Did you just get back from the service call This late or was you on a date
Emergency service call - ended well on two fronts!
Got a call from the fish plant earlier this evening. All of their compressors at one of their facilities shut off and they couldn't turn them back on. They make a buttload of ice there and it's probably the most crucial part of the operation. In addition to the ice, all of their refrigeration for plate freezers, drive-in freezers, etc. are dependent on the compressor system.
So I hopped in the van and headed down there. There are three main anhydrous ammonia compressors, about 200 hp each, plus 3 booster pumps, about 150 hp each (or so). NOTHING was running. Keep in mind this place was built a long-ass time ago, probably when god was still a kid, and has suffered through who knows how many maintenance crews ever since.
The guy said that he started up compressors 2 and 3 just fine, but when he switched on compressor #1, that's when everything shut down. I went over to the breaker panel and found the 120 volt control breaker tripped. Shut all the control switches to Off, then reset the breaker. Fired up compressors 2 and 3, and the boosters, so they could at least maintain SOME refrigeration while I figured out what was wrong. He said that it happened right when he switched #1 compressor to Auto on the HOA. So I started there. Ohmed out the wire on that terminal, found it was faulted to ground. Did some ol' fashioned troubleshooting from there. This particular wire left the control panel and ran out to the compressor's pressure and temperature cutouts. Chased the fault through all the devices and finally narrowed it down to the switch leg returning the cutout loop to the relay for comp #1 starter.
Wire was in 1/2" EMT, hard piped all the way to the cutout mounting thing. No flex or anything. Pulled it out and ran a new wire, reterminated, ohmed it out again (fault was gone) and fired it up. Worked. Then I went and took the old wire outside to examine it. Found the insulation rubbed through. Wasn't at a bend or a conduit entry or anything - it was right in the middle of a straight run of pipe. Weird. Anyway, if this isn't evidence enough that running flex to vibrating parts like big compressors is a good idea, then I don't know what is.
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The other good news is that QC girl asked me for my phone number :thumbup: That means I'm going to have to pester her to start sexting me.
So I hopped in the van and headed down there. There are three main anhydrous ammonia compressors, about 200 hp each, plus 3 booster pumps, about 150 hp each (or so). NOTHING was running. Keep in mind this place was built a long-ass time ago, probably when god was still a kid, and has suffered through who knows how many maintenance crews ever since.
The guy said that he started up compressors 2 and 3 just fine, but when he switched on compressor #1, that's when everything shut down. I went over to the breaker panel and found the 120 volt control breaker tripped. Shut all the control switches to Off, then reset the breaker. Fired up compressors 2 and 3, and the boosters, so they could at least maintain SOME refrigeration while I figured out what was wrong. He said that it happened right when he switched #1 compressor to Auto on the HOA. So I started there. Ohmed out the wire on that terminal, found it was faulted to ground. Did some ol' fashioned troubleshooting from there. This particular wire left the control panel and ran out to the compressor's pressure and temperature cutouts. Chased the fault through all the devices and finally narrowed it down to the switch leg returning the cutout loop to the relay for comp #1 starter.
Wire was in 1/2" EMT, hard piped all the way to the cutout mounting thing. No flex or anything. Pulled it out and ran a new wire, reterminated, ohmed it out again (fault was gone) and fired it up. Worked. Then I went and took the old wire outside to examine it. Found the insulation rubbed through. Wasn't at a bend or a conduit entry or anything - it was right in the middle of a straight run of pipe. Weird. Anyway, if this isn't evidence enough that running flex to vibrating parts like big compressors is a good idea, then I don't know what is.
The other good news is that QC girl asked me for my phone number :thumbup: That means I'm going to have to pester her to start sexting me.
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If you're still ohmming, you need to get a megger!!
This is one I found with the same problem. It had control power until you pressed start. Crappy old pump panel, that butt splice with the burn mark was face down. It looked fine until I picked it up and turned it over. Megger picked it right up.
This is one I found with the same problem. It had control power until you pressed start. Crappy old pump panel, that butt splice with the burn mark was face down. It looked fine until I picked it up and turned it over. Megger picked it right up.
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