Reading 310 volts on a 120 240 volt residential system

snoogins1236 said:
Readings were at the junction box above the well pump, yes motor was running at time of readings.
Click to expand...

Since this thread meandered, it is probably worth a bit of a summary.

You posted pictures of the equipment in post 38

Reading 310 volts on a 120 240 volt residential system

I leave plumbing to those who know how. My cousin is a master plumber. I call him with plumbing he calls me with electric. Easy peezy! That's sort of the issue that gets me involved. ECs do their thing, plumbers the other, but you really have to work both. What I find mostly is "pump guys"...
forums.mikeholt.com

One of the photos clearly shows that what goes to the motor is Hot (L2, Yellow), Hot (L1, Black, via relay), Start (Red, via capacitor).

The main motor winding is connected black to yellow, and should get 240V between these two wires (sometimes 120V for smaller motors). The start winding is is powered via the capacitor to get a phase shift. This phase shift is _necessary_ to start the motor spinning in the correct direction, but is not needed once the motor is running. When the motor is just starting, the voltage is supplied from the relay to the capacitor to the motor; once the motor is up to speed the relay opens, and the voltage is whatever the motor happens to generate on the now unconnected start winding.

The video in post 42 shows the voltage in a similar system.

Reading 310 volts on a 120 240 volt residential system

I do? You literally just said "the capacitor is producing the increased voltage", which it's not, but...... Glad it's fixed. But it is. All fixed
forums.mikeholt.com

The only thing confusing about your report is that you have 120V and 310V, not 240V and 310V. To totally nail this down you would need to take all 6 measurements (Black-Yellow, Red-Black, Red-Yellow, Black-Gnd, Yellow-Gnd, Red-Gnd). However if the pump is working I'd say you don't need to fully nail this down, and just say 'The 310V is not unexpected and the pump is working, so all is fine.'

-Jonathan
 
winnie said:
Since this thread meandered, it is probably worth a bit of a summary.



The only thing confusing about your report is that you have 120V and 310V, not 240V and 310V. To totally nail this down you would need to take all 6 measurements (Black-Yellow, Red-Black, Red-Yellow, Black-Gnd, Yellow-Gnd, Red-Gnd). However if the pump is working I'd say you don't need to fully nail this down, and just say 'The 310V is not unexpected and the pump is working, so all is fine.'

-Jonathan
Click to expand...
I don't see the point in a summary but there is NOT a neutral, he only thought it did. Any 120V readings would be from the ground. Which brings another point from his pics in which apparently the EGC was optional that day.... As in not connected to the party in the disconnect.

Taking measurements inside the control box is not very practical because as the OP found out, they are designed in a way that nothing is connected when the hood is off, and that is on purpose, because of that exploding capacitor.

Generally I will just take my pump readings at the well head which gives me enough data to know what's going on 95% of the time. Usually current brings more information than voltage.
 
fastline said:
I don't see the point in a summary but there is NOT a neutral, he only thought it did. Any 120V readings would be from the ground. Which brings another point from his pics in which apparently the EGC was optional that day.... As in not connected to the party in the disconnect.

Taking measurements inside the control box is not very practical because as the OP found out, they are designed in a way that nothing is connected when the hood is off, and that is on purpose, because of that exploding capacitor.

Generally I will just take my pump readings at the well head which gives me enough data to know what's going on 95% of the time. Usually current brings more information than voltage.
Click to expand...
I don't think those are pictures from his project. He couldn't post his.
 
fastline said:
I don't see the point in a summary but there is NOT a neutral, he only thought it did. Any 120V readings would be from the ground. Which brings another point from his pics in which apparently the EGC was optional that day.... As in not connected to the party in the disconnect.

Taking measurements inside the control box is not very practical because as the OP found out, they are designed in a way that nothing is connected when the hood is off, and that is on purpose, because of that exploding capacitor.

Generally I will just take my pump readings at the well head which gives me enough data to know what's going on 95% of the time. Usually current brings more information than voltage.
Click to expand...
The purpose of the summary was to be helpful to the OP and those that will come on this discussion at a later date. Something you have failed to do so far.
 
  • Like
Reactions: MTW
ActionDave said:
The purpose of the summary was to be helpful to the OP and those that will come on this discussion at a later date. Something you have failed to do so far.
Click to expand...
Would it also then be helpful or antagonistic to bring up the concerning mention of "neutrals" and 120V, when there is nothing in any of the circuits to support that fact? Like any EC would both read what is on that disconnect, and simply open it know there is no neutral there. To be right honest, this is more like a homeowner type thread than an EC.
 
fastline said:
Would it also then be helpful or antagonistic to bring up the concerning mention of "neutrals" and 120V, when there is nothing in any of the circuits to support that fact? Like any EC would both read what is on that disconnect, and simply open it know there is no neutral there. To be right honest, this is more like a homeowner type thread than an EC.
Click to expand...
If that is a consideration there is the Report button that can be clicked and it will send an alert to the forum moderators who will consider the content of the thread and decide if it should remain open. As of yet no reports have been sent, as such the thread is open for discussion so that the OP and anyone else can learn.

The electrical trade is broad and no one comes to this forum with the same experience and not everyone uses the same terminology or practices the same level of detail when approaching a problem.
 
You must log in or register to reply here.
Top