Changing from 110 to 220...

[mrcaptainbob]

Have a new shalow well pump. Existing is 110V. It has a switch available for changing to 220. There are two poles (and two wires) existing, one black, one white. THe black has a tag says it's set for 110. I'm running 14/2wg for the 220 and plan to red tape the white at both ends. I understand why water heaters don;t need the neautral, but why would a motor not need it when running 220? If it's needed for 110, why not for 220? The book does not explain anything other than to move the switch and shows the connections on pressure switch. Have not looked 'closely' at the physical pump wiring, there may be a capped of third wire. What should I expect when I do check it out?

[Glasshousebltr]

14/2 doesn't sound right, better check with the manufacturer. In fact 14/2 has been outlawed for even lighting, in some counties around here.

Bob

[HayZee518]

A motor that's rated 120/240 has two windings set in parallel for 120 volt operation. When you switch to 240 the switch puts the windings in series with each other so that the two 120 volt windings are additive. When voltage goes up - amperage goes down by one half. So let's say your motor was rated 18 amps at 120, running it on 240 will half the amperage to 9 amps. Also running it at a higher voltage increases the efficiency.

[mrcaptainbob]

Okay, I'll proceed with confidance! Thanks for the help, guy's!