APU MEP-903 Maintenance and Service

[bimota]

Heads up from Program Office on the MEP-903 issues

10kW APU

MEP-903A 10kW Auxiliary Power Unit (APU), Revised Procedures for Inspection & Replacement of Fuel Filter:

• MA_10kWAPU_Fuel_Filter_RevB.pdf (Draft)

The following recommended procedure supersedes the existing fuel filter inspection and replacement procedures outlined in the 10kW APU technical manual, TM 9-6115-670-14&P in paragraph 4.30, Fuel Filter Assembly, pages 4-71 and 4-72. This notice addresses omissions and errors in the existing procedure described in the TM.
MEP-903A 10kW Auxiliary Power Unit (APU), Preventative Practices:

• MA_10kWAPU_Preventive.pdf (Draft)

This notice is recommended as preventive practice in light of recurring failures/issues associated with the MEP-903A 10kW APU. Advisory highlights recommended general preventive practices for the 10kW APU, all users. Advisory addresses oil-change intervals and use of distilled water for the radiator.


MEP-903A 10kW Auxiliary Power Unit (APU), Shock Mount Failures:

• MA_10kWAPU_SM.pdf (Draft)

This notice serves as recommended preventive practice and corrective action in light of recurring failures/issues associated with the MEP-903A 10kW APU shock mounts. Notice provides inspection procedures and replacement NSNs for resilient mounts supporting the APU engine and alternator.

MEP-903A 10kW Auxiliary Power Unit (APU), Crankcase Vent Tube Modifications:

• MA_10kWAPU_Crankcase.pdf

The procedures within this advisory are recommended as a simple, expedient modification to the crankcase vent tube on the 10kW APU to prevent the radiator from ingesting crankcase oil vapors.



Let me know if these links are not working.

 

[zoom]

Do you own one of these? I am considering one, but want to make sure its pretty solid/reliable - any tips? Do you have a good TM link? Thanks!!

 

[bimota]

Yes, I have a couple. So far, so good. Just got done reworking the control systems. Will post pictures soon.

 

[nats1380]

Speed Sensor Installment

Hello, I'm SSG Saunders. Are you familiar with how to install speed sensors/magnetic pickups on the mep 903a? I'm currently having issues trying to install one. The book states that the sensor needs to be adjusted at a minimum of 8 volts and a maximum of 18 volts but when I try to adjust the voltage to at least 8 volts I can only bring it up to a maximum of 6 volts before it starts rubbing on the flywheel. Is there something that I could have possibly missed as far as properly adjusting the flywheel? Any help concerning this would be most appreciated.

 

[bimota]

Sorry can't help with the sensors. I know all the electrics for the generator well but have not played with the engine speed sensor. The precise speed control should run on frequency of the generator and not the engine flywheel but I've not checked.

Anyone know about the slide out tray in the trucks? I need to replicate the physical slide tray on a project and would like to get some help. These unit slide into a truck and had a stand that kept them from falling to the ground.

 

[ETN550]

Hello, I'm SSG Saunders. Are you familiar with how to install speed sensors/magnetic pickups on the mep 903a? I'm currently having issues trying to install one. The book states that the sensor needs to be adjusted at a minimum of 8 volts and a maximum of 18 volts but when I try to adjust the voltage to at least 8 volts I can only bring it up to a maximum of 6 volts before it starts rubbing on the flywheel. Is there something that I could have possibly missed as far as properly adjusting the flywheel? Any help concerning this would be most appreciated.

If this is just a straight mag pickup then I have a few suggestions.

Make sure the end of the pickup is clean and not attracting any stray metal chips or filings.

Make sure it is 90 degrees square to the teeth, especially side to side. Obviously if it is in a drilled and tapped flywheel housing casting there is no error possible but if it is mounted on a bracket make sure the bracket is square and solid.

Make sure your meter is correctly reading the output as the high frequency could play games with lesser meters.

Finally, the pickup itself could be bad. It was common with pickups we used. Ours were large 3/4 diameter and about 4 inches long.

When I worked on the Superior oil and gas engines we used a lot of mag pickups. They never seemed to last very long but every now and then we would get a good one that would go for many years continous duty, 24/7.

Just some ideas..