I do not have a well, and not a water expert, but I have a recurring water leak problem and thought I'd share my experience in case it helps. I recently experienced a problem similar to what you described - water kept running but nothing I could touch was leaking. I could hear water running (high pitch sound), but could not locate the leak. I finally checked under my house, in a crawl space, and it was very wet. It turned out that the leak was underground in a rusty old galvanized pipe. I am still cursing that P.O.S. and the fact that any fool ever used galvanized rust prone metal.
One other way I've been able to detect water leaks is by using a cheap stethoscope. I once had a very expensive plumber come out with an electronic stethoscope attached to a read-out, but since then have been able to narrow in on leaks in walls by using the stethoscope (and saving myself about $1000 / event).
Was the motor replaced with the same size (horsepower, amperage, voltage) motor? What is the amperage and voltage listed on the motor's data plate? In many cases the motor plate will either list the size of the required breaker, or if not, the manufacturers website will have that information available. If you "had the motor changed" it might be best to call the company that changed it and report that the new motor is tripping the breaker, where the old one did not, and have them check for issues, since they should have verified that the new motor would work the same, or made any changes needed to support any change in the motor. If you changed it yourself, that's on you.
You should not replace the breaker with a larger breaker unless the new motor requires a larger breaker.
You should not replace the breaker with a larger breaker without ALSO replacing the wire with larger wire, suited to the size of the larger breaker, which should be suited to the size of the new motor. 20 amp, 12 gauge copper, minimum - 30 amp, 10 gauge copper, minimum.
Rather than "sanding the wires" you should (with the breaker off, of course) cut off the damaged ends of the wire, pull it a little further in, and strip the ends to get new undamaged wire. If this is not possible, consider replacing the wire, especially if it's fairly short run.
110V (single-pole breaker?) is rather abnormal for most well pump installations. One potential fix would be to re-wire for 220V operation if possible
Best Answer
The 1.5HP rating is the mechanical output power of the motor, not the input electrical power. The way these motors are specified is that they put out rated power at rated current and frequency when consuming the full-load amps. Your naive current calculation fails to take into account motor efficiency and power factor. In other words, the real calculation goes like this:
V * I = P / (eff * PF)
Where V is the operating voltage, I is the current, P is the rated output power, eff is efficiency, and PF is power factor. If you solve that equation for I, that is your expected current. But there is no need to go through the math, because the full load current is already listed on the nameplate as 9.2A. So if everything is working right, and the motor is putting out 1.5 HP, you would expect to see 9.2A.
Still, even though your expectation of 6 or 7A is wrong, it sounds like the motor is consuming more than the full-load current. It is unclear from your post whether this is something new, or if it has been doing this ever since it was installed.
I can think of three reasons you would draw more than rated full-load amps. Reason one is that the pump is running at a higher flow rate and lower pressure than it was designed for. (It may be counter-intuitive, but centrifugal pumps and blowers consume MORE power when there is less back pressure... they consume the least power when the back pressure is highest in the no-flow condition).
The second reason is that something is faulty either in the pump or the motor. Maybe the pump shaft is rotating in the wrong direction or a bearing has worn out.
The third reason is that the voltage is too high and the motor is simply being over-driven.
If you have the make and model of the pump, and know the total vertical head that the pump is working against, we could maybe narrow it down a bit more by comparing your operating pressure against charts in the pump datasheet. It would be good to know if the voltage was 250 at the time you measured the current.