Check your power line connections

[rustystud]

OK, here's the story. About three weeks ago the power went out. No problem, I went and started up the MEP-002A which is hardwired into the breaker box through a mechanical switch-over box. Generator is running great. Go and throw the main switch to generator power and lights come on.
Now the fun begins. As I started going back to the house the lights went out. What the !&*!!&* !!!!! I check the generator which is still running great but it is showing no power out. Shut-off the generator and start checking things. Everything looks fine. Start it up again, and power is back on. Then after a few minutes the power shuts-off. Again I shut-off the unit and start checking things. This happens four more times before I call it quits and shut off the unit.
Later on that week I go and attack the unit and try and find what is wrong. Everything checks out ! So it must be the A/C regulator. I bought a nice unit from
"Triple Jim" last year, so I Emailed him what was happening. He told me to send the regulator to him and he would check it out. He found nothing wrong ! Graciously he didn't charge me for testing the unit and shipped it back right-away.
So fast forward to today. I have been so busy with other projects around the house that I haven't touched the generator, but we will be having a heat wave hit us this Wednesday with temps in the 100's . So the wife said I better get that generator running now. If she had to endure temperatures in the 100's without A/C there would be "**** to Pay" !!! After all didn't I say when I bought this generator that it would power the whole house ?
So I'm out there today really going after this thing, and what do I finally find ?
A loose connection at the main power connection. The brass "slide" that the nut tightens against the cable with was broken (see pictures). This allowed the cable to shake loose breaking contact with the post.
I swap out a nut and slide from another unit I have and presto the power is back on !
The whole moral of this story is to be sure you check your connections on a regular basis. These MEP units shake pretty good and all that shaking broke that slide.

 

[Poccur]

That is a good find. If you have a wire 'making and breaking' with a load on the gen you can actually start to create heat at that point. The heat then spreads down the wire and makes the copper brittle which breaks more strands as the engine vibrates. The wire can get hot enough to melt thru insulation and then you have potential for fire...It does not look like it got too hot in the pictures so I am glad you found it now...

 

[DieselAddict]

+1.. Good find. That was a fire waiting for an excuse to start.

 

[rustystud]

+1.. Good find. That was a fire waiting for an excuse to start.

You think since you permanently installed the unit that the last thing you need to worry about is the wiring connection.

 

[DieselAddict]

A good lesson for not taking something for granted.

 

[dangier]

Ditto:
I have also found the connections hot from doing full load testing on #4 aluminum cabling.

 

[Guyfang]

Rusty, Rusty, Rusty.

I know you have heard of PMCS. The army worked hard over the last 50 years to develope PMCS. Preventive Maintenance, Checks and Services. And for a good reason. They wanted to develop the habit of checking Before, During and After operation of equipment.

No, checking the load terminals is NOT in the PMCS. BUT, PMCS requires you to walk around the set, checking things. Load terminals are notorious for vibrating loose. Way too many people think that starting the gen set up, loading it down, and turning it off is "Checkin it out". Wrong O.

As a bare minimum, the PMCS should be followed, along with opening the control panel door and the AC output door. Take a gander inside. Sometimes I was VERY surprised at what I found. Sometimes things crawled, jumped, flew or oozed out of the control panel, or other places on a gen set. Looking behind the AC output door is a must. The problem with the output load terminals is that they are made of soft material. You overtighten them and you will be looking for new ones. Under tighten them, and they vibrate loose often.

You might want to think about some different type of ends for the cable pigtails. Round is better. DieselAddict or someone else can give you good advice on that. German stuff might cost you too much!!!!!!!!!!!!!

Something we used to do, was collect up old two prong slave cables. Then remove the cable head. De solder the pins, and then re solder and crimp them on my pigtails. Why re solder and crimp? Well, like the problem you had. Loose terminals. Loose connections cause heat. Heat can melt solder, when it gets bad enough. Look at the ring connectors on a starter cable. Most are soldered and crimped. And that's why.

 

[jimbo913]

I have just three words after seeing that, especially with all the testing you did to locate the problem "check chassis grounds"

 

[rustystud]

Rusty, Rusty, Rusty.

I know you have heard of PMCS. The army worked hard over the last 50 years to develope PMCS. Preventive Maintenance, Checks and Services. And for a good reason. They wanted to develop the habit of checking Before, During and After operation of equipment.

No, checking the load terminals is NOT in the PMCS. BUT, PMCS requires you to walk around the set, checking things. Load terminals are notorious for vibrating loose. Way too many people think that starting the gen set up, loading it down, and turning it off is "Checkin it out". Wrong O.

As a bare minimum, the PMCS should be followed, along with opening the control panel door and the AC output door. Take a gander inside. Sometimes I was VERY surprised at what I found. Sometimes things crawled, jumped, flew or oozed out of the control panel, or other places on a gen set. Looking behind the AC output door is a must. The problem with the output load terminals is that they are made of soft material. You overtighten them and you will be looking for new ones. Under tighten them, and they vibrate loose often.

You might want to think about some different type of ends for the cable pigtails. Round is better. DieselAddict or someone else can give you good advice on that. German stuff might cost you too much!!!!!!!!!!!!!

Something we used to do, was collect up old two prong slave cables. Then remove the cable head. De solder the pins, and then re solder and crimp them on my pigtails. Why re solder and crimp? Well, like the problem you had. Loose terminals. Loose connections cause heat. Heat can melt solder, when it gets bad enough. Look at the ring connectors on a starter cable. Most are soldered and crimped. And that's why.

OK Guy, are you going to be busting my "brass nuts" now ! I purposely use solid copper cable with conductive grease on them. No connections to "come loose" or "unsolder" on me. This is how those brass nuts where meant to be used. I have been playing around with stuff in the power box. Taking it out and removing and adding stuff. So the last time I did it I must not have torqued the nuts done properly.
Oh by the way, I use 1-0 cable for my wiring to the house. No little wires for me.

 

[Guyfang]

Not busting your nuts Greg. Using your situation to make a point to folks. To many folks think starting the gen set once a month is good enough. This kind of thing comes naturally to me, because I had inspectors checking me out 24/7. If we failed an inspection, we spent ANOTHER 24 hours on the rocket site. Fail the re inspection, stay 48 hours longer. And all it took was one lose ground. We had miles of ground strap, hundreds of ground points and ground studs. So if I poke a little fun at you, it's ment well.

 

[rustystud]

There is no way to install any connectors on my wires. In fact I have to squish them together (elongate them) to make them fit in the slots. This has worked well for almost a decade now.
Of course you still must check them on a regular basis. Something which I fell down on doing.

 

[Guyfang]

Ok, ok. You have Mea Culpa enough!!

Remind me to tell the tale of how I flash burned my hands removing a cable under load.