Poof, I saw the Genie

Thank you everyone for responding, Mark that is the exact capacitor that expired(blew the top off), and thank you for the link. I did not have the saw running at the time, but it was connected. I have quick pushed the button before, and only got half speed on the RPC, so that is why the 1 one count, I just start saying thousand, and let go. The green button is not directly connected to the capacitor from what I see, but your asking the wrong person to look at it :)

Thank you for the link for the voltage display.
 
No, I bought it from a member here, and had it shipped. It has been working perfectly until I did something.
 
The short response is that I believe this is a one time event and not related to moving to a higher amp circuit. One thing that hasn't been considered is why the start capacitor was even in the circuit if the RPC was still spinning. There are two common ways to bring the start capacitor into the circuit and then cut it out. One is with a potential relay; that senses the inflow current and connects the start cap until the current drops when the rpc is up to speed. The other way is with a timer, which I believe is usually set to a second or less. A third but less common and crude way is with the start button being the thing that directly connects the start capacitor to the circuit. That third way has the potential to exceed the time capacity of the start cap if you hold the start button in too long. We'd need to know the mechanism for connecting the start capacitor into the circuit to answer why this happened. When you talked about pressing a button I had thought you had a magnetic starter. If you've got a setup where you flip a switch to power up the RPC and then press a start button, it suggests that you have the third way. It's workable, but you run the risk of blowing start caps if you hold the button in too long. If a RPC is spinning and you give it power, it will come up to speed on its own without the need for a start cap, although it may take awhile if the initial rpms aren't very high. That latter may be of use to you if this is the only way to power your 3 Ph equipment. Put a pull rope on the RPC, give it a brisk spin and then turn on the power. It will run without the start cap.
 
I had started the RPC, then shut it down thinking I was going to take awhile to do something, and figured out I was okay and wanted to restart the RPC while it was still spinning down only briefly after shut down. That is when it popped.
 
Aukai said:
I had started the RPC, then shut it down thinking I was going to take awhile to do something, and figured out I was okay and wanted to restart the RPC while it was still spinning down only briefly after shut down. That is when it popped.
Click to expand...
Is the button you mentioned earlier going to a magnetic starter switch? [typically a separate box about 10 x 10 x 4" and you hear a click / snap when you push the start button. [Sorry if the question seems overly elementary, but there is a wide range of experience at the forum] Are you turning a switch to power on the RPC and then pushing that button, or does pushing the button get the RPC powered up? This may also be a situation where some photos of the RPC in question and the insides with the blown capacitor might help to answer the why question.
 
This is what is in the back of the cabinet. The blue wire has an H(hot?) going to one side of the capacitor, and the black wire from the capacitor going to a common ground(?).

 
In the upper photo the connections look like they're going to a potential relay. Holding the start button for any particular length of time shouldn't have any effect on the working of the relay. My guess is that it was just the time for the relay capacitor to go. A lot of us have shop made RPC's with potential relays controlling the capacitor. At some point over the 10+ years since I built mine I must have hit the start button again after initially shutting it off and I haven't experienced a blown capacitor. I haven't googled for it, but I suspect that if there's current feedback from a slowing RPC that's restarted that kills start capacitors, there will be other reports of similar occurrences.
 
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Thank you.
 
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