Motor hesitates and then starts

I have a year and half old Hayward motor that has recently developed some issues. One day I noticed the pump had not started and the breaker was thrown. I attempted to start the pump manually and the pump hesitated for 4-5 seconds and then started like nothing was wrong. The next day it started automatically but the following day I again found the breaker thrown. Restarting it resulted in the same 4-5 second humming but this time it blew the circuit breaker. I flipped the switch back on and it hesitated again and then turned on and subsequently functioned without an issue. With the electricity off I manually turned the impeller and it rotated without any resistance. I have also removed the capacitor and tested it with a multimeter and it seems to be good. Anyone have any thoughts on what would cause this hesitation in the motor?

Hi!

This is one for Al (Poconos). If I tried to answer, it would just be 'parroting' what I've learned from reading his posts and I'd probably get the terminology wrong.

If Al doesn't see this and respond, I'll dive in and give it my best. :)

I'll shoot him an email and see if he'll check into this thread...

Couple of questions first. I'm pretty sure the breaker you refer to is in your power panel. What is the current rating and is the motor 120 or 240 and what is the current draw on the motors info plate? Also, before the breaker tripped and the motor was humming could you tell if the rotor was turning at all? I'm suspecting the centrifugal switch contacts are crummy and you may have an undersized breaker. If the switch contacts are crummy and the starting circuit is open the rotor will not turn. I never looked at the current in this condition so I don't know how that would relate to the normal running current. Would be higher but do not know if it would be enough to trip a breaker. I think the thermal cutout would go first but not sure. Normally when a cap fails it doesn't fix itself.
Al

Thanks for the replies. The current rating on the breaker is 20A and is in the power panel next to the motor. The motor is set at 115V and the plate indicates it draws 15A. When the break trips the motor is either just humming or I hear the shaft slowly spinning almost like it is rotating once ever second and then all of the sudden it kicks in like nothing happened. The breaker is the same that I had on my old motor that I had for 10 years the finally died. I replaced it with this motor and it has the same specs as the old one. I was wondering about the thermal cutoff too. When I start it up I always know if its going to trip the breaker within a few seconds because it will do this if it doesn't start rotating at regular speed within 4-5 seconds. If it goes beyond 5 second and is still humming it shuts off. I've also ordered a new cap (because they're a relatively cheap fix) which will be here this weekend. I'll replace it and see what happens.

A couple of comments. Good idea to try the new cap. To be honest I don't now what the rotation speed, if any, would occur with a shorted cap. I do know that an open in the starting circuit will yield zero rotation. Circuit breakers do sometimes weaken, that is trip at a lower current than the rating. Just an FYI though as the breaker isn't the problem. While you're in the area you may as well clean the switch contacts too. You can use a piece of 600 grit wet-or-dry paper to clean them. Hope the cap is the easy fix.
Al

The new cap seems to have done the trick. Not sure why the multimeter test indicated that the old cap was good or why it seemed to be an intermittent problem. Oh well. Thanks for the help.