Pump troubles - confused

[truta11]

I've been cycling my Hayward 1.5 hp inground pump by hand to save on electricity costs. A few days ago I went to turn it on, and it would not start, but would just give 60 Hz hum. The rotor turned freely, so I decided to change the start capacitor. After changing the capacitor, the motor started briefly but didn't reach full speed, and shortly after returned to 60 Hz hum with no rotation. The motor itself then started to smoke. The motor had been running for no longer than 10 seconds when that happened. I thought that was strange, but decided that the motor had just finally decided to short out in the armature.

I replaced the Hayward with a no-name 1.5 hp pump. It was labeled as a White River 1.5 hp inground pump, but I can find no documentation or support for it anywhere. Anyway, upon installation, the pump sounded terrible, did not seem to reach full speed, did not prime, and threw the breaker within 5 seconds or so of starting. I reset the breaker, checked everything over again, and tried again. This time it started to smoke before it threw the breaker, again within 5 seconds.

Two pumps having problems and smoking motors on the same system? The first pump had operated for years without a problem, and I'm sure that I wired the new one correctly. I thought there must be a system problem, so I checked for obstructions in the piping. Everything looks clear. I checked the supply voltage. 230 V, 60 Hz as it should be. Both pumps were configured for 230 V operation. The system is set on a 20 A 230 V breaker, with about 6 feet of lead from the pump to the breaker.

Any idea what could cause two pumps to fail? Am I just unlucky? Anything else to try before I set up a new pump and blow that one too? Any other ideas?

Thanks in advance.

 

[Divin Dave]

Wierd. It might just be a concidence, but things like this are almost too hard to belive, but its possible.

The only thing on the power side that could cause the problem that i know of, is if somehow you dropped a leg of the 230V.

Check your voltage at the input and output side of the breaker and verify its 230 on both sides. Thats about all I could recommend. Maybe someone with more electrical knowledge will chime in too.

 

[Kiss4aFrog]

Number one, do NOT install another motor until you find a fault or all you'll do is damage a new motor and waste your time, effort and $$$

Your problem is something happened to the wiring with the first motor. The second motor is just confirming that. The second motor isn't a second problem, just a confirmation of the first.

It is NOT anything in your plumbing. You should make sure the impeller is wet when you flip that breaker just to protect the plastic but even if you plugged the intake and discharge with solid plugs the motor should start and run up to speed for a good period of time (minutes) before even thinking of tripping the breaker. If yours is tripping in seconds it's not a plumbing issue it is a voltage/amperage issue with the wiring.

This might be something you want to get an electrician for. Only say that because it doesn't seem to be something that's visually evident. Like you say it ran fine for years and you manually controlling it shouldn't have created any new issue.

I'm assuming you were tripping the switch inside the timer ??

Where did you take the voltage reading ??

Did the motors have one capacitor or two ??

"six feet of lead for the pump motor to the breaker" - That would be the sub panel ?? Did you inspect the pump motors breaker in the main panel ?? Is the wiring continuous all the way to the sub panel or are there any junction/outlet boxes where the wires might be spliced and wire nutted. If so, would want to check those too.

 

[Kiss4aFrog]

What specific motor did you have and what specific motor did you install ?? Hayward and White River don't really say much. Just wanted to look them up to see if anything sticks out.

 

[truta11]

Thanks for the replies so far. I will check the power both before and after the breaker and will let you know what I find. By the way, I forgot to mention that I did check both legs independently, and they were both 115 V and 60 Hz.

To answer the other questions:

I took the voltage reading at the end of the wires where they connect to the motor. I tested them unconnected, so there was no load to pull the voltage down or anything.

The 6 feet of lead is to the pool subpanel. The main panel has a 60 A breaker to the subpanel. There are no junction boxes between either panel or between the subpanel and pump, as far as I know. I have a toggle switch installed under the subpanel that turns power to the pump on and off. I did not install the switch, it was like that when I bought the house. I did find today that it appears that the switch only disconnects one leg, but I still need to confirm that. It is a three-position switch, and it didn't seem to be disconnecting the power correctly. In the neutral position I still had 90 V or so and 120 Hz showing at the leads, and with the switch in the 'left' position it was 115 V, I don't recall the frequency but want to say it was 60 Hz. In the 'pump on' position it was 240 V and 60 Hz. The doubled frequency of the neutral position makes me think of two multiplied sinusoidal signals. It's strange in any case. I would think the pump would still be trying to run under 120 V and 90 V, but it always seemed to be powered off. I've also been very energy consumption conscious and haven't noticed a lot of power draw with the pump off. Maybe the toggle switch just geeked out and caused all of my problems.

And finally, the previous pump was a Hayward Super Pump II 1.5 hp. The new pump was a White River AC IMP1500.

I'm going to check the subpanel breaker and that goofy switch within the hour and will let you know if I find anything out.

And no, there is no way I'm hooking anything else up until this is solved.

 

[truta11]

Ok. I found and corrected a problem, but I don't know if it was the problem.

The voltage from the main panel checked out ok. 243 V total, 60 Hz, 50% duty cycle. 121.5 V, 60 Hz, 50% duty cycle to each leg. The voltage leaving the breaker was 243 V, 60 Hz when on, and 700 mV AC with 0 Hz displayed frequency when off.

As I suspected, the toggle switch was a single pole double throw, so there was always one leg energized to the pump. I guess it wouldn't ever turn on because the ground isn't in the motor circuit. I double checked each leg and the total voltage with the toggle switch in each position. Here are my results:

Toggle Position 'Pump On'

Red to Black - 244.3 V, 60 Hz, 50% duty cycle
Red to Ground - 121.5 V, 60 Hz, 50% duty cycle
Black to Ground - 122 V, 60 Hz, 50% duty cycle

Toggle Position 'Off'

Red to Black - 72.6 V, 60 Hz, 50% duty cycle (frequency would sporadically jump up to 90 Hz, then back down to 60 Hz)
Red to Ground - 121.6 V, 60 Hz, 50% duty cycle
Black to Ground - 32 V, 60 Hz, 50% duty cycle

Toggle Position 'Unused Branch'

Red to Black - 106 V, 60 Hz, 50% duty cycle
Red to Ground - 121.8 V, 60 Hz, 50% duty cycle
Black to Ground 0.7 V, 60 Hz, 150-180 Hz, 50% duty cycle

So the toggle is obviously not working well. With the power off, it behaved properly with a continuity check. No continuity to either side when in the middle, only continuity to one alternating branch when alternating position. It must breakdown under higher voltages.

I removed the toggle from the circuit, so that the red and black from each half of the pump breaker go directly to the pump. I double checked everything again and found it to be correct. 240 V at the breaker in, 240 V at the breaker out, and 240 V at the pump end of the wires, with 120 V in each leg. Switch the breaker off and it goes to 0 V at the pump end of the wires. No shorts to ground from either leg.

So, clearly the toggle would have been goofing up the pump while I thought it was off, as I always had at least 72.6 V across the windings. I still don't understand why I wouldn't have heard it trying to do something. I also don't understand why I would get a bad result with the toggle in the 'Pump On' position, since then I should have had the proper voltage applied to the pump.

Any theories out there, or is it time to call in an electrician? Any way to check the circuit under load? My current thought is to reassemble my Hayward and give that a go. Too bad I took it all apart.

 

[mgarf33]

As for the 72v, check it again with your meter on LoZ function, and you may have your answer.

As for the bad result in the on position? That's hard to say, but it sounds like you had low voltage on one leg. When you switched the pump on, the current wasn't steady. Don't know, just a guess on that one.

Here's another wild guess. Someone went cheap on the GFCI and didn't buy a proper double pole. Maybe just installed 1 or 2 single pole GFCIs.

Did someone connect a GFCI receptacle to one leg of the circuit and neutral to ground?

Are you getting interference from the bonding wire?

Btw, why are you checking duty cycle? Is it a PWM controller?

 

[truta11]

That's an interesting thought. I suppose I could have had AC coupling through the toggle switch, which is why it would pass AC voltage when I didn't want it to yet still show an open circuit with a DC continuity check. That's a moot point at this point, since I've removed the toggle switch from the circuit completely. I also don't have a low impedance setting on my meter.

The GFCI looks fine, and there is no neutral in a 240 V circuit.

Since I don't have an oscilloscope I checked the duty cycle as my way of making sure that I was getting a clean sine wave. I know that just because I got 50% duty cycle doesn't necessarily mean that it's a clean sine wave, but it's something.

I'm not sure what you mean by 'Are you getting interference from the bonding wire?' Could you explain?

 

[mgarf33]

The GFCI looks fine, and there is no neutral in a 240 V circuit.

Yes, I'm aware of that, yet I find 120v circuits branched off of a dedicated 240v circuit using the ground as a neutral far too often.
The reason I ask so many questions about the GFCI is that they will also show ghost voltage when tripped. Hence, suggestion to check with LoZ.

I'm not sure what you mean by 'Are you getting interference from the bonding wire?' Could you explain?

The frequency fluctuation had me scratching my head, thinking the ground or bonding wires may be picking up some RF or something.
Now that I think about it, it sounds like a full wave rectification circuit would cause your 120Hz reading. Whether it be inside the switch, your multi meter malfunction or elsewhere...salt cell power supply maybe??.

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