Applied Companies Trailer 23KW Gen w/HVAC Unit issues

[911joeblow]

I have been trying to bring back an Applied Companies Drash unit and am starting to get a little deeper than I like and thought I would reach out and see if you guys have experienced this stuff before.

I knew the fuel pump was bad on the Perkins when I got it so I pulled it and had it rebuilt. I had a crack in one of the hard return lines but repaired it and it is now fine too. I am now already pretty deep into this from a money standpoint just from that stuff. With the new pump the engine starts and runs fine. No matter what the electronics are doing it does not surge, hunt or fluctuate RPMs it just purrs like a kitten.

The issues start however as soon as it is started with the 4PDT relay which starts buzzing immediately on start-up regardless of switch positions etc...and the 'low fuel or stopped' LED is flashing. I have spent time in the manuals and schematics and this means the Generator has no voltage on Phase B (though the buzzing to me is not correct as it should be on or off, not buzzing between the two.) So the obvious thing to check would be the breakers on the inside of the cabinet for the generator but they are fine. I kinda want to focus on this first since I think this may be causing other issues too. I think there is a short somewhere but not sure where to start.

The generator LEDs have shown a Green LED for proper RPM and some times a Red one for Low RPM. This is likely because I dont sense that there is any electronic speed control being done if that helps? If it starts and mechanically the RPM is right, it stays there. If the RPM is low it stays there. All times though the RPMs seem reasonable nothing to low or too fast by ear.

The digital voltage meter turns on but I only get a basic menu screen and some basic info which I assume is again because I am not getting voltage from the generator. The J1 rocker switch when held up will close then open the relay on/off every second or two until I force it back off. It will not stay connected, again I assume because of the lack of voltage on one or more poles?

The 24V alternator is not charging and having done some digging I think it may have taken a hit and killed the regulator as the diode wire was burned off at the alternator. I replaced it with a good wire/diode but no luck getting it excited yet. This I am not to worried about yet as the worst case of a new alternator complete is only $80.

The HVAC unit makes some noise and tries to do things but the noises are timed with the clicking on and off of the J1 contractor so only a second then off again. I dont want to play much more with this yet until I get the voltage issue worked out.

Ever seen anything like this? Any tips? Thanks in advance!

 

[Guyfang]

I only worked on these sets a few times. But I seem to remember that they have a magnetic pickup to drive the govenor. That could be your problem with RPM. I assume, always a bad thing to do, but assume that the set has a voltage select switch, or reconnection board. In what position is it set?

 

[911joeblow]

I only worked on these sets a few times. But I seem to remember that they have a magnetic pickup to drive the govenor. That could be your problem with RPM. I assume, always a bad thing to do, but assume that the set has a voltage select switch, or reconnection board. In what position is it set?

I can check that the RPM sensor is putting out a signal. There is a three position power source select switch with OFF-GEN-SHORE. There are breakers to turn on/off different voltage outputs, and there is a contactor which engages the main load bank by electrically closing a large relay. None of these positions change the buzzing relay I have as that starts as soon as the Generator is running regardless of switch positions.

 

[Suprman]

If you dont have correct output voltage the hvac wont work. You can damage it by trying to run it. Use a multimeter to see what your output it. The regulator is mounted on top of the stator head.

 

[911joeblow]

So I did a little more digging. First I went right to the Generator head and measured the A/C output. I was getting 45-60 V at each of the three poles. It was a sine wave appearance. BUT that tells me that the A/C side is doing what it should. I then went to the D/C side and I got 24-25V DC at the alternator so I am looking good on the D/C side. Now perhaps I should still change the voltage regulator on the alternator to get 26V or so when it is charging but I can work with 24-25V.

I then measured the speed sensor output and I am getting a speed signal. I pulled the fuel control solenoid and it is hot to the touch but never seems to move the plunger. When I go to shut off the Engine I have to use the manual shutoff since the solenoid will not do it. The RUN switch to OFF and/or the emergency off will not shut the engine down. I still have two buzzing relays that buzz for a second then off a second that repeat until I shut off the engine. I am starting to think that somebody wired an A/C sensing line to the D/C side causing all this. I think the D/C relays are seeing A/C and as such none of the D/C computer controls are working like speed control, shut-off, etc...

Thoughts?

 

[Guyfang]

So hook up your multimeter to the same source that powers the relays, turn the meter to AC, and see what you get. If your DC source is rectified AC, then your filter could be bad, (popped caps). You say you are getting speed sensor out put. What are you getting?

 

[911joeblow]

So hook up your multimeter to the same source that powers the relays, turn the meter to AC, and see what you get. If your DC source is rectified AC, then your filter could be bad, (popped caps). You say you are getting speed sensor out put. What are you getting?

I will see what I can isolate in the A/C & D/C sides. The problem with D/C so close to high output A/C is that noise can often look like an A/C bleed over even though it is just noise.

The Speed signal is a typical hi/low square wave magnetic speed pickup signal. As far as actual RPM? Not sure, I would have to know the tooth count on the flywheel to do the math. I can tell you that it is likely a little low as the low speed red LED is on. I can mechanically turn up the pump to increase that but I dont think this is the issue at least right now.

 

[Guyfang]

Measure voltage at the mag pick up. Disconnect the wires, turn over the engine and read AC voltage on the two leads from the mag pickup. Should be between 2-3 volts AC. Also pull out the mag pickup and see if its covered in crap, or the end is ground off. Re adjust IAW the TM.

 

[98G]

Just a shot in the dark.... but it is possible your buzzing is that you have the aux fuel pump switched on?

 

[911joeblow]

Just a shot in the dark.... but it is possible your buzzing is that you have the aux fuel pump switched on?

Nope, and I could actually see the relays buzzing!

 

[911joeblow]

Measure voltage at the mag pick up. Disconnect the wires, turn over the engine and read AC voltage on the two leads from the mag pickup. Should be between 2-3 volts AC. Also pull out the mag pickup and see if its covered in crap, or the end is ground off. Re adjust IAW the TM.

I pulled the sensor which had some light debris on it mostly shavings and metal dust. I cleaned it an reset the depth. Both before and after I am getting a good speed signal.

 

[911joeblow]

So I think one thing I am fighting is base engine speed. The engine wants to idle at low RPM. If I manually accelerate the engine and jamb something into the throttle to hold it there, I get a green LED and I can fire up the A/C unit on blower or heat (no refrigerant) and everything is great now. The alternator starts charging too at the higher RPMs so that is good. But what is still not working is I dont sense any speed control and when I go to shut down the solenoid does nothing and I have to manually close the shut valve. So it would seem I am still without speed control and electronic shut down.

Is there a write up on setting the base idle speed for this Perkins that anybody had available? I think I need to get that settled to make this rest of this go well. Is there a step-by-step on the speed control system?