How I fixed my Dynamo pump: hums, won't start, no start capacitor

[easttn]

I have an old Pentair Dynamo 1HP that won't start on its own.
http://www.poolsupplyworld.com/Pent...ool-Pump-with-3-Standard-Cord-115V/340197.htm
http://www.pentairpool.com/partslists/pumps-aboveground-dynamo-pump-54.htm
Cant find an internal schematic on the motor.

The back plastic is busted off and the switch is missing with the yellow and blue wire wired together (bypassing switch, I done that). I can plug it up and it hums but wont spin until I give it a spin with my hand. I dont know if the capacitor is missing or there just wasnt one but Im sure if I could wire one in that would fix the problem. The only loose wires goes to the on/off switch so I guess there wasnt a capacitor. There is some kind of centrifugal switch inside because when it gets to spinning, I hear it click. I cant see it in there but I dont know what its for. There is some kind of thermal protection built in but I dont want to take it apart unless I have to.

How can I wire a capacitor to it or can I? There are 2 sides to the capacitor, just not exactly sure where they need to be hooked up. I have an extra one on hand.

 

[easttn]

Re: Pentair Dynamo Wont Start On Its On

I decided to take the pump apart and see if I could figure out the inner workings and the problem. This pump doesnt have a startup capacitor. The smaller pumps must not have them. The pump has a run winding and a startup winding. The startup winding is what starts the pump. Once the pump gets to speed there is a centrifugal switch that works a set of points and disengages the startup winding and then the pump runs on the run winding. The points are under the white plastic plate that has all the wire connections. In my case the points run across terminals 4 and 5 in case anyone wants to check them with a multimeter. There is a round black plastic piece on the shaft that the points lever rides on. Take a screwdriver or something and press down on it to activate the centrifugal switch and break connection with the points.

The points were not making good contact or had some corrosion. I finely sanded both points and adjusted them a little to make better contact. Took an airhose and blew out all the crud. Reassembled and the pump runs like a new one. Anyone having problems with their pump should check either the startup capacitor or the points, whichever may be the case. There is no reason to buy a new pump unless the windings short out.