Any Electricians in the House?

[Kali]

I know this is strange but you are such a diverse group. I need a new 3 horsepower motor for a piston pump on a heavy duty long distance water system. My old fried one says PH 1 type CDR B Duty

This catalog I am looking at lists motors as brake, 3 phase, split phase, and capacitor (and the prices vary hugely between types). Any way to tell which my old one is?

[Wilber_Stool]

1. Lets see

PH 1= single phase
CDR= capacitor direct run?
B duty= intermittent duty

That's pretty close. Three hp, that's big bucks.

[tech3149]

2. It should be

single phase (PH 1) capacitor. I assume it's on a 110 volt circuit? Could be 220 volt also. Are those the only markings you have?

[TexasProgresive]

3. I agree with the 1st two posters

my guess is that it is 220vac, single phase, capacitance start. By the way are you sure the motor is toast? We have a well with a submersible pump that has a capacitor in a control box above ground. These caps go bad regularly we've replaced ours about 4 times in 20 years. They are a whole lot cheaper then a motor.

If the starter cap is mounted on the motor it will be a bulge or round case that is on the outside casing of the motor-the wiring carrying the electricity to the motor will enter there. One other thing to look at is the contactor relay that turns power on and off to the motor. In my system it is pressure operated. When the water pressure drops to 20PSI the pump is turned on; at 50PSI it turns off. Since you are pumping water from a distance it might use some other factor. Good luck to you, Kali. PS. Be sure that the power is off and no one can turn it on when working on the wiring. Turn the breaker off and put a piece of tape over it until you are through working on it. House currant is a killer.

[Kali]

5. Thanks, here is what I can tell you....

(boy do I know its some bucks! - this is the third HUGELY expensive thing to go wrong this week)

Its 22o, its a motor that runs a belt driven pison pump that pushes the water on up a pipeline AFTER the 550ft + deep 3 horse submersible gets it out of the ground! Its primarily for livestock water, but our old 25 foot hand dug well here at the house needs has been needing supplementing for the past couple years every week or so or no laundry gets done!

some other stuff the motor has on it is 60 Hz 1750 rpm, it does NOT have the little rounded humpy thing some electric motors have but it does have a square box the wiring goes into that has the two cylindrical things that I guess are capacitors (and that is pretty much where my electrical knowlege/understanding ends.)

No contactor thing that I can see - we turn it on and off at the breaker.

Had the well guy back out to look at it and he said it was fried - didn't have one on the truck, and suggested Grainger - that's what I'm looking at.

(Just replaced the one IN the well, this was a heartbreaker)

Has your pump lasted 20 years????? the one we just replaced barely made barely 12 years...arrrggg

[TexasProgresive]

7. Submersible pumps have no set lifetime

They can go bad in 5 years or last 50. That guy may be right. The capacitor will be marked with it voltage capacity and micro farads which is the amount of capacitance. A question- when you throw the breaker do both the well pump and this one try to start at the same time? When a motor is started especially of this size, it is a real strain on the electical system to provide power. They use a huge amount of current starting. This may be part of your problem. The drop in voltage and extended time to get the motors running at speed may be decreasing their lives.

We traditionally have our unplanned big expenses come in November.

[Kali]

9. oops

sort of replied about turning both motors on below.

Our unplanned huge expenses come when funds are low! Wait!... come to think of it they come when we feel like we are finally getting ahead too....just the universe keeping us humble I guess.

The well guy said the shortest (barring idiocy) was 6 years and the longest he knew of was 23 years. I had heard 10 - 12 was about normal. At least it didn't quit in may or June when the ponds are dry. (Actually the well pump got done in less than half a day. This part is taking longer - might be an argument for having a spare motor, yeah right!)

[Stew225]

4. make sure you remove your

shorts first.

[phaseolus]

6. Couple references --

Motor Technical Reference, from Leeson
http://www.iprocessmart.com/leeson/leeson_technical_reference.htm

pdf file, "What do all those things on a motor nameplate mean?" from Allen-Bradley
http://www.ab.com/manuals/dr/Motors/Motors9_2.pdf

Your motor might be what's called a "Definite Purpose Motor" which means it's a special animal designed specifically for heavy duty long distance water systems, which means you'll be lucky to find a close match in the catalog you're looking in.

I'm not an electrician & I don't know about water systems, but I am an electrical controls engineer who has to design systems that run pump motors in industrial environments. So I can definitely state a few things:

You don't need a brake motor, or a gearmotor for that matter.

If it's three phase, the power cable going to the motor will have three conductors plus a green-insulated ground conductor. If you have fewer conductors than that, it ain't three phase. Check the old motor's nameplate for a wiring diagram. If it's not there take the cover off the "peckerhead" (small box where the power goes in) and look inside the cover for a wiring diagram. Compare with your catalog.

If I was involved in replacing an existing motor for a pump, the easy way would be to have the salesman find an exact match or look up his line's closest cross-reference. A couple things that must be taken into account when specifying general-purpose motors for pumps: Motor dimensions and mounting - the "frame size" and the design of the motor where the shaft comes out must be the same as the old motor or they wont' fit together. Speed -- Fast motors have a synchronous speed of approx 3450 rpm, give or take a few, and slow speed motors have a speed of 1725, more or less. For pump applications you can't interchange one for the other or you'll have half the flow you need or you'll trip circuit breakers or something. Ditto for horsepower. And of course the voltage must match your supply voltage. And environmental considerations -- see the "construction" discussion on page 7 of the pdf file.

In my job I always, always see general-purpose three phase motors that can be connected to 230 or 460 VAC, which require protection by an overload relay or some other means, so I'd also have to consider the implications if the Full Load Amps of the new motor was different.

Since I'm guessing yours is a "definite purpose motor" you can probably forget most of what I said in the last two paragraphs...

[Kali]

8. wow

again thanks, and thanks to DU for being there - this is such a great community.

We will be taking the whole set up to another pump guy in "town" because with the bad luck we've been having we are worried about the piston pump too and want to have him check it out. So I get what you are saying re: mounts and such. I just wanted an idea what this was coing to cost then the types got me curious...I have a mental wall when it comes to electricity. Can't seem to absorb any of the concepts, its weird. (vehicle repairs are the same - as soon as it becomes "electrical" I can't deal with it, can barely use a curcuit tester! (only can see if its "live" have no clue what the measurments mean and no matter how often its explained it doesn't soak in) It often seems like magic to me and so I have a certain fear as well.

Both pumps come off a regular breaker box right at the meter, they are the only things on it. (that's two breakers for the pumps and the main for all the power) I would say most of time the pump in the well runs twice as much as the piston pump and when the piston is running they both are. They are not on the same switch (we just use the breakers) but I know I have turned them on at the same time lots of times - are you saying I sould wait till one gets going before turning the other on? Oh and there are only two wires plus the ground (three total)

and now to check your links...