MEP-805A T1 Issue

[hepperj27]

Hey everyone new here and this is my first post. So as the title says I acquired an MEP-805A. I got the engine running and it runs well and seems to be at operating speed. I started the engine and let it run and warm up for awhile and noticed both the volt and frequency meters were reading zero. So I held S1 in the start position for a few seconds and notice smoke coming from the output box. I immediately let off and shut the machine down. Looking at the output box I found both wires going to terminal 1 and 2 on the T1 were melted. Checked to see that the wires were hooked to the proper terminals and they seemed to be. So I replaced the wires and continued to try and troubleshoot per the TM but it was difficult because I can't hold S1 in the start position for longer than 1-2 seconds or it burns up the wires. Finally after about a day of trying to troubleshoot I decided to just unhook one of the wires to the T1. When I did that now when I hold up S1 in start it will bring voltage up to about 98VAC on each leg to neutral and around 168VAC across each leg. Moving the voltage adjustment POT does nothing. And frequency was around 60hz but was difficult to adjust. And when I let S1 go back to Run frequency drops to zero and voltage to about 15VAC at the convenience receptical. I am leaning towards the T1 being faulty but would like someone who knows more about them to give their opinion before I throw parts at it.

 

[Mullaney]

Hey everyone new here and this is my first post. So as the title says I acquired an MEP-805A. I got the engine running and it runs well and seems to be at operating speed. I started the engine and let it run and warm up for awhile and noticed both the volt and frequency meters were reading zero. So I held S1 in the start position for a few seconds and notice smoke coming from the output box. I immediately let off and shut the machine down. Looking at the output box I found both wires going to terminal 1 and 2 on the T1 were melted. Checked to see that the wires were hooked to the proper terminals and they seemed to be. So I replaced the wires and continued to try and troubleshoot per the TM but it was difficult because I can't hold S1 in the start position for longer than 1-2 seconds or it burns up the wires. Finally after about a day of trying to troubleshoot I decided to just unhook one of the wires to the T1. When I did that now when I hold up S1 in start it will bring voltage up to about 98VAC on each leg to neutral and around 168VAC across each leg. Moving the voltage adjustment POT does nothing. And frequency was around 60hz but was difficult to adjust. And when I let S1 go back to Run frequency drops to zero and voltage to about 15VAC at the convenience receptical. I am leaning towards the T1 being faulty but would like someone who knows more about them to give their opinion before I throw parts at it.

.
Welcome to the Outfit!

Happy to hear that you bought yourself a Mobile Electrical Power generator. You might want to download the TM's (Technical Manuals). There is some pretty details troubleshooting in them thar books!

Links are below to make it easy to find them in the Technical Manuals section

All the TM's you need to work on the MEP-805B Generator set.

Here are the TM's you need to work on the MEP-805B generator set. Be advised, there are OTHER uploaded files that pertain to the MEP-805B in the TM forum. So LOOK for them.

www.steelsoldiers.com

MEP-806B and MEP-805B Injector Pump Special Tool

Should you ever want to remove the Injector Pump on a MEP-805B or MEP-806B, you need to make this tool, (its an easy job) to properly remove the IP.

www.steelsoldiers.com

There are several folks here who are a lot more skilled in repairing these things than me - but having the books might get you a "running start" on troubleshooting. Again, welcome to the group!

 

[hepperj27]

Thanks for the Reply!

So I've gone through most of the troubleshooting procedures for the generator portion of the set outlined in TM9-6115-644-24 WP0005. The reason I say most is because I can't check the T1 transformer and droop current transformer properly as I don't have a variable power source. Was curious if there is a simpler way to check these with just a multimeter?

 

[hepperj27]

Okay so I just tested the T1 for short to ground (I don't know why I didn't think of that before) and it is definitely bad. Where can I go about finding one of these. Have typed the part number into Google and a few sites show up but I can't find anywhere to buy it. I have the Libby A1, R16, and T1 by the way. I've heard of the TRC regulator kit maybe that should be the direction I should go?

 

[Mullaney]

Okay so I just tested the T1 for short to ground (I don't know why I didn't think of that before) and it is definitely bad. Where can I go about finding one of these. Have typed the part number into Google and a few sites show up but I can't find anywhere to buy it. I have the Libby A1, R16, and T1 by the way. I've heard of the TRC regulator kit maybe that should be the direction I should go?

.
Let me string together a few of the guys and hopefully get you some answers. What you need to know is "above my paygrade".

Help Guys!

@Guyfang
@kloppk
@Tinstar

 

[kloppk]

He's all set.