JPI 930 Display Questio

[Speed Merchant]

I recently purchased a 1984 M20j. I installed a JPI 930, Whelen nav/strobes, BoomBeam and the LoPresti Cowling. The 930 is awesome. I removed the stock engine gages except for the cluster gages at the top of the pilot panel. Late this year I am going to install a G3X , a G5 and a GFC--500 and replace the pilot panel. My question is that the ammeter show a current draw change almost constantly. It is normal ? Maybe it is telling me that I have a alternator issue? I am new to MooneySpace, I will be listing all of the stuff I removed on the site.Thanks!

 

[carusoam]

Welcome aboard, Speed!

plan on posting pics of the old and the new...

Some of the process is easy, some of it is a challenge...

Add some data to your avatar area... where you are will be helpful...

Best regards,

-a-

[cferr59]

What is the delta?  What do you have on?  If you have a flashing beacon, it will cause the amperage to fluctuate.  I would start by turning things off switches and pulling breakers until it stops.  My 930 stays pretty steady unless I have the LED flashing beacon on.

[Speed Merchant]

I live in Vero Beach, Florida. I recently retired from the aircraft modification business. It took me two years to find the right Mooney 201. I am very happy with it!

[Speed Merchant]

It draw seems to change constantly. I do not remember the delta. I had the avionics master on. I tried increasing the draw with the pitot heat. It was about 1800 rpm. I just put a new cylinder on and did not want an extended ground run. I broke the cowl flap control during rigging the flaps during the new cowl installation. As soon as I get the new control in I will fly it and see what happens. I will post the results.

Thanks

[Speed Merchant]

31 minutes ago, carusoam said:

Welcome aboard, Speed!

plan on posting pics of the old and the new...

Some of the process is easy, some of it is a challenge...

Add some data to your avatar area... where you are will be helpful...

Best regards,

-a-

Thanks appreciate the welcome!

[carusoam]

Things to look for with the amperage reading fluctuating...

It could be real...

Or it could be a function of the instrumentation...

Often the instrumentation is affected by the quality of the panel grounding...

Lots of cleaning of grounds connections, and ground straps can be helpful...

The amp reading, as you are probably familiar... Is a voltage reading across a large resistor called a shunt...

At low rpm, voltage produced by the alternator may be a bit funky...

The alternator’s diode bridge may be aged as well, adding some noise to the situation... got any rpm sensitive whining going on in the audio panel system?

PP thoughts only, all stuff I read about on MS...

Best regards,

-a-

[Speed Merchant]

On 6/10/2020 at 8:43 PM, carusoam said:

Things to look for with the amperage reading fluctuating...

It could be real...

Or it could be a function of the instrumentation...

Often the instrumentation is affected by the quality of the panel grounding...

Lots of cleaning of grounds connections, and ground straps can be helpful...

The amp reading, as you are probably familiar... Is a voltage reading across a large resistor called a shunt...

At low rpm, voltage produced by the alternator may be a bit funky...

The alternator’s diode bridge may be aged as well, adding some noise to the situation... got any rpm sensitive whining going on in the audio panel system?

PP thoughts only, all stuff I read about on MS...

Best regards,

-a-

Thanks for the contact- as soon as I fly it I will have some better data.

[Marauder]

I recently purchased a 1984 M20j. I installed a JPI 930, Whelen nav/strobes, BoomBeam and the LoPresti Cowling. The 930 is awesome. I removed the stock engine gages except for the cluster gages at the top of the pilot panel. Late this year I am going to install a G3X , a G5 and a GFC--500 and replace the pilot panel. My question is that the ammeter show a current draw change almost constantly. It is normal ? Maybe it is telling me that I have a alternator issue? I am new to MooneySpace, I will be listing all of the stuff I removed on the site.Thanks!

 

 

There are two ways the ammeter can be wired. Either as an ammeter or as a load meter. If you don’t have an installation manual, you can use this link.

 

 

https://www.jpinstruments.com/wp-content/uploads/2012/08/Install908-Primary_REV-K-4-18-2017jfp.pdf

 

 

 

Sent from my iPhone using Tapatalk Pro

[Speed Merchant]

On 6/12/2020 at 9:37 PM, Marauder said:

 

There are two ways the ammeter can be wired. Either as an ammeter or as a load meter. If you don’t have an installation manual, you can use this link.

 

 

https://www.jpinstruments.com/wp-content/uploads/2012/08/Install908-Primary_REV-K-4-18-2017jfp.pdf

 

 

 

Sent from my iPhone using Tapatalk Pro

Thank you very much for the information. I will find out which I have.

[FloridaMan]

On 6/10/2020 at 8:27 PM, Speed Merchant said:

I live in Vero Beach, Florida. I recently retired from the aircraft modification business. It took me two years to find the right Mooney 201. I am very happy with it!

Curt? 

[jlunseth]

The Delta is a good question. I have a 930 and have for about a decade. The ammeter reading fluctuates constantly, but it is not a large fluctuation, it is a few amps. The instrument is sensitive. I know next to nothing about electrical systems, but the way it looks to me the system is bringing the battery up to a full charge and then is making constant small adjustments to keep up with draw changes and to keep the battery topped off but not overcharged. Maybe the volatage regulator is doing that? I wouldn’t worry about it unless you are getting big changes or the buss voltage is falling into the negative and staying there even at cruise engine speeds. 

[carusoam]

I thought there may be an infringement challenge for somebody showing up as a Speed Merchant....
 

Not just anybody can be a speed merchant! 

Roy’s Image showed up here the other day... in front of a fancy Mooney...

Now... A fancy Mooney 201, sporting a LoPresti cowl with a BoomBeam, being touted as the right Mooney...

Hmmmm...  I think a Florida Man is hot on the trail....

Welcome aboard Curt!
 

Best regards,

-a-

[Speed Merchant]

Thanks for the picture of my Dad. He started putting me in T6s and T33s before I could walk. I never really had a chance! I worked with him on the development of the 201 starting in 1974 in the experimental shop. I had a customer surfboard business prior to moving to Kerrville and was good at shaping things and making molds. I built some of the original 201 mods-first slopped windshield and some of the fairings. I then worked in the flight test and structures department while I was getting my engineering degree. Mooneys are a part of our family. I was very happy to finally get my own.

Curt

PS I just saw your post today.

 

[carusoam]

Roy L. brought the efficiency of aerodynamics to Kerrville!

All those fancy curved fiberglass shapes to get 201mph started with Roy...

It was the return of composite parts for Mooney...

Return, because the original wings of the M20 were originally built from nature’s best composite material... wood! 

Thanks for sharing the family details....

Best regards,

-a-

[Mooney in Oz]

20 hours ago, Speed Merchant said:

Thanks for the picture of my Dad. He started putting me in T6s and T33s before I could walk. I never really had a chance! I worked with him on the development of the 201 starting in 1974 in the experimental shop. I had a customer surfboard business prior to moving to Kerrville and was good at shaping things and making molds. I built some of the original 201 mods-first slopped windshield and some of the fairings. I then worked in the flight test and structures department while I was getting my engineering degree. Mooneys are a part of our family. I was very happy to finally get my own.

Curt

PS I just saw your post today.

 

That is awesome Curt. Hats off to you and your late dad.

You must feel very proud to have been a part of the development of a great legacy that we enjoy today, one of which you now personally own.

Did you ever get the privilege to meet Al Mooney?

[jlunseth]

Welcome Curt! Really cool to have you here.

A PS on my prior post. Having flown with a 930 for quite awhile I have noticed that generally, it is much more sensitive than the factory gauges it replaced.  You could not see changes of 10 RPMs, for example, on the old gauge, or maybe you could but needed a microscope, but the 930 puts out a number and very quickly. Same with virtually all the things that are instantaneously sensed rather than an averaging of some kind. Perhaps there is a better engineering term for it but what I am trying to explain is that CHT, for example, is the temp that the cylinder metal is heated to and although it is subjected to many wild variations in combustion and exhaust temps it tends to move slowly. MP, fuel flow, amps, EGTs and a few others tend to move around quite a bit, although in a narrow range. They are the ones I am calling “instantanteous.” The old analog dials did not move with the speed of change that the 930 does. And so when you see fuel flow, for example, fluctuating a few tenths, yes it would be nice if the system itself were a little more stable but it is an old mechanical system, not perfect to the tenth and wasn’t even when it was designed, but it doesn’t mean much that the water wheel ticks up and down a little. On my panel the amps appear to be one of those, very instantaneously read, small changes going on constantly. Its been that way for ten years or so and through several couplers, at least two alternators. So I think it is an indication issue not a system issue.

[jlunseth]

PPSS I ran across a good article about ammeter fluctuation on Maxwell Aviation’s website. https://www.donmaxwell.com/fluctuating-ammeters If the link does not work, it is under Published Articles.

Edited August 26, 2020 by jlunseth

[Speed Merchant]

On 8/19/2020 at 10:24 PM, carusoam said:

Roy L. brought the efficiency of aerodynamics to Kerrville!

All those fancy curved fiberglass shapes to get 201mph started with Roy...

It was the return of composite parts for Mooney...

Return, because the original wings of the M20 were originally built from nature’s best composite material... wood! 

Thanks for sharing the family details....

Best regards,

-a-

Thanks very much- Roy was an awesome human being- I miss him every day.

[Speed Merchant]

On 8/20/2020 at 9:22 AM, Mooney in Oz said:

That is awesome Curt. Hats off to you and your late dad.

You must feel very proud to have been a part of the development of a great legacy that we enjoy today, one of which you now personally own.

Did you ever get the privilege to meet Al Mooney?

Yes I did my brother Jim was his engineering assistant on the Avtec 400. What a man! I visited him in his home near the Mooney plant.

[carusoam]

Very interesting...

Al Mooney designed Avtek400...

https://en.wikipedia.org/wiki/Avtek_400A

Later became the avtek9000 

Pictured flying here...

Highlights...

• Canard 
• Composite
• Turbine
• twin

Sounds like Al Mooney modus operandi?

Best regards,

-a-