Submersible pump drops circuit breakers

[tinytec]

Five years ago we switched from our deep well water supply to city water. The water/sewer rates have since increased enough so we could save at least $400 a year by switching back to the deep well.

I tried to use the pump but it delivers water for only about 1/2 minute to 3 minutes, then trips the 30 amp breakers. If I reset the breakers it will pump up pressure to the 60 PSI cutoff point.

The pump is a 3-wire Model CBC4005X4D, 1/2 HP, 230 volts, 4.7 amp. with a Franklin Control box. The storage tank is a Sears 85 gal bladder type.

Everything in the control box seems to work OK. The relay opens when the pump starts and the capacitor checks OK with an ohmmeter.

I disconnected the three pump wires and measured the resistances: yellow - to red: 16 ohms; black to red: 20 ohms; yellow to black: 5 ohms.

Are these resistance measurements typical for this pump? Is there any way to check the pump otherwise?

Thank for any help!
Fred in NYS

[Bob NH]

http://www.franklin-electric.com/Manual/AIM_13.htm

Winding resistances are about right. I suspect that your pump is in bad shape from sitting so long. It will draw more current if there is a lot of friction or if the impellers are jammed up.

Someone with a clamp-on ammeter could measure the current but you know it is already too high. If you had a meter, you might try starting it several times and see if it improves, but that might accelerate the damage.

You can often replace just the pump part (the least expensive part) if you pull the pump.

There could be a lot of silt in the well, or stuff just crudded up after all those years. You might have to get some work done down the hole.

[speedbump]

Does this control box have one capacitor or two?

bob...

[tinytec]

Thanks for the reply and guidance.

I connected an ampmeter in series with each 120 VAC line to the pump. The white line draws only about 5 amps, but the black line draws 25 amps. That's what is dropping the 20 amp breakers.

Does this mean one of the motor windings are partially shorted?

I sure hate to dig up the well. The head is 6 feet down and somewhere along an 8' path - and to make matters worse
it's under my wife's favorite 30-year old rose bush!!

Fred

[speedbump]

Do you mean an in line amp meter?

Bob was referring to a clamp on meter. They open up so you can put them around the wire to read amps.

If you put an amp meter on the black, red and yellow, you will get three different readings. None should be as high as 20 though. If you use a clamp on meter, you want to check the yellow wire. That one should match the max amp reading on the name tag of the control box. If you check the two wires at the pressure switch before the control box, the readings should be the same.

bob...

[tinytec]

Bob,

There is only one 50 ufd. 220 VAC capacitor.

I measured the current load on each wire by inserting an amp meter in series and turning the pump on just long enough to get a good reading: Yellow: ~25 amps; Black: ~25 amps. Red: ~ 5 amps.

As this puzzle gets deeper more observations and questions come to mind:

1. Why doesn't the overload protector drop out before the 20 amp breaker opens up? Should all three connections on the circuit protector read as "0" ohms?

2. The cable coming from the pump has three wires and each one is black - there are no yellow or red wires. The installer (before we owned the house) appears to have identified the wires by stripping different lengths of insulation from each wire at the control box connections. I listed the resistance measurements for each wire by assuming the wire colors were based on the connector labels in the control box i.e. "red", "white or yellow" and "black".

3. There is no ground wire with the pump cable, only the three black wires! The control box and pressure switch are grounded to each other and to the house electrical ground.

4. The resistance readings between the wires (disconnected) are red-to-yellow: 16, red-to-black: 20, and black-to-yellow: 5 ohms. Is it possible that two of the wires are interchanged and the start winding is always energized? I'm thinking something like the 16 and 20 ohm windings are "run" windings and the 5 ohm is the start winding. The relay points do open immediately at startup.

5. Why does the pump run at random durations anywhere from less than a minute to several minutes before tripping out - if there were a constant short or whatever why wouldn't the run cycle be about the same every time?

It would sure be nice if all this info helped you to spot a problem other than a bad motor.

Thanks again for your time!
Fred

[speedbump]

Bob,

There is only one 50 ufd. 220 VAC capacitor.
That's the start capacitor. You must not have a run cap. That's fine.
I measured the current load on each wire by inserting an amp meter in series and turning the pump on just long enough to get a good reading: Yellow: ~25 amps; Black: ~25 amps. Red: ~ 5 amps.
This might be the problem. If the red wire still has amperage on it, this tells me the relay is bad. The relay should remove the start cap and the start winding form the circuit as soon as the motor comes up to speed. In which case the red wire would be 0 amps. What color is the relay? And what does it look like? It will be the only other part in the box beside the overload protector.

As this puzzle gets deeper more observations and questions come to mind:

1. Why doesn't the overload protector drop out before the 20 amp breaker opens up? Should all three connections on the circuit protector read as "0" ohms?
Maybe the breaker is weak, or maybe someone bypassed the overload. All three connections should read 0 while touching any two terminals, if it is not tripped.

2. The cable coming from the pump has three wires and each one is black - there are no yellow or red wires. The installer (before we owned the house) appears to have identified the wires by stripping different lengths of insulation from each wire at the control box connections. I listed the resistance measurements for each wire by assuming the wire colors were based on the connector labels in the control box i.e. "red", "white or yellow" and "black".
That makes your job a little more exciting.

3. There is no ground wire with the pump cable, only the three black wires! The control box and pressure switch are grounded to each other and to the house electrical ground.
The pump may be older than the new electrical code for submersible pumps.

4. The resistance readings between the wires (disconnected) are red-to-yellow: 16, red-to-black: 20, and black-to-yellow: 5 ohms. Is it possible that two of the wires are interchanged and the start winding is always energized? I'm thinking something like the 16 and 20 ohm windings are "run" windings and the 5 ohm is the start winding. The relay points do open immediately at startup.
The readings (not counting the resistance of the wire to the pump) should be Yellow to black 4.2 to 5.2. Yellow to red 16.7 to 20.5. Max amps with motor running should be 5 amps (Yellow or black) Red 0.0.
5. Why does the pump run at random durations anywhere from less than a minute to several minutes before tripping out - if there were a constant short or whatever why wouldn't the run cycle be about the same every time?
I can't answer that one. I don't have the heart to do that to a motor. Locked rotor amps is 23 amps. This indicates the motor is not running. Have you checked the wires to ground yet?
It would sure be nice if all this info helped you to spot a problem other than a bad motor.
I wish I had some better news for you.
bob...

Thanks again for your time!
Fred

[tinytec]

I measured the current load on each wire by inserting an amp meter in series and turning the pump on just long enough to get a good reading: Yellow: ~25 amps; Black: ~25 amps. Red: ~ 5 amps.

This might be the problem. If the red wire still has amperage on it, this tells me the relay is bad. The relay should remove the start cap and the start winding form the circuit as soon as the motor comes up to speed. In which case the red wire would be 0 amps.

The red wire still has amperage on it because it is in series with the relay coil, which is picked throughout the pump cycle, and keeps the start circuit disconnected.

What color is the relay? And what does it look like? It will be the only other part in the box beside the overload protector.

The relay is a black plastic unit, about 1 1/2" square, with three push-on connectors. I removed the cover to see the coil and points are working OK.


1. Why doesn't the overload protector drop out before the 20 amp breaker opens up? Should all three connections on the circuit protector read as "0" ohms?

Maybe the breaker is weak, or maybe someone bypassed the overload. All three connections should read 0 while touching any two terminals, if it is not tripped.

All three connections read "0". Overload appears to have original wires soldered in place.

2. - - -

3. - - -

4. - - -

5. Why does the pump run at random durations anywhere from less than a minute to several minutes before tripping out - if there were a constant short or whatever why wouldn't the run cycle be about the same every time?

I can't answer that one. I don't have the heart to do that to a motor. Locked rotor amps is 23 amps. This indicates the motor is not running. Have you checked the wires to ground yet?

The pump delivers a full stream of water so is it safe to assume the rotors are not locked? The wires measure about 2.5 megohms to ground.

I wish I had some better news for you.
bob...

Looks like we have a major well dig coming up when the ground thaws here in the northeast.

Thanks again for your time and all the help! This is a great forum!
Fred

[speedbump]

The red wire still has amperage on it because it is in series with the relay coil, which is picked throughout the pump cycle, and keeps the start circuit disconnected.

The red wire isn't in line with the relay coil. It is connected to the start winding in series with the start cap. If the points don't open when the motor starts, the coil is bad.

[tinytec]

"The red wire isn't in line with the relay coil. It is connected to the start winding in series with the start cap. If the points don't open when the motor starts, the coil is bad."

>>>There are two red wires to the relay in this control box. The points do open when the motor starts. Everything seems to ensure a dirt-dig and well hunt this spring (aarrggghhh).

Thanks again!
Sad Fred

[speedbump]

Fred, the relay you have must be the old voltage sensing relay. Black in color, one screw will remove the cover. Is this what it looks like and are these the points you say are opening?

If so, there should be a yellow red and orange wire attached to 1, 2 and 5. 5 being yellow, 2 red and 1 orange which connects to the start cap. If you have anything different, it may be wired wrong or maybe someone used the wrong colored jumpers. Since the sub cable isn't colored, I guess this could be the norm.

bob..

[tinytec]

Fred, the relay you have must be the old voltage sensing relay. Black in color, one screw will remove the cover. Is this what it looks like and are these the points you say are opening?

>>>That's it Bob - black, one screw.. .

If so, there should be a yellow red and orange wire attached to 1, 2 and 5. 5 being yellow, 2 red and 1 orange which connects to the start cap. If you have anything different, it may be wired wrong or maybe someone used the wrong colored jumpers. Since the sub cable isn't colored, I guess this could be the norm.

>>>I previously made a diagram of the wiring and it's wired as you describe except my diagram says the #1 wire is also red.

Fred

[speedbump]

You have got me there. All the ones I have ever seen are that way. Nobody uses 1/2hp pumps in this area except me and they are all two wire motors so I don't have a box to look at. Maybe the 1/2hp is different for some reason.

bob...