Meo 006a Meltdown !!!

[gscales123]

Hey Had a meltdown on my mep 006a. I started it the other day and run it about 10 minutes under load while setting my bandsaw mill. 40 hp mill motor and mep run perfect. Turned them off then smelled wiring burning, found my alternator smoking bad inside of it. I unhooked the wiring from alternator and ordered a new one. something come up and i needed the mill so i started it [alternator still there just unplugged] and when the 416 volts come up it blew sparks all over me. I turned it off with a long stick. Kinda spooked. A lot spooked! Opened the gauge panel and found the wires burnt off of the phase volts switch and some others had been hot. Top connection going out to special relay box was hot. Wiring coming out of special relay to engine was also hot. The ground in the special relay box also had at least one wire that got hot on it. I checked the wiring on the ground lug going out of the machine and my ground rod and all that was good. Did I do this by running without the alternator? This is a badly needed machine right now - any help would be greatly appreciated!

 

[DieselAddict]

Some photos would help.

The alternator being out of the circuit is not going to directly cause what you are describing. Its too early to jump to conclusions. Lets see as many photos as you can supply and start figuring out what happened.

 

[gscales123]

Ok Thanks Will go take some pics

 

[Guyfang]

Take a lot of pictures. And go over to the AC side, left rear door. Need to see if and how much damage is there. Get some close ups of the CB1 and all the other output wires. Load terminals front and back. Wire harnesses between the Special Relay box. Control cube and the wire harnes that is in it. I have seen something like this twice, and had it happen to me once.

Yep, it's time to see if the underware need to be changed when it happens. This sounds like a main gen shorted out. Your ground may have not been good also. It sounds like you had voltage going to ground, but the ground had no way to direct it. Pay good attention to the front and back sides of the load terminals. Maybe one of your wires came loose and shorted out between another phase and ground.

When you are done taking pictures, pull the Special relay box and open it. Take pictures of/inspect the tap interchange board, (reconnection board to you) and both sides. If your lucky, it might just be there, insted of the main gen. But in any case, this will not be a fast fix.

 

[Light in the Dark]

Check your batteries and the hold downs. I have experienced a meltdown on a smaller set, due to the positive terminal(s) making contact on a tie down J bracket. Caused the whole machine to go +. Burned up most everything, and definitely spooky! The emergency shutdown was rendered null during it too, so I had to undo the positive side of the battery while the machine was racing and brown smoke billout out of it. Yeah....

 

[gscales123]

 

[Guyfang]

Ok, doesn't look as bad as I thought. At first, I thought it was not AC related. But it is somewhat. The wires burnt off the S6 in the control panel are AC wires.

Next thought. In picture 5, it looks like this is not the first time the ground wire burnt up. In picture 5&9, it looks like the J1/P1 wire harnes are rubbing on the S/P relay box side. Common problem.

Was the S/P relay box bolted on to the relay table? Or just laying in there? You need to find out where the root cause is.

In picture 1, the cover of the Thermal Watt Converter was off. Was it always so? Or did you just take it off? This is one place, (in seem to remember) were we can get AC and DC in the same place, in the control cube. can you see any other places where the wire harnes is toasted?

one of the big problem areas of the gen set was people not securing the wire harnesses. I can see several in your pictures where wires harnesses are rubbing on metal. There is AC and DC in the SP relay box, so this is an area were this sort of problem can happen.

 

[gscales123]

Both panels was bolted on I took them off to inspect. I will look more at the harness see what i can find. This is the first time i noticed the spliced wire in pic 5 Thanks

 

[gscales123]

Went over all the wiring cannot find any bare wires other than in the pics from the meltdown, not sure if the whole problem was in the phase watts switch it is frozen in place. Not sure if i should try to fix, it has been nightmare sense i bought it. Diesel going in oil, fixed that twice, removed spring and ball out of return line, oil cooler pouring oil out, float switch in charge tank replaced, fuel pump rebuild. Now this, Has to be a better way to run a 40hp motor than this.

 

[Triple Jim]

...Has to be a better way to run a 40hp motor than this.

The local small sawmill has three bandsaws, each run by gasoline engine. Your saw sounds bigger though.

 

[Guyfang]

You need to decide what you want to do. Remember, some of these sets are older the dirt. None of the problems you mentioned are show stoppers. Easy fixes. Perturbing, yes. But have seen it all, and this isn't bad till now.