MEP-004A Under Frequency Indicator Light

[1800 Diesel]

OK for the few of you who work on the water-cooled models, I just did a "1st for me" light-off for this unit & I've got an under-frequency indication but freq meter is reading 60 hz. Tried to reset several times, but no change. Closed the AC breaker and tested voltage & frequency at L1, L2 & L3. All close to 120v and freq at 60 hz. Since it was getting late I didn't want to disturb too many of my fine neighbors so have shut down for the night. One thing I did do was to switch the start/run/stop switch to the start position and when I do that the under freq indicator light goes out.

Forgive me if this is a no-brainer found right in the troubleshooting section of the TM but I needed to get some supper before I dug through the manual. Will be doing that next....thanks for any ideas or comments...BTW, this unit has not been modified (yet) for the single phase re-wire....all components as found except oil & fuel & filters....

Thanks for any help sent,

Kevin

Edit--A quick-look at the schematic shows relay K12 for under freq. Once I locate it on the unit, will swap the relay out with a known good one and retest. Won't be able to run it until this coming Friday though....will report findings.

 

[PeterD]

Two thoughts, one just lurking in the back of my mind is that the under-frequency feature is not active on the 004, only on the precise model. I could be wrong on that however.

The other thought is easier: did you put an external frequency meter (say a Kill-a-watt) and verify the frequency? You can test the frequency meter by connecting the input of the transducer (on the rear wall of the instrument box) to 120 volts ac from any ac outlet.

 

[1800 Diesel]

Two thoughts, one just lurking in the back of my mind is that the under-frequency feature is not active on the 004, only on the precise model. I could be wrong on that however.

The other thought is easier: did you put an external frequency meter (say a Kill-a-watt) and verify the frequency? You can test the frequency meter by connecting the input of the transducer (on the rear wall of the instrument box) to 120 volts ac from any ac outlet.

Peter,

I did test both freq & voltage at L1, L2 & L3 with an Extech MA220--my "good" meter since I can't afford a Fluke. Also don't own a Kill-a-watt meter. And from what I can tell in the TM, the utility sets do monitor freq, but they don't have the 50/60hz switch. Otherwise I would think they wouldn't install the fault indicator light and relay K12, right?

BTW, before I secured the shop last night I closed the DC breaker and energized fault indicator board and only the low oil pressure light came on, no under freq light. Being near midnight I didn't light off the generator, but hopefully whatever gremlin was running around got spooked and departed the pattern. Will do a light-off Friday evening to confirm. Thanks for checkin' in.

Kevin

 

[skidunits4you]

The fault lights and relays are installed on most of the 004, 005 and 006 units but some faults only work on percise units

 

[1800 Diesel]

The fault lights and relays are installed on most of the 004, 005 and 006 units but some faults only work on percise units

Maybe that's why I couldn't locate relay K12, though I didn't spend much looking time being it was so late. Still doesn't seem logical that they would install the wiring, lights & possibly relays "just because"...could be it's cheaper for standardization of components and then they could just add the items needed for the precise models.

 

[flydude92]

I have an 005 but it looks like K12 is in the Governor Control Unit which you wouldn't have. Do you have any sockets that are missing their
'terminator' plugs?

Brian

 

[1800 Diesel]

I have an 005 but it looks like K12 is in the Governor Control Unit which you wouldn't have. Do you have any sockets that are missing their
'terminator' plugs?

Brian

Brian,

Lit off the unit this morning and at first the UF light did not come on. After about 5 minutes of running it will light up. I can hit reset and clear the light for another 5 minutes or so of running & then it will come back on again...I can repeat this over and over with same results. Freq meter does not move when UF light comes on and as verified by external test meter, freq remains constant & steady. A few basic facts about the unit:

No single phase mods. Onboard freq meter right at 60hz and stable. Closed AC breaker (again) & confirmed same freq at L1, L2 & L3 with my meter. Verified 120-120-120 volts at each lug as well & 208 across 2 legs.

When you mention missing sockets can you elaborate what area to look? All my MEP-004As have a couple sockets that are "capped" with no wiring. See 1st photo below showing the inside of this unit.

This morning I noticed some brown stuff that had dripped on the reconnection board. Opened the control cubicle and found the thermal watt converter with the all-too-common leakage. See 2nd photo. Since this component is related to the frequency meter circuit (others are welcome to explain exactly what the TWC does) as per Figure 3-55 on page 3-131 of TM34. Since I have a donor unit on the property, I'll swap this item out, unless someone knows a reason I shouldn't (not sure if both sets are the same make, but they are built from the same drawings so.......hopefully I won't fry anything....

I took a phone video today but it's 500 MB. SS site said file was too large. Basically it showed me going through the standard pre-start, then start-up and showed the freq & AC voltmeter, the illuminated UF light and then me testing the L1, L2 & L3 output lugs all showing ~120V & 60hz. Also tried to reset several times and also reset the DC breaker several times. As reported previously, the UF light goes out when I switch the start/run/stop switch to start while the set is running.

Edit to 1st para above. After running the set off & on for an hour or so, the UF light stayed on & I could not clear it in any manner...Anyone have any more ideas? Hopefully the TWC is causing the problem, but yet nothing abnormal on test meter or onboard meter....still stumped....

Thanks for helping if you can,

Kevin

Afternoon edit: Decided to add some load to the set (7 1/2 KW) and that didn't make any difference. UF light still lit up...
Again hit the start switch while unit was running & UF light goes out. Does that give anyone a clue? Could that switch have a defect causing a circuit to be hot that shouldn't be? Still didn't swap out the thermal watt converter...hoping that'll take care of the issue, but my luck usually doesn't work out that way....

 

[Munchies]

I have picked Triple Jims brain about the TWC. I want to boil or sweat out the potting and figure out whats going on in there, but its such a PITA, I havent bothered yet. I have had to replace 50% of mine. Good luck getting the guys at TRC in florida to awnser any questions though. I have successfully swapped on from a 30kw TQG to a mep-005a without issue even though they are slightly different.

 

[flydude92]

1800 Diesel

The first photo you showed was the box I was thinking about. I was wondering if you were
missing any of those ‘caps’. Mine had some jumper wires installed in them I assume to bypass
some circuit that wasn’t used like the governor control unit. Check all your connectors including those ‘caps’.
A couple of mine had corrosion on the pins. I am looking at diagrams for the 005 and wonder if you have a ‘cap’ on P31?
If so are any pins corroded?

I’ve never seen that leakage before but I doubt it would hurt anything to swap the part.

What happens to the UF light when you turn on the battle short switch?
According to the diagrams that should cause the light to go out temporarily.

I haven’t found a reason in the diagrams for the start switch to cause it to go out but I will check
more when I get a chance.

When I couldn’t find a reason my generator would not shut off when I had an over voltage problem
I started looking for wiring problems. That’s when I found my start-run-stop switch was wired to bypass some safeties. Who knows what someone may have
done to it. Anything is possible.
You can test the switch using the TM’s to verify it works.

Brian

 

[1800 Diesel]

I have picked Triple Jims brain about the TWC. I want to boil or sweat out the potting and figure out whats going on in there, but its such a PITA, I havent bothered yet. I have had to replace 50% of mine. Good luck getting the guys at TRC in florida to awnser any questions though. I have successfully swapped on from a 30kw TQG to a mep-005a without issue even though they are slightly different.

Thanks--since I have a "donor" MEP-004A on hand I'm somewhat confident that the replacement TWC should be a match. Haven't checked the wire connections from one unit to another but expect no differences. Hadn't figured on contacting the Clearwater folks. On the replacement ratio you mentioned, that doesn't surprise me--I did a survey of several MEP4s last week and over half of them had the "oil" leaking out inside and below the control cubicle.

Hopefully on this one (it's for my brother over in Pearl River County) the TWC swap will solve the problem. I can't stop thinking about the fact that the UF light goes out when I hit the start/run/stop switch to the start position (while running). Don't have enough electrical experience to sort out the schematics and all the components connected to the UF indicator light circuit.

Thanks again for the comments

Kevin

 

[Munchies]

I have not really thought about the problem yet, but I saw the leaky goo (stickiest crap I have ever seen. I had to burn it with a torch to get it off sheetmetal) and thought I would drop in. I only called TRC to try and get an engineer on the line who could say if the new and old are functionally the same. I did it anyhow. Works good, no leaky.

 

[1800 Diesel]

1800 Diesel

The first photo you showed was the box I was thinking about. I was wondering if you were
missing any of those ‘caps’. Mine had some jumper wires installed in them I assume to bypass
some circuit that wasn’t used like the governor control unit. Check all your connectors including those ‘caps’.
A couple of mine had corrosion on the pins. I am looking at diagrams for the 005 and wonder if you have a ‘cap’ on P31?
If so are any pins corroded?

I’ve never seen that leakage before but I doubt it would hurt anything to swap the part.

What happens to the UF light when you turn on the battle short switch?
According to the diagrams that should cause the light to go out temporarily.

I haven’t found a reason in the diagrams for the start switch to cause it to go out but I will check
more when I get a chance.

When I couldn’t find a reason my generator would not shut off when I had an over voltage problem
I started looking for wiring problems. That’s when I found my start-run-stop switch was wired to bypass some safeties. Who knows what someone may have
done to it. Anything is possible.
You can test the switch using the TM’s to verify it works.

Brian

Brian,

I'll check P31 Sunday evening. On whether the UF light goes out when the battle short switch is turned on, I can't say for sure but I almost seem to recall the UF light did not go out, but will add that to the list for a re-check. I'll also check each wire # connected to the S/S/R switch and also verify switch is per TM troubleshooting.

Thanks for the assist!

Kevin

 

[1800 Diesel]

1800 Diesel

....I haven’t found a reason in the diagrams for the start switch to cause it to go out but I will check
more when I get a chance.....You can test the switch using the TM’s to verify it works.

Brian

Brian (& others who have an interest)

Never got around to checking the P31 cap. Tested the Start/Run/Stop switch IAW TM and all open & closed circuits checked out. Then swapped out the wiring harness coming from the fault indicator panel. That did nothing. Then swapped out fault indicator panel assembly. That seems to be where the problem was. I did a 30 minute run on 7 1/2 KW load and the UF light never came on. Will repeat the test this evening as previously the problem seemed to show up after warm-up. I can't be specific as to whether the relay is at fault or a resistor or a capacitor--all these components found inside the assembly housing. Will report back tonight but I believe this gremlin has been run outta town...

Kevin

 

[flydude92]

Kevin,

Glad you were able to get it working. I hope it stays working.

It must be nice having a donor machine available. I wish I had one locally.
That would save so much time trouble shooting.

Brian

 

[1800 Diesel]

Kevin,

Glad you were able to get it working. I hope it stays working.

It must be nice having a donor machine available. I wish I had one locally.
That would save so much time trouble shooting.

Brian

Yes it's good having another unit nearby, but eventually, I do want to get it back together too. The engine looks real clean but when I got it in I found cut wiring harnesses & a couple missing switches. Overall it's a decent looking unit. But in this case, yes the spare parts nearby definitely help when troubleshooting. Already robbed a wiring harness off the same unit to correct another problem I was having on a different machine. Anyway now time to start the single phase mod and final testing & then it's paint & stencils.

 

[glassk]

OK for the few of you who work on the water-cooled models, I just did a "1st for me" light-off for this unit & I've got an under-frequency indication but freq meter is reading 60 hz. Tried to reset several times, but no change. Closed the AC breaker and tested voltage & frequency at L1, L2 & L3. All close to 120v and freq at 60 hz. Since it was getting late I didn't want to disturb too many of my fine neighbors so have shut down for the night. One thing I did do was to switch the start/run/stop switch to the start position and when I do that the under freq indicator light goes out.

Forgive me if this is a no-brainer found right in the troubleshooting section of the TM but I needed to get some supper before I dug through the manual. Will be doing that next....thanks for any ideas or comments...BTW, this unit has not been modified (yet) for the single phase re-wire....all components as found except oil & fuel & filters....

Thanks for any help sent,

Kevin

Edit--A quick-look at the schematic shows relay K12 for under freq. Once I locate it on the unit, will swap the relay out with a known good one and retest. Won't be able to run it until this coming Friday though....will report findings.

Figure 3-123. Precise Relay Assembly, Exploded View item 30 is the under frequency relay,








Table 2-2. TROUBLESHOOTING (CONTINUED)


step 9 Defective under-frequency relay K12.
Check relay K12. Replace if defective (para. 3-91).

 

[glassk]

When I responded I had not seen the photo of the DC relay, It isn't thermal paste , but looks like either someone has worked on the control relay ,

or it has been hot enough to melt the encapsulating ??

Not sure which light is staying on, although the relay for remote sensing and Start stop one are on this board I think, Long shot would be that relay is missing N/C wires or maybe dc voltage, and when you activate the start sw, it is feeding 24v that k1 is missing. looking at F0-4. AC Schematic Diagram, 15 and 30 KW, Utility Generator Sets, Drawing No. 72-2295
Utility Generator Sets, Drawing No. 72-2277




Fun fact,..

The generator set control cubicle
may be removed as a unit and installed up to 500 feet from the remainder of the set. A wiring harness with
40 AWG#16 and 7 AWG#12 conductors installed between connectors P1 and P2 (figures FO-1 and FO-2)
allows the generator set to be started, operated, and monitored from the remotely installed control cubicle.
Refer control cubicle removal and installation to higher level maintenance.

 

[1800 Diesel]

You must have missed my earlier post, but when I swapped-out the existing [leaking] TWC with a "suspected good one", there was no correction to the UF light remaining on. After a wiring harness swap (with no fix) I then swapped out the fault indicator assembly. That cleared the problem so either the relay is bad or one of the resistors or capacitors is bad or just something wrong with the board itself.

Thanks,

Kevin

 

[glassk]

Don't mind me, I'm just reading up, do you have a non-contact thermometer, while load testing, you can check the terminals and load wires for hot spots, sign of loose connections.

 

[1800 Diesel]

Don't mind me, I'm just reading up, do you have a non-contact thermometer, while load testing, you can check the terminals and load wires for hot spots, sign of loose connections.

Do have an IR thermometer. Have mainly used it for checking engine temp, exhaust & injectors & generator bearings, but will try it for checking cables & connections too. Good idea!

Thanks,

Kevin