I let the smoke out of my shallow well pump......

[RogersJetboat454]

I have a couple of questions for the electrical guru's out there, but first I will start off with my story.

We dashed up to Maine today for me to set up the water in the camp. Mom wants to be able to use the cottage Memorial day weekend with out having to bucket flush the toilet (I am working as a favor for my co-worker that weekend's Saturday, so the soonest I would have been up there is that Saturday night). Anyway, got up there. Pulled the cement cover off the well. Got the lines filled with water and connected, yada yada yada. Got every thing together and fired up the pump. Pump runs for 30-45 seconds then POOOFFF smoke comes out of the switch box on the side of the motor.
The pump mean while doesn't break stride, keeps running normally, but I shut it down anyway. I figured I may have burnt up the contacts in the rocker switch built into the side of the pump. Not so!! Turns out I let the smoke out of what I assume to be the starting capacitor View attachment 93929.

If you look to the right, you can see a crack in the plastic casing, and a spot at the bottom where the plastic got hot and melted into a little bogger.

I assume my failure is most likely due to the fact that the capacitor was the cheapest one money can buy. My pump is a Harbor Freight special (3/4hp cast iron shallow well) that I bought 7 years ago, and surprisingly it has served us well for the limited amount we use it. I know some of you may say replace the whole thing, especially considering the same pump is currently on sale for $99, but that ain't me. I want to get every last bit of goodness out of this thing that I can, and I don't consider my self a member of the throw-away society. So after all that here are my questions;

I can get a starting capacitor from Granger and several other sources. How close does the MFD rating have to be to what was present (Capacitor was a 65?F +/- 5% rated at 250VAC)?

Secondly, If I find an acceptable candidate for replacement, is it acceptable to solder and shrink it into place? In my haste to get it out of there to take a look at it, I chopped the wires too short to effectively wire nut it back in. I should have enough wire present to do a good solder job on the stranded wire HF used.

Thanks.

 

[rbh]

Re: I let the smoke out of my shallow well pump......

Never smoking a capacitor (honest never ) all I can say if you are going to solder it together make sure you do not do a cold joint or there will be a wack of resistance.

Lots and lots of heat, let the solder run on the wire not the iron's tip.


(I can't remember with a capacitor if you need to add those heat sink vise grip thingys on each side of the capacitor to protect it for heat kill)

 

[RogersJetboat454]

Re: I let the smoke out of my shallow well pump......

Never smoking a capacitor (honest never ) all I can say if you are going to solder it together make sure you do not do a cold joint or there will be a wack of resistance.

Lots and lots of heat, let the solder run on the wire not the iron's tip.


(I can't remember with a capacitor if you need to add those heat sink vise grip thingys on each side of the capacitor to protect it for heat kill)

Thanks RBH.

Never a cold joint when I solder . I've got a butane fired MAC soldering iron that as the 9th grade exploratory program electronics teacher said "Gets hotter than a fire cracker" (picture that said in a southern drawl). I can probably get the tips of the wires hot and soldered faster than the heat will travel the wire. So hopefully I shouldn't kill the new Cap with excessive heat.

 

[j_martin]

Re: I let the smoke out of my shallow well pump......

Original failure is probably a welded shut starting switch. Cap can take current for a few seconds during starting without overheating. If it stays in the circuit, it'll let the smoke out.

You need to service the starting switch, a centrifugal switch in the end of the motor as well as replace the capacitor.

Is the pump circuit is fused right? It should have blown the fuse/breaker.

 

[rbh]

Re: I let the smoke out of my shallow well pump......

Original failure is probably a welded shut starting switch. Cap can take current for a few seconds during starting without overheating. If it stays in the circuit, it'll let the smoke out.

You need to service the starting switch, a centrifugal switch in the end of the motor as well as replace the capacitor.

Is the pump circuit is fused right? It should have blown the fuse/breaker.

J, the wife thinks you look like RED/GREEN, but do you have an Ontario accent????

 

[Nandy]

Re: I let the smoke out of my shallow well pump......

why not just solder a piece of wire with the matching connectors for the cap? That will save heating up the cap. I have solder many caps but those are meant to be solder. Those starting capacitor, im not so sure... BTW, that is why the motor kept running, the capacitor is just used to start the motor motion. You should be able to get a capacitor anywhere they sell ac motors and parts for it. Get as close as you can. You should be looking at about 5 dollars for a cap of that rating....

 

[bigdee]

Re: I let the smoke out of my shallow well pump......

Original failure is probably a welded shut starting switch. Cap can take current for a few seconds during starting without overheating. If it stays in the circuit, it'll let the smoke out.

You need to service the starting switch, a centrifugal switch in the end of the motor as well as replace the capacitor.

Is the pump circuit is fused right? It should have blown the fuse/breaker.

I agree with j-martin. centrifugal contacts probably corroded over the winter causes it to arc and weld itself closed......correct fuse or breaker size could have saved the cap. Clean the contacts with crocus cloth and replace the capacitor. What is the FLA and SF on the nameplate?

 

[RogersJetboat454]

Re: I let the smoke out of my shallow well pump......

Original failure is probably a welded shut starting switch. Cap can take current for a few seconds during starting without overheating. If it stays in the circuit, it'll let the smoke out.

You need to service the starting switch, a centrifugal switch in the end of the motor as well as replace the capacitor.

Is the pump circuit is fused right? It should have blown the fuse/breaker.

Thanks for the info.
I'll have to look into the starting switch, although If it comes down to it needing to be replaced I think it's going to be the whole shooting match being replaced. Surprisingly Harbor Freight sells all the mechanical parts for the pump it's self (I had to rebuild the pump after the the well went dry on us and the pump ran for a while), but the motor is considered a whole unit replacement not serviceable by the end user. Maybe for grins I will call Harbor freight and see what they want for the motor.

The pump is on a dedicated 15A circuit, and didn't pop the fuse. I should take a look around to see if I can find a 15A fast blow in my stash. Unfortunately screw in fuses are starting to get few and far between.

 

[j_martin]

Re: I let the smoke out of my shallow well pump......

I agree with j-martin. centrifugal contacts probably corroded over the winter causes it to arc and weld itself closed......correct fuse or breaker size could have saved the cap. Clean the contacts with crocus cloth and replace the capacitor. What is the FLA and SF on the nameplate?

Hopefully the cap smoking saved the starting winding. Maybe not.
At this point you have to pull the end cap off the pump motor. If it's been in a wet well house for a few years, you'll probably break off the thru bolts. At that point you can chit can the whole works and go get another one.

If by some miracle the bolts survive, and the starting winding isn't charcoal black, clean up the centrifugal switch, and put it back together with a new cap.

 

[RogersJetboat454]

Re: I let the smoke out of my shallow well pump......

why not just solder a piece of wire with the matching connectors for the cap? That will save heating up the cap. I have solder many caps but those are meant to be solder. Those starting capacitor, im not so sure... BTW, that is why the motor kept running, the capacitor is just used to start the motor motion. You should be able to get a capacitor anywhere they sell ac motors and parts for it. Get as close as you can. You should be looking at about 5 dollars for a cap of that rating....

Thanks for the info. I think I have sourced a capacitor that will work at Grainger (64-77 ?F, part number 2MER7) for $8. We have one in the town I work in, so I'm going to give them a call to see if they have it in stock. It's a name brand Dayton capacitor with male spade connectors on the top, so I will check to see if they have a couple of pre-made female lugs that just clip on, then I can solder the other end to the remainder of the wires I cut. That will save the cap from the heat of the iron. If others are right, I may have bigger issues that caused the original cap to give up the ghost.

 

[RogersJetboat454]

Re: I let the smoke out of my shallow well pump......

Hopefully the cap smoking saved the starting winding. Maybe not.
At this point you have to pull the end cap off the pump motor. If it's been in a wet well house for a few years, you'll probably break off the thru bolts. At that point you can chit can the whole works and go get another one.

If by some miracle the bolts survive, and the starting winding isn't charcoal black, clean up the centrifugal switch, and put it back together with a new cap.

Pump is high and dry under the cottage in a well ventilated area, so hopefully thats not the case. The motor cover is that "miracle material" called plastic , and was apart 3 years ago when I had to take the pump apart to replace the impeller and seals. Taking a look at what HF has for an exploded diagram of this, I'm wondering if this sucker even has a start circuit? Maybe my Cap is a running Cap rather than a starting Cap. See what you think...View attachment 94010View attachment 94011

 

[RogersJetboat454]

Re: I let the smoke out of my shallow well pump......

I agree with j-martin. centrifugal contacts probably corroded over the winter causes it to arc and weld itself closed......correct fuse or breaker size could have saved the cap. Clean the contacts with crocus cloth and replace the capacitor. What is the FLA and SF on the nameplate?

Thanks for the reply. Not sure what you mean by FLA and SF. No name plate on anything.

 

[bigdee]

Re: I let the smoke out of my shallow well pump......

Strange, I did not see a start switch either. What is the MFD of the cap......10 or less would indicate that it is a run capacitor which would be unusual for a motor that has to start under a load. FLA=full load amps SF=service factor since this is a cheapo from HF it probably doesn't matter.

 

[RogersJetboat454]

Re: I let the smoke out of my shallow well pump......

Strange, I did not see a start switch either. What is the MFD of the cap......10 or less would indicate that it is a run capacitor which would be unusual for a motor that has to start under a load. FLA=full load amps SF=service factor since this is a cheapo from HF it probably doesn't matter.

Capacitor was a 65?F +/- 5% rated at 250VAC. According to the HF website, the pump pulls 7 amps max.

 

[rockyrude]

Re: I let the smoke out of my shallow well pump......

I'm not 100% sure of your diagram, but the start switch and winding would normally be inside of #35, what appears to be the main motor. It is normally located in the end opposite where the shaft exits.

 

[RogersJetboat454]

Re: I let the smoke out of my shallow well pump......

#35 is the bladder tank .

All of the bits and pieces of the motor are between #52 and #12. The actual exterior of the motor is #7 (finned aluminum). #2 is the plastic cover that houses the motor along with the capacitor and rocker (on/off) switch.

 

[bigdee]

Re: I let the smoke out of my shallow well pump......

Capacitor was a 65?F +/- 5% rated at 250VAC. According to the HF website, the pump pulls 7 amps max.

That would be a start capacitor! Some motors have a current/thermal start switch

 

[NYBo]

Re: I let the smoke out of my shallow well pump......

J, the wife thinks you look like RED/GREEN, but do you have an Ontario accent????

Um, that IS Red Green in his avatar!

 

[RogersJetboat454]

Re: I let the smoke out of my shallow well pump......

OK....

So if anybody still gives a **** about this post, heres the plan for this weekend.

Plan A View attachment 94562




Plan B View attachment 94563

The capacitor was $8 bucks from Grainger. It's interesting how much smaller it is than the Chinese spec one I blew, maybe thats a good sign? The pump it's self was on sale for $99 bucks. I tossed a 20% coupon down, which knocked it down to $80. I think at this point I'm going to keep it as a spare if the capacitor works.

I used the new pump as an "Iranian blue print" to figure out how the capacitor gets wired into the electrical circuit. This is a diagram of the circuit; View attachment 94564

From what I can tell by doing some homework, this pump seems to use an induction motor. If there is any salt to what the Wikipedia article says about induction motors, the capacitor figures in either two ways; It either starts the motor with an out of phase secondary winding which is shut off by a temperature coefficient thermistor, or the out of phase winding helps start the motor and remains on to improve torque (I'm hoping it's the later).

 

[bigdee]

Re: I let the smoke out of my shallow well pump......

OK....

So if anybody still gives a **** about this post, heres the plan for this weekend.

Plan A View attachment 94562




Plan B View attachment 94563




From what I can tell by doing some homework, this pump seems to use an induction motor. If there is any salt to what the Wikipedia article says about induction motors, the capacitor figures in either two ways; It either starts the motor with an out of phase secondary winding which is shut off by a temperature coefficient thermistor, or the out of phase winding helps start the motor and remains on to improve torque (I'm hoping it's the later).

For 99 bucks it probably is the later. Gota love that Harbor freight even though it is a crap shoot.