gen-Tran transfer switch yesterday, and hooked everything up that I'd like to keep powered during an outage, including the well pump.  The well pump is a Franklin 3/4 HP, 2 wire, 240V pump.  It's down about 140 feet.

So, to test the pump, I run the generator up to about 3650 rpm, which is about 1900 on the engine.  I have all transfer switch loads off, and hit the pump breaker.  The meters both peg for each leg and the generator loads down a bit, and the pump just grunts and won't start.  I'm not sure if the drive belt is slipping or not, but it's properly tightened.

I know it's all wired correctly and I'm getting solid 240V from the generator.  The pump is rated at 6.5A running current, so I have double that from the generator, not taking into account starting currents.  The generator should be good for 26A at 240 for peak motor starting.

I didn't put a meter on the line to see how far the generator loaded down, as I didn't want to fry the pump or blowout the thrust bearing, but it's definitely loading down by judging how the few electronic ballast fluorescents dimmed down while trying to start the pump.

Looking at the Franklin literature, it does appear my generator is marginal for starting a 2-wire, 240V pump.  If it was a 3-wire pump I'd be OK.  Not knowing the difference between 2 and 3 wire, 240V pumps (not 1 vs. 3 phase, either), I don't know if there is anything to add (like the motor starting 'boosters') to help out the starting of the pump.

It's kind of a bummer, as that was the whole reason I built this generator up.  The gen head I already had for several years at another house, but needed a bigger engine to get the most of it.  Now it appears that I need a bigger gen head to go with the 185!

Thanks for any help, gang!

Chris

Jim Mc

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Re: Well pump starting help
« Reply #1 on: April 10, 2006, 03:27:44 AM »
2-wire pumps use split-phase motors.  3-wire pumps are capacitor start.  There's a significant difference in the starting current between the two.  I had the identical problem with my first generator, a 3 kW 3600 rpm genset, and changed the well pump to a 3-wire (also Franklin Electric motor), and the problem cleared up. 

If you're so inclined, you could try and fiddle around with some power factor correcting capacitors.  Start out with 50 uF or so across the 240V supply to the well, and see if there's any improvement.  Get a clamp on ammeter, and measure the aggregate current (well + capacitors).  See if adding the caps reduces the current draw.  Maybe try 100 uF.  Use motor run caps, as opposed to motor start caps. 

But, if you're the type of guy that'd rather be turning wrenches than probing 240 V circuits, just get a bigger generator!  (come on, you know you want it...)

BTW, the 3-wire pumps also have more starting torque, so they're the best type to use, if you don't mind running the extra conductor and installing a pump control box.


europachris

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Re: Well pump starting help
« Reply #2 on: April 10, 2006, 01:51:28 PM »
2-wire pumps use split-phase motors.  3-wire pumps are capacitor start. 

--->Thanks for the info, Jim.  I was doing some more research last night and found that an "N" code motor, which is what my pump has, pulls 108 amps per horsepower for starting.  I've got 3/4 horse, so that comes out to about 80 amps.  Now, Franklin says my pump has 40.8 locked rotor amps.  That doesn't equate.  Nevertheless, I've got a 13.3 amp at 240 generator, and even if I can get double that for motor starting, I'm 14 amps short.  A 5kw gen head *might* get me the peak power I need, but maybe not, and I'm not too willing to spend the $$$ to get one and find out it won't work.  I got this 3.2KVA head REAL cheap from Markon, new in box, as it was surplus, some years ago.

Installing a 3-wire pump would be the best bet, but that would require new wiring from the house out to the well, the new pump, etc.  Since the pump is only 4 years old or so, that just doesn't make sense, either.

We're not out in the boonies, so *hopefully* we would be OK without water for a while as long as we have power to run the furnace in the winter and run fridges/freezers to keep food cold.  I plan to store up a 5 gallon jug just for those sorts of emergencies.  We also don't have much in the way of ice storms, tornados, etc. (northern Illinois) but we do get some nasty stuff that could shut power down for a day or two.

I'm just bummed as most of the reason I put in the transfer switch was to get 240 into the house to run the well pump.  Well, at least it turned out to be a real nice installation, and having the other circuits able to power up the lights, TV, fridge, etc. works really well.  I just figured by seeing 6.5A running current on the well pump data plate on the pressure tank that I'd have enough oomph to start it.  Guess not!

Thanks again.

Chris

europachris

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Re: Well pump starting help
« Reply #3 on: April 10, 2006, 03:37:17 PM »
Just a little more info - digging into some tech bulletins from Franklin, they state the starting watts for my pump at 9600!!! :o  Granted, it's only for 1/2 second, but that's 3 times what my gen head can produce.  So, I might as well throw a dead short across it!  Running watts is only about 1800, so I'm fine there.

I would wonder if a 5kW head could do it (if it could make 10kW at surge), but the 185 engine wouldn't have the horsepower to sustain it past the intial jolt from the flywheel inertia.  If the generator got behind the power curve, it wouldn't be able to recover and keep the pump running.

I'm not thinking the capacitor across the pump leads is going to fix my issue.  I've simply got a current hog of a pump and really need a R195/10kw setup to run it, which is way bigger than I need otherwise.

chris

fuddyduddy

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Re: Well pump starting help
« Reply #4 on: April 10, 2006, 03:55:46 PM »
A good 5 KW ST head would start it without effort with that engine.

Tom

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Re: Well pump starting help
« Reply #5 on: April 10, 2006, 05:53:10 PM »
For future refference, Grundfos makes a SQFlex line of pumps that will run of AC or DC with no change of wiring. The one I am running on my system is a 5 gpm with a 300' lift. This should be similar to what you need. These pumps soft start  and eliminate the surge requirement. They also use about 50% of the electricity (it's designed for solar) due to it's impeller design. The one I have runs about 450 watts. The only down side is cost as the run over a grand.
Tom
2004 Ashwamegh 6/1 #217 - ST5 just over 3k hours.

europachris

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Re: Well pump starting help
« Reply #6 on: April 10, 2006, 07:07:21 PM »
Neat!  I'll have to look into those. 

Of course, as is so typical today, our house has the 'low cost option' installed - 240V 2-wire.  I'm not hoping it burns up any time soon, but it would be nice to have a pump that is more alternative power friendly.

I'm looking into a larger gen head for my setup, something on the order of 5KVA, and that would get me the 40A/240V surge capacity needed to start the hog.  An ST head would work, of course, but that would require I scrap most of what I have together due to size, weight, and drive requirements.  I've got a call into the local Markon sales office to see about a BL series head larger than what I have now.

Of course, that said, it would have likely been easier to sell the head I have, eliminate the need to buy the expensive Browning industrial drive system, and just get an ST-5.....still might, too....

Chris

Andre Blanchard

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Re: Well pump starting help
« Reply #7 on: April 10, 2006, 09:33:19 PM »
Neat!  I'll have to look into those. 

Of course, as is so typical today, our house has the 'low cost option' installed - 240V 2-wire.  I'm not hoping it burns up any time soon, but it would be nice to have a pump that is more alternative power friendly.

Here is what I consider an alternate power friendly pump.
http://www.aermotorwindmills.com/pumpjacks.htm
Connect any kind of power you have to it, even the kid.

Some of you may enjoy this pic I found while searching for the pump jack stuff.
http://www.worldofstock.com/closeups/PMO1921.php
Just what you need to help rebuild the Lister.;)


Back to the pump.  One thing you could try with your current setup.
  Get a 240 volt motor, one with good ball bearings that spins easy, put a heavy pulley or flywheel on the shaft.
  Start the generator, then start this flywheel motor, you may need to do the old rope start on the flywheel to get it started.
  Then once the flywheel motor is up to speed and the generator has settled down start the well pump, the flywheel motor should help generator with the surge load from the pump.
___________
Andre' B.
______________
Andre' B

rgroves

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Re: Well pump starting help
« Reply #8 on: April 10, 2006, 09:44:43 PM »
 


Some of you may enjoy this pic I found while searching for the pump jack stuff.
http://www.worldofstock.com/closeups/PMO1921.php
Just what you need to help rebuild the Lister.;)


I don't think that's a cold start model.  No, i'm sure it isn't.
But you are THE MAN for giving us the link.

rg
A country boy can survive - Hank Williams Jr.

Procrustes

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Re: Well pump starting help
« Reply #9 on: April 10, 2006, 10:15:21 PM »
I'm in the same boat.  I average well under one kW load so I don't want a big generator.  So the question is how to manage peak loads.

Perhaps my best idea yet is this.  Hook up a gast air motor to your genset driveshaft via a sprag clutch or the like with a governor to maintain RPM's.  Drive it with a big air tank.  Gast sells 2.5 and 5HP models, IIRC.  Air motors are extremely simple, but I've heard they are sensitive to moisture.

Another thread here discusses an analagous use of batteries and a DC motor to handle peaks.

On another topic, it's a shame that that poor country girl can't afford a proper pair of shorts.

GuyFawkes

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Re: Well pump starting help
« Reply #10 on: April 10, 2006, 11:28:10 PM »

Back to the pump.  One thing you could try with your current setup.
  Get a 240 volt motor, one with good ball bearings that spins easy, put a heavy pulley or flywheel on the shaft.
  Start the generator, then start this flywheel motor, you may need to do the old rope start on the flywheel to get it started.
  Then once the flywheel motor is up to speed and the generator has settled down start the well pump, the flywheel motor should help generator with the surge load from the pump.
___________
Andre' B.


that is actually really clever...
--
Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

solarguy

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Re: Well pump starting help
« Reply #11 on: April 10, 2006, 11:56:06 PM »
It is clever!  It's the same parlor trick as "rotary" three phase converters, just a motor that is willing to pump watts back into the circuit under certain circumstances.

Finest regards,

troy

Doug

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Re: Well pump starting help
« Reply #12 on: April 11, 2006, 02:47:08 AM »
Motor loads on power systems actualy can feed a lot of power back into a system if there is enough inertia behind them. As Andree sugested you can use a three phase motor for this but they're not self starting. You can start 3 phase motors on single phase power but it requires a timer, some capcitors and tricky wiring ( I could post this information, but it will involve, some crayons and an hour of typing ). Large Single phase induction motors will also work but then your back to square one with another motor you can't start.

So in one case or the other you may need to build your own reduced voltage starter for the helper motor to start.
More crayons required to get into detail on this....

Try the pump first, I bet it will start with all the inertia in the Lister/ST combo
Failing this get a smaller pump...

Doug

rsnapper

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Re: Well pump starting help
« Reply #13 on: April 12, 2006, 09:30:02 PM »
She can work on my motor anytime!   ;D

Jim Mc

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Re: Well pump starting help
« Reply #14 on: April 13, 2006, 12:35:01 AM »

  ...Get a 240 volt motor, one with good ball bearings that spins easy, put a heavy pulley or flywheel on the shaft.
  Start the generator, then start this flywheel motor, you may need to do the old rope start on the flywheel to get it started.
  Then once the flywheel motor is up to speed and the generator has settled down start the well pump, the flywheel motor should help generator with the surge load from the pump.


Won’t work.  Here’s two reasons:

1.  Operating an auxilary motor in this fashion is a basic induction generator.  The problem with induction generators is that they can deliver power only to loads that operate at a leading power factor.  A motor starting up, such as the well pump, presents a lagging power factor to the source.  Thus, the induction generator doesn’t have the ability to deliver power to the intended load.

2. Induction generators only deliver power into a network if they are driven at super-synchronous speed.  But, as we all know, induction motors normally operate with some slip, and thus  turn at sub-synchronous speed.  So, let’s say your aux motor is humming along at 3450 rpm (about 4% below synchronous speed in a  60 Hz system), it can’t begin to deliver it’s full rated power until the network (in this case your 3 kW generator) slows down to 8% under the nominal 60 Hz.  I’m pretty sure the flywheel and governor on the Changfa is gonna keep the generator speed fairly constant duting the starting event. 

As I mentioned earlier power factor correction capacitors are the only hope, short of getting a bigger generator or 3-wire pump.