MEP 002/003 capacitor noise filtering

[Crawdaddy]

It's common knowledge the the capacitors on the fuel pumps for the MEP 002/003 gensets fail causing control circuitry issues. It's also common knowledge that the capacitors are there to suppress noise to RF communications.

How bad is the noise with and without the capacitors and on what bands? I'm guessing it's the lower HF bands that are primarily affected by the noise, but I was wondering if anyone has any experience or data supporting where it's suppressing RF interference to help me decide whether to preemptively remove them to avoid future issues.

 

[cuad4u]

I have been HAM for 50 years - AD4U. We have used a 002A with ASK to power a multi-multi all band 160-6M legal limit field day station with no hash or RF issues. The generator is located some 100 feet from the operating positions. The fuel pumps do not have the caps in line. Your results may vary.

 

[Crawdaddy]

I operate mainly in VHF and above, so if it doesn't hurt HF, it almost certainly won't hurt VHF and above. I'll probably pull the caps just for insurance.

 

[Suprman]

The fuel pump is encased in a grounded metal housing and runs on 24 volt dc. This is isolated from the AC output. Get an oscilloscope and look at the AC output you will see spurious stuff. And you can see if it's producing a nice sine wave output.

 

[rustystud]

The capacitors are there to prevent damage to the pumps.

 

[doghead]

No they are not.

The military requested them.

Civilian units do not use them(with the same pumps).

 

[Jimc]

yes there is also one connected to the dc voltage regulator by the blower wheel. that one doesnt have to be there either and is actually broken on every generator i have seen. you can get rid of it. as far as noise on a ham radio i have no idea. the same facet fuel pump are used on aircraft and dont have a cap so i cant imagine it generating too much noise. they are loaded with electronics and com systems.

 

[rustystud]

View attachment Scan0012.pdfView attachment Scan0013.pdf

No they are not.

The military requested them.

Civilian units do not use them(with the same pumps).

Your right. I had ASSumed they where for surge protection as I have seen this used before to protect components. The Facet website shows the models and the ones used by the Military have EMI (electromagnetic interference) suppression .

 

[Wildchild467]

I had lose battery connections on my MEP-002A the other day and it shorted one of my capacitors on my fuel pumps. I knew they are failure prone so I just unhooked one of the fuel pumps since they are redundant. Then a little while later the other one blew and I saw that my battery cable was lose and arcing. I'm bummed out now because I'm back home in Michigan and my Genset is back at my Parents in NY and cant get back there until the summer to fix it. I hate having a machine down and not working. I have to research more on how to disconnect these capacitors. I am thinking I can take the cover off to where the caps are and then maybe cut the wire to the capacitor, but I have to search more on here to see what I am getting into. I know it is not that complicated. I just didn't have the time to troubleshoot it at the time.

 

[Suprman]

The old capacitors can probably be replaced with a modern equivalent component.

 

[Wildchild467]

Like Doghead said, they are not needed for operation, only noise filtering, which I can understand. I need to search and see how somebody bypassed them. I see I could cut the wire on the outside of the capacitor box and splice it, but i would like to see how it looks on the inside of the box. If I can disconnect/cut the capacitor on the inside of the box and keep the original looking intregity of the machine on the outside by not cutting wires, I would like to do that. Again, I need to search more because I am sure somebody documented it I would think. If not, then maybe somebody could show me what the inside of the capacitor box looks like and if it can be disconnected inside the box without cutting and splicing wires on the outside.

 

[rustystud]

Like Doghead said, they are not needed for operation, only noise filtering, which I can understand. I need to search and see how somebody bypassed them. I see I could cut the wire on the outside of the capacitor box and splice it, but i would like to see how it looks on the inside of the box. If I can disconnect/cut the capacitor on the inside of the box and keep the original looking intregity of the machine on the outside by not cutting wires, I would like to do that. Again, I need to search more because I am sure somebody documented it I would think. If not, then maybe somebody could show me what the inside of the capacitor box looks like and if it can be disconnected inside the box without cutting and splicing wires on the outside.

I tried to take one apart, and destroyed it in the process. So I just cut the wires and installed a military connector on it and plugged it back in.

 

[Triple Jim]

I need to search and see how somebody bypassed them.

One wire of the capacitor is connected to the 24V supply and the other is connected to ground. Simply cutting either or both wires will take them out of the circuit.

I was a big fan of leaving them in place for RF noise suppression since I'm also a ham, but since cuad4u posted evidence that noise is not severe without them, I'm less inclined to be concerned about that.

 

[Wildchild467]

Ok, thank you guys for the help and clarification. I guess I will remove them from the equation so I don't have problems again.