Actually, you're not. Put a 240v gen in series with the 240 resi.
The trig identities say you'll get some kind of sine wave at some combo freq at some phase shift out of this.
But. . .stand back.
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Question about Well Pumps
- Thread starter Little Bill
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The trig identities say you'll get some kind of sine wave at some combo freq at some phase shift out of this.
But. . .stand back.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
Those type pumps are non-reversable.
- Location
- San Francisco Bay Area, CA, USA
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- Electrical Engineer
Not only that, but you may end up spinning the impeller right off the end of the shaft and losing it down the hole! Do NOT purposely run a submersible pump in reverse!
I am not sure it is correct, for there is a control box, relay and capacitor for the pump under discussion which means there are starting and running windings for the pump motor. So the pump rotation could be reversed by changing the three leads, unless it is prohibited by its manufacturer.
- Location
- Tennessee NEC:2017
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- Semi-Retired Electrician
This pump/motor has already been pulled out of the ground. Given the fact that it has been sitting idle for 2+ years, and the fact the people are going to rely on this for their water supply, I think a new pump/motor is the way to go here.
But thanks for the reply.
kwired
Electron manager
- Location
- NE Nebraska
To reverse the motor the polarity of one winding must be changed in relation to the other. When these motors are wound there is only three leads extended for user connection, main winding, aux winding and a common lead to both windings. Since not all four leads are extended for user connection these motors are not reversible.
Changing the three leads only puts the capacitor in series with the wrong motor lead.
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hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
In order to reverse a single phase motor, the start or run winding has to be reversed, on this type of motor the start and run winding is connected together at the pump in the well, the other start winding lead is broken through the relay at the top of the well. There are only three leads tied to the motor externally, four leads would be necessacary to reverse, so the windings cannot be reversed. If this was a three phase motor it would be different.
ptonsparky
Tom
- Occupation
- EC - retired
Running a three phase pump backward does give some water. Just wont build a lot of pressure. They can run almost a year or so that way. Don't ask. I did tell them they needed a new pressure gauge.
- Occupation
- Licensed Electrician
No one is going to run the pump that Little Bill is hooking up backward because it is wired through the Franklin control box but you can reverse a single phase motor hooked up 220 with only three leads.
L1-T1, 2,3,5 tied internally; L2-T4,T8 = clockwise.
L1-T1,T8; L4-T4 = anticlockwise.
L1-T1, 2,3,5 tied internally; L2-T4,T8 = clockwise.
L1-T1,T8; L4-T4 = anticlockwise.
ptonsparky
Tom
- Occupation
- EC - retired
Counterclockwise as well.
- Occupation
- Licensed Electrician
Have you been following me around?
kwired
Electron manager
- Location
- NE Nebraska
but the motors we are talking about do not make all the leads you mention user accessible. The only purpose for T2 and T3 is for dual voltage and this 240 volt only motor likely doesn't even have any midpoint taps of any kind, so that leaves us with Main, Aux, and common leads only. Single phase hermatic refrigeration compressors are typically the same way, only three leads are brought out for user to connect to.
kwired and hillbilly1:
Happy News!
I obtained fresh information about the reversibility of three leads motor from Audel 'Electric motors'. By changing the capacitor connection from start winding to run winding, the rotation of the motor can be reversed.
Note:My original intention was to suggest to the OP to release the impeller of his pump from the sand logged condition by trying to reverse run it after which the motor may be made to run in the normal direction. But the OP had already abandoned the pump!
Happy News!
I obtained fresh information about the reversibility of three leads motor from Audel 'Electric motors'. By changing the capacitor connection from start winding to run winding, the rotation of the motor can be reversed.
Note:My original intention was to suggest to the OP to release the impeller of his pump from the sand logged condition by trying to reverse run it after which the motor may be made to run in the normal direction. But the OP had already abandoned the pump!
kwired
Electron manager
- Location
- NE Nebraska
I think I have seen some motors where you can do that, seems the ones I have seen are PSC motors, and not capacitor start motors. I am pretty sure you can not do that with all motors of this type.
Perhaps you base your conclusion on the short time rating of the starting capacitor. I think no harm would be done to the starting capacitor or to motor winding for a very brief reverse running of the motor for removing the sand logged condition.
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- Occupation
- Licensed Electrician
Let's try this again. Single phase, 240V only motor. L1 has one lead to the motor under the wire nut. L2 has two leads to the motor under the other wire nut. Move the lead that goes to the starting winding from L2 to L1 and the motor will reverse.
The motor will not then even start, for the start winding is shorted out by the common lead at L1.
kwired
Electron manager
- Location
- NE Nebraska
That works because the start winding is a 120 volt coil and the unavailable lead is connected to a center tap of the run winding internally.
The well pump motor could possibly be done this way also. You really need to know the internal wiring schematic, before you determine if it can be reversed. If you just swap leads to effectively move the capacitor to the run lead and the start winding is indeed connected to midpoint of the run winding on one end, you should get reverse rotation, but you will also have coils and capacitor that were not designed for that arrangement.
In order for the simple moving the capacitor to the other winding to work, both windings need to have the same impedance if they are going to have to run either direction with same load, the capacitor being the one thing different between them that causes the necessary phase shift to cause rotation.
Sounds to me like this would be more ideal for a PSC motor than for a capacitor start motor.
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