- Joined
- Nov 27, 2012
- Messages
- 7,854
I agree with Mark, might as well replace both while you're at it. I read that the start caps are usually the ones to go out first. Cheap ones don't have good duty cycle so if you are doing a job where you have to turn & off the machine repeatedly you eventually blow the start cap.
Sure enough, that's what happened to my mill some years ago. Start cap blew during a production run I was doing. My lathe has the same motor as my mill & it's older but surprisingly it hasn't blew a cap yet. If you have a multimeter (even better if it can measure capacitance) you can check if the cap is bad. Sometimes the caps will also show physical signs of failure, like bulging or cracks, depending on the type of cap.
I don't know much about AC motors so I wasn't sure about ordering caps from Mcmaster at the time since they listed a uF range. Don't see that in DC & is what I'm used to. I ended up finding the exact values & physical size at Grainger. Weren't too expensive & I was able to just drive down to pick them up the next morning.
They were their house Dayton brand & at first I was worried cause they were made in China. But they looked nice & had metal cases. As mentioned, I had to cut the wires on the old ones & I installed spade connectors as that's what the new caps had. That will make future changes quick & easy.
Weird thing is the stock start cap was made in China & the stock run cap was German, both with plastic cases. I replaced both & haven't had a problem since.
Sure enough, that's what happened to my mill some years ago. Start cap blew during a production run I was doing. My lathe has the same motor as my mill & it's older but surprisingly it hasn't blew a cap yet. If you have a multimeter (even better if it can measure capacitance) you can check if the cap is bad. Sometimes the caps will also show physical signs of failure, like bulging or cracks, depending on the type of cap.
I don't know much about AC motors so I wasn't sure about ordering caps from Mcmaster at the time since they listed a uF range. Don't see that in DC & is what I'm used to. I ended up finding the exact values & physical size at Grainger. Weren't too expensive & I was able to just drive down to pick them up the next morning.
They were their house Dayton brand & at first I was worried cause they were made in China. But they looked nice & had metal cases. As mentioned, I had to cut the wires on the old ones & I installed spade connectors as that's what the new caps had. That will make future changes quick & easy.
Weird thing is the stock start cap was made in China & the stock run cap was German, both with plastic cases. I replaced both & haven't had a problem since.