• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

Motor wiring

Share this page

SilentUnicorn

SilentUnicorn

Yoda
Country flag
Offline
All,
seems like homeowner night at the pub. My question is about single phase capacitor start 220v .75hp motor. More specifically reversing rotation of this motor. This motor is for my South Bend 9 lathe. I have sorted out, and wired, the motor for 220v. I know which wires are the start windings. I also know that in order to reverse rotation I need to reverse these two wires that power the start winding. In the motor are three connections, Leg1, leg2 and a common terminal that i have configured as the center point of the two run windings(for 220v). The start windings have one end wired to the common (the middle connection of the run windings) and the other to leg1. The big question is if i switch the end of the start winding from leg1 to leg2 ...Will the motor reverse??

clear?

m
 
I doubt it, as leg 1 and leg 2 are 120 volts each, using the common wire as the second wire in a 120 volt circuit. Combining leg 1 and leg 2 along with the common wire gives you 240 volts. You can switch leg 1 and 2 and nothing changes in a 240 circuit. Now were talking single phase of course. 3 phase, which is usually, but not always 480 volts and very common in industrial applications, is another story.
 
That is what i thought. In order to reverse this single phase motor i actually need to reverse the start windings. i was hoping that i would only have to swap one wire instead of two. I think i need a different switch.

reference this document
https://www.metalwebnews.com/howto/elec-mtr/elec-mtr.html

m
 
Th' switch is the secret! It needs to swap both legs.
 
All you should need to do is switch the starter winding leads.
 
Thanks- i got that muchlooks like i need to run 6 wires out of the motor to the switch. 2 for L1 and L2, two from the start windings, and two start winding return from the switch to the motor. Sound right?

Do you know anything about different reverse switches? THIS is the one i have. It is a double "L" configuration and i am not sure it sill do what i need it to do.

m
 
Back
Top