I am working on an old gas pump that has a Leland 1/3 HP - 1725 rpm 120/240V single phase motor. The tag says division of AMF so my research says this motor was made in the 1950s before Leyland was sold to Howell. I believe it to have bad start caps as it will run when turned by hand but won't start. My question is about the design of the stationary switch. There does not seem to be any visible mechanism to open the contacts after the centrifugal mechanism opens. It has this dual lever setup and when pressed down does not come back by itself. It doesn't appear that the geometry is off as it doesn't seem possible for it to be changed so that it will open the contact by itself. The only thing I can think of is that the magnetism from fields acts on the steel fork lever to reopen the contact. Anyone that can shed light on this for me would be a big help. Since the motor is completely sealed due to being on a gas pump, I cannot simply look while the motor is together. I added a pic to hopefully make this clearer. Also, the motor had a few ounces of fluid inside the housing. Would this have leaked from the caps when they went bad or was it put there on purpose for fire retardant purposes? Thanks

 

The other part of the centrifugal switch will be on the shaft. I will consist of some weights and springs. When the motor is near its opperating speed the weights fly out due to the centrifugal force and will be linked to a sleeve that slides on the shaft. This sleeve will then push against the fixed part of the switch causing the contacts to open.

Les.

 

Thanks for the reply. I reread my original post and I can see where I wasn't clear on what I was asking. The specific thing I am asking about is there doesn't seem to be anything to make the contacts open after they are closed. The centrifugal mechanism looks fine. If I press on the fork it will close the contact. When I let go, they remained closed. I bent the tangs on the spring and the lever with the contact on it slightly and it doesn't seem to be anyway for it get it to come back by itself. If I bend them so they will stay open the contacts will not close at all when I push on the fork. It doesn't appear like there is anything missing and the spring seems strong for its size. The only way I can see the contacts opening after the centrifugal mechanism releases is if the magnetism from the field pulls on the fork to open them. The fork does stick to a magnet. I hope that is clearer. Thanks again.

 

Looks to me as though the spring is intended to pull the fork up (to open the contact), but perhaps there is excessive friction between the fork ends and the guide posts, preventing that happening.

 

After staring at and messing with this thing for over an hour I finally figured it out. Somehow the front pivot point for the small lever was standing up too straight and since the geometry was wrong would not return the contact to the open position by itself. Either I somehow bumped it with the rotor when I took it apart or being under tension for 60 years or so bent it by creep. Funny thing is it was near perfectly vertical so didn't look bent. It was not easy to bend either. Anyway put in two new start caps, put it together and it works great. Pumped about 50 gallons tonight. In the almost 40 years I've had it it's pumped 200-300 gallons of fuel a week, every week with the only problems caused by mice building nests in it. Hopefully it will last another 40. Thanks again for the replies.