Submersible well pump ( Capacitors shelf life ? )

[Davebones]

My well pump is little over 10 years old . 120 ft deep 1 1/2 hp . No issues but I am going to replace the start / run capacitors as a PM . Thought about buying a couple of spares to have on hand incase one went bad . Just curious what the shelf life is for these type capacitors ?

 

[Dennis Alwon]

There is a lot of info on the web about this but I would check with the manufacturer of the particular product you are going to use.

Many manufacturers specify a typical shelf life for a capacitor or an assembly containing capacitors. The manufacture's stated shelf life for an aluminum electrolytic capacitor can range from 2 to 10 years, depending on the quality of the component

 

[K8MHZ]

There is a lot of info on the web about this but I would check with the manufacturer of the particular product you are going to use.

2 to 10 years for electrolytics. He will probably be using a dry dielectric which can practically last forever. You are spot on about the type and checking it out with the manufacturer if there is any question.

 

[gar]

210730-1220 EDT

The professor that authored the book on AC Machinery that I studied from was the inventor of the single phase capacitor run motor. Inventor because a patent was issued. Developer is probably a better description. And the major development was that of a capacitor for the phase shift. This invention was the result of a request from Detroit Edison for development of a motor for refrigeration purposes.

It should be noted that this type of motor runs from a single phase source, has no brushes or other major wear problems, can be completely sealed, and has a better power factor than a comparable three phase motor.

I never met Bailey, but I believe he was still alive when I came to the U of M. His coauthor was Gault who was younger, but died before my time at Michigan. I did know Gault's wife when she was a secretary at the Electronics Defense Group.

The capacitor run "single" phase induction motor was really a two phase motor with an integral capacitor to provide the necessary phase shift. In turn the development of the capacitor start and run motor made it possible for Tecumseh Products, of Tecumseh, Michigan, to build a completely sealed refrigeration motor and compressor. I have one of those in my freezer that has been running for at least 50 years without ever having been serviced.

Also it should be noted that Bailey was a coworker with Henry Ford in the mid 1890s at the Edison Illuminating Company in Detroit. Henry was chief engineer at that facility, but not a formally educated engineer. Henry was truly an engineer, and in a number of fields.

I have some Sprague electrolytic capacitors from the 1960s that are still good. And some others that have had continuous power applied for 50 years.

.

 

[kwired]

A capacitor made 50 years ago might still be good today, but the question might be will a similar specification capacitor built today last for 50 years?

 

[gar]

210730-2352 EDT

kwired:

An electrolytic capacitor manufactured today can be better than a good one made 50 years ago. Technically one should be building better ones today because we know more, and I suspect there are better ones. If you do not get good quality, then it is because you re not buying quality. The combination of consumer demand, and what is technically possibly determines what is available.

I will comment on wire insulation which does not directly relate to electrolytic capacitors.

GMI ( General Motors Institute ), possibly renamed Kettering Institute in Flint, Michigan is doing some research on magnet wire insulation. In other words what goes into motors. The breakdown voltage of wire insulation is not a constant relative to V/unit thickness, but rather decreases as thickness increases. GMI is researching ways to reduce this degradation factor. This is being done by using many different layers of thin dimension to produce a thicker layer that has a total breakdown voltage more directly proportional to total thickness.

.

 

[kwired]

210730-2352 EDT

kwired:

An electrolytic capacitor manufactured today can be better than a good one made 50 years ago. Technically one should be building better ones today because we know more, and I suspect there are better ones. If you do not get good quality, then it is because you re not buying quality. The combination of consumer demand, and what is technically possibly determines what is available.

I will comment on wire insulation which does not directly relate to electrolytic capacitors.

GMI ( General Motors Institute ), possibly renamed Kettering Institute in Flint, Michigan is doing some research on magnet wire insulation. In other words what goes into motors. The breakdown voltage of wire insulation is not a constant relative to V/unit thickness, but rather decreases as thickness increases. GMI is researching ways to reduce this degradation factor. This is being done by using many different layers of thin dimension to produce a thicker layer that has a total breakdown voltage more directly proportional to total thickness.

.

True we do learn and improve things over time. We also find ways to do things more efficiently or more cost effectively and sometimes that comes with compromises in other areas. So that leaves your saying we can make them better being the main truth there.

 

[paulengr]

I would not keep spare motor capacitors.

First off look up capacitor reforming. What a pain. Not all need it but some do.

Second 60 years ago things were not engineered and computer designed. So everything was overbuilt to compensate.

An electrolytic capacitors is a couple pieces of aluminum foil sandwiched with absorbent paper (Bounty??) soaked in a liquid electrolyte. Even glycol (antifreeze) will worked. The whole thing is wound into a tight coil and stuffed in a can that is crimped shut to save space. It does expand and contract a little with temperature so the can does have to breath slightly. Over time the electrolyte dries up. This decreases the capacitance over time and also decreases the flash over voltage. The capacitor eventually fails typically in 8-10 years. Either it arcs over or the capacitance loss and longer starting times eventually destroys it.

 

[Davebones]

I went ahead and replaced the whole Franklin control box . Box costs $138 it would have cost that much for the 2 capacitor's and relay . Old box was installed in 2007 so the capacitor's were at least 14 years old . There was some crud starting to come out of one of the capacitor's . I'll just give it a couple of years and then buy two spare capacitor's . Thanks for everyone's input I appreciate you guys sharing your knowledge ..

 

[Buck Parrish]

My well pump is little over 10 years old . 120 ft deep 1 1/2 hp . No issues but I am going to replace the start / run capacitors as a PM . Thought about buying a couple of spares to have on hand incase one went bad . Just curious what the shelf life is for these type capacitors ?

I thought that it was built into the pumps now a days. All the pumps I've installed, I never put an external capacitor. The replacement well pumps I've installed that had an existing external one , I always by-pass it when I install the new pump. I disconnect it.
Am I missing some thing ?

 

[Davebones]

These are in the control box beside the well bladder tank installed when the pump was replaced in 2007 . It has two capacitors, relay , two overloads , terminal strip in it . All the wells I've seen around here have all the components in the box . Pump is a submersible 120 ft down .

 

[Dzboyce]

Dave, I replaced a 1 hp submersible pump last week. It was installed in 1998. The homeowner had replaced the start capacitor the day before. Didn't solve the problem. It was the thermal overloads built into the motor.

Homeowners want to solve pump problems by replacing the capacitors and/or the pressure switch.

Over 90% of the time when a capacitor goes bad on a submersible pump, that's the symptom, not the actual problem. The actual problem is the pressure tank is bad. The pump has short cycled enough times to blow out the capacitor. It will blow the new capacitor out again until the pressure tank is replaced or recharged.

And no, I don't replace just the capacitors. I replace the e tire control box. It costs, more for me to trouble shoot it than to replace it, when you factor in my labor rate.

Buck, in the submersible well pump world, there are what we call 2 wire and 3 wire motors. The 2 wire motors are a maximum of 1 1/2 hp. They do not use a control box, they have a capacitor and centrifugal relay built into the motor. 3 wire pumps utilize an above ground control box. At a minimum it has a start capacitor and a solid state start/run relay. A 1 1/2 or larger will also have a run capacitor. Over 2 hp, you have the option of a 2 pole relay, with the pressure switch controlling the relay.

 

[Buck Parrish]

Thanks for the info, now I know.
..........
That's a pretty big pump for 120 feet. We'd probably have used 3/4 hp. Bet that 1 1/2 hp makes a lot of water pressure.

 

[Dzboyce]

Thanks for the info, now I know.
..........
That's a pretty big pump for 120 feet. We'd probably have used 3/4 hp. Bet that 1 1/2 hp makes a lot of water pressure.

Yeah a 3/4 puts out enough water for a house, but they like to irrigate yards in Florida. Here in Eastern Washington, we rely completely on irrigation for lawns and gardens. We get less than 10 inches of precipitation annually. It's not uncommon to install a 20 to 50 gallon per minute pump for a residence here.

 

[Buck Parrish]

Yeah a 3/4 puts out enough water for a house, but they like to irrigate yards in Florida. Here in Eastern Washington, we rely completely on irrigation for lawns and gardens. We get less than 10 inches of precipitation annually. It's not uncommon to install a 20 to 50 gallon per minute pump for a residence here.

Thanks good to know. How far do you have to drill? 250 feet ? Otherwise the bigger hp pump might would be irrelevant. Also does the state require a ' amount used' meter?

 

[kwired]

Thanks for the info, now I know.
..........
That's a pretty big pump for 120 feet. We'd probably have used 3/4 hp. Bet that 1 1/2 hp makes a lot of water pressure.

Most them will build similar pressure, the higher HP units are generally needed to pump more volume, how much lift is needed is a factor in determining what size pump is needed though, that lift is from water level in the well not from level where pump actually sits in the well.