wheres the voltage

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billdozier

Senior Member
Location
gulf coast
Hey guys trying to understand why on a 220 motor I can see the voltage across leads on input. But cant see the voltage on load side terminals. What I had today was a flow switch for a well pump. My boss said I would never see the voltage across load side. Why not? We read 110 to ground on all 4 screws. And 220 on input but nothing on output. We had amperage on load side wires so thier was current just couldnt read the voltage. Thanks for input
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
If you are talking about a pressure switch then you should be reading 240v on the load side of the switch otherwise how could the pump run. Is this what you are saying?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Hey guys trying to understand why on a 220 motor I can see the voltage across leads on input. But cant see the voltage on load side terminals. What I had today was a flow switch for a well pump. My boss said I would never see the voltage across load side. Why not? We read 110 to ground on all 4 screws. And 220 on input but nothing on output. We had amperage on load side wires so thier was current just couldnt read the voltage. Thanks for input
Sounds like one side of the switch is not making contact, which is why you're reading the 120v on the fourth terminal through the motor, and nothing across the motor.

To confirm this, measure across each contact, between L1 line and L1 load, and then between L2 line and L2 load. If I'm right, you'll read 240v across the bad contact.

Of course, if the motor is running during all this, then there's something wrong with the tester or how its test leads are being held. In that case, please disregard this post.
 

billdozier

Senior Member
Location
gulf coast
I agree with both these posts/ My pm was trying to tell me you would never read it. I called him on it but wanted to make sure I was correct thanks
 
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