3 wires for well pump - all black

Reply

  #1  
Old 05-19-18, 11:33 AM
Q
Member
Thread Starter
Join Date: Jun 2014
Location: Canada
Posts: 1,761
Received 1 Vote on 1 Post
3 wires for well pump - all black

I've got a well pump that had wires cut/disconnected without labelling. The 3 wires are all black. How do I figure out which is which to splice it back to the motor control.
I can't easily do a continuity test since the splice point is 75m away from the motor control.
 
  #2  
Old 05-19-18, 12:41 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 60,854
Received 1,336 Votes on 1,234 Posts
You have to do a continuity check.

Are the connection points labeled at the control ?
They should be something like S (start) R (run) C (common).
This must be done first.

Splice all three wires.
Go to pump control and disconnect the three wires.
Label the three wires A, B, C.
A-B= ohms ?
A-C= ohms ?
B-C= ohms ?

Post what you measure and we can tell you which wire is which.
 
  #3  
Old 05-19-18, 05:39 PM
Q
Member
Thread Starter
Join Date: Jun 2014
Location: Canada
Posts: 1,761
Received 1 Vote on 1 Post
Splice all 3 together at the cut point near the pump?
The wires are twisted the entire 75m length and buried so even if I know what they are at the control, if they're spliced at the other end, then I still need to figure out
A) which of the 3 is which from the source wire
B) which of the 3 is which on the pump
then splice those.
all the wires on the pump are black as well. Not sure which of the 3 to splice to the 3 from the control.

In the image c=control, p=pump


What's the background to the ohm test by the way? If I disconnect all the 3 wires at the control then why will the ohms be different. They're just 3 wires spliced together then?

Edit: I see what you mean. Splice the cut point and then test and the motor will show different resistances?
 

Last edited by qwertyjjj; 05-19-18 at 06:34 PM.
  #4  
Old 05-19-18, 06:55 PM
Q
Member
Thread Starter
Join Date: Jun 2014
Location: Canada
Posts: 1,761
Received 1 Vote on 1 Post
They are labelled black, yellow, and red on the control box.
R start
Y common
B main
 
  #5  
Old 05-19-18, 07:05 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 60,854
Received 1,336 Votes on 1,234 Posts
Splice the cut point and then test and the motor will show different resistances?
Yes...... that is correct.
 
  #6  
Old 05-20-18, 05:26 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 36 Votes on 28 Posts
If you simply want to identify the three leads then after marking the leads on either side of any splice cut them so each lead is free at each end. Connect a battery to two of the three leads, any battery will work. Go to the other end and test pairs with a suitable voltmeter based on the battery voltage until you identify the lead connected to the red probe of the meter as displaying a positive voltage from the battery. The lead connected to the black probe of the meter will be the negative battery connection and the unconnected lead will be the lead unconnected at both ends. Permanently mark the three leads with the same number,number, letter or symbol at each end, i.e. mark the lead connected to battery plus with a 1 or A or + and the lead connected to the meter red probe with the same number, letter or symbol. Do the same for the second lead using a 2 or B or - and then the third lead use 3 or C or something on both ends.
 
  #7  
Old 05-20-18, 07:30 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 60,854
Received 1,336 Votes on 1,234 Posts
The three wires got cut midway between the submersible pump and the controller
and they are all black.
 
  #8  
Old 05-20-18, 07:35 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 36 Votes on 28 Posts
Then do the resistance test from the cut point to the pump and the battery test from the cut point to the controller.
 
  #9  
Old 06-09-18, 06:10 PM
Q
Member
Thread Starter
Join Date: Jun 2014
Location: Canada
Posts: 1,761
Received 1 Vote on 1 Post
I spliced them and am trying the resistance trea at the control box
My ohmmeter just jumps all over the place so I can't get a consistent reading between any of the 3 wires
. It's measuring AC voltage correctly so seems to be working unless the ohm setting needs a fresh battery.
Is there anyway to trial and error the wires or will it burn the motor?
 
  #10  
Old 06-09-18, 06:31 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 60,854
Received 1,336 Votes on 1,234 Posts
Go to the lowest ohm scale. Usually Rx1. Make sure the meter zeroes out when you touch the leads together. If not.... change the battery.

You cannot guess by randomly connecting voltage without possible motor damage.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: