chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
This is the start cap bank in a Ronk phase converter. I have had three start cap failures in the last two years with this thing but never like this.
Crazy cap failure
- Thread starter chris kennedy
- Start date
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mgookin
Senior Member
- Location
- Fort Myers, FL
Well it's easy to tell which one went bad!
That is interesting.
That is interesting.
big john
Senior Member
- Location
- Portland, ME
Is it the one in the back, on the right? :angel:
Chris, if you're getting repeated start cap failures it sounds like you may have a sticky centrifugal switch or else this thing just isn't getting up to speed for some reason. Is it starting under load and bogging way down?
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sparkyrick
Senior Member
- Location
- Appleton, Wi
That went kablooey!
- Occupation
- Licensed Electrician
They sometimes go quietly sometimes they go with dramatic flair like the one in the picture.
I agree with big john. Something is keeping them in the circuit too long.
I agree with big john. Something is keeping them in the circuit too long.
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
The start contactor is failing mechanically, meaning jammed closed, no voltage across coil. If your familiar with these, both the run bank and the start bank come with an extra cap not in the circuit. After I lost the first contactor and caps, when I fired the thing back up the start contactor would close, open, close and open again in about 2 seconds. I put the other start cap in the circuit and all was well for about 8 months.
Important to note here that Ronk has outstanding tech support and after the first cap/contactor failure, a lengthy call between them and myself it was determined the unit was functioning properly.
I have installed 4 or 5 of these things and never had a call back on the others.
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
Here is the contactor, you can see the little button in the middle is jammed in.
sparkyrick
Senior Member
- Location
- Appleton, Wi
Here is the contactor, you can see the little button in the middle is jammed in.
Are the contacts welding shut?
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
I don't believe so, the first one I replaced I was able to get the tip of my knife in there and fiddle with it until it popped back out. Was unable to autopsy it, warranty return. Have yet to take the one in question now out.
kwired
Electron manager
- Location
- NE Nebraska
That extra capacitor is not a spare for when one fails, it is for the purpose of fine tuning the converter to your actual load. You often will find they will work as is shipped, but you may find they work even better if you make the fine tuning adjustments. You can get more or less phase shift for the derived phase by increasing or reducing the amount of capacitance in the circuit. You can also get more variety of capacitance values out of what is installed just by different combinations of series or parallel connections between what capacitors are provided.
You possibly need to connect more capacitor to the starting circuit in your application - apparently it is taxing what is connected a little too much.
I haven't seen one explode like that on a phase converter - yet, but have seen same thing happen on single phase motors when centrifugal switch or potential relay is leaving the capacitor in the circuit for too long. Oil filled capacitors don't normally do that because they have a fuse link that separates when the case begins to bulge from too much internal pressure, but the oil filled are usually the lower value run capacitors and the higher values are needed for starting.
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