Voltage Regulator Failed

[Blueadventures]

13 minutes ago, BurnieM said:

How much is a new rec/reg ?

 

Buying a new one and trying it would save a lot of time and 'pointsforpilots.blogspot' recommends Rotax owners carry a spare regardless.

 

 

Agree, a worthwhile spare to have.  I normally carry two new (Rotax ones) as spares but down to one at moment as awaiting availability of a new after market make that’s under testing. As I do a fair bit of servicing and troubleshooting 912 issues I need to supply Rotax parts in my work. Some have given intermittent failure at under 350 hours from experience.

 

All multimeter checks are best compared with the specs listed in the Rotax manual.  I see it as foolish to not apply such data when trouble shooting; however very aware many do such.

[skippydiesel]

"Some have given intermittent failure at under 350 hours from experience."

 

Is this a statement about  Rotax parts failure in general or are you still on topic - VR failures?

 

What are the symptoms of a VR "intermittent " failure?

 

Premature VR failures have been a problem for Rotax 9's since the introduction of the engine. Several modifications later, they are still failing in significant numbers. The Rotax party line has always blamed the installer/user - too hot, too much vibration. The reality is that the Rotax/Ducati VR is not and has never been "up to scratch". Independent investigators highlight poor construction/quality control, as the likly cause of early failure in the current iteration. Failures can occur from under 100 hrs (Hobbs) to any time up to several hundred hour. Mine failed at 153 hrs.

 

Factory built aircraft. legally must use the Rotax/Ducati VR. Home builds can and do look to alternatives, which may prove more durable.

 

Check out just some of the correspondence on the Rotax Owners Forum & you will find that  the Rotax/Ducati VR problem goes back to the 1990's and continues to this day.😈

 

[danny_galaga]

2 hours ago, BurnieM said:

How much is a new rec/reg ?

 

Buying a new one and trying it would save a lot of time and 'pointsforpilots.blogspot' recommends Rotax owners carry a spare regardless.

 

 

You do have to be wary. Plugging in a new one into something that caused the old one to fail is an expensive diagnosis 😄

[skippydiesel]

Well I got the new VR in today. Much bad language, some pain and not a little satisfaction. Will do the engine run tomorrow - fingers crossed😈

[skippydiesel]

CARMO CARR5005 MOSFET working like a charm.

14.5V - amps vary according to demand, from 12 down to 1 amp

Temperature up to 38C 

Happy pilot 😈

 

[BurnieM]

https://www.vectriqparts.com.au/product/rotax-voltage-regulator-carr5115/

 

Did the wiring take much time/effort ?

 

[skippydiesel]

2 hours ago, BurnieM said:

https://www.vectriqparts.com.au/product/rotax-voltage-regulator-carr5115/

 

Did the wiring take much time/effort ?

 

No the wiring is straight forward - just be sure that connections are good & tight. There is a excellent diagram + specifications on the web site.

 

NOTE: The CARMO has  (from memory) mounting holes at 65mm centres and the Rotax 92 mm.  You will need to drill an extra hole or make up an adapter as I did:

Black top, with spout, secured in place with safety wire, is part of the dedicated cooling system.

Rectangular aluminium tube (drilled for air flow) is the adapter .

Black wire, (TOP) with yellow connector is to ensure good negative contact - I also cleaned of the black paint around the mounting holes & used a smear of dialectic grease. 😈

[sfGnome]

Is the cooling cap a Sonex thing or a Skippy thing? Where are you picking up the airflow that you’re feeding to it?

[skippydiesel]

1 hour ago, sfGnome said:

Is the cooling cap a Sonex thing or a Skippy thing? Where are you picking up the airflow that you’re feeding to it?

Bits & pieces from here & there.

 

Sonex are still new to Rotax installations, so no ideas from this direction

• The idea came from VR problems/solutions in RV12's
• The cap was made to order/design, by my Son on his 3D printer.
• The fresh air supply is through SCAT tube from a T piece, to the cooling cap, in the cabin left hand fresh air vent.

Down side with the above -  in winter there is a nasty draft from it onto my ankles. I have reduced this discomfort by putting a short piece of hose (a choke)  in the air duct (SCAT tube) thereby reducing the air flow. The choke will be removed for summer flying.

😈

[danny_galaga]

My installation benefitted from being a clean install. Plenty of air movement around the device, but the air that's there isn't going to be very cool. That's the kit position and I didn't want to waste time doing something different. Anyway, my hope was that even it's a bit warm there, it's supposed to run cooler than the original anyway. So far the longest flight has been roughly 80 minutes 

 

[skippydiesel]

Hi Danny,

 

Good idea to raise the VR off the mounting surface - just be sure that its making a very good earth contact.😈

[Red]

Whilst it's common for VRs to require the case to be grounded the Carmo makes no mention of doing this.

Also did you connect it direct to the battery with no fuse as the Carmo instructions indicate?

[skippydiesel]

1 hour ago, Red said:

Whilst it's common for VRs to require the case to be grounded the Carmo makes no mention of doing this.

Also did you connect it direct to the battery with no fuse as the Carmo instructions indicate?

I am a big believer in good grounding for 12 V systems. Sure CARMO make no mention of the need however it cant do any harm & may help.

 

Connected to battery - through 25 amp fuse as per Rotax recommended practise. I only have one circuit not protected by either a fuse or a circuit breaker. The one is my external battery charge / jump/ supply port😈

[danny_galaga]

20 hours ago, Red said:

Whilst it's common for VRs to require the case to be grounded the Carmo makes no mention of doing this.

Also did you connect it direct to the battery with no fuse as the Carmo instructions indicate?

Yeah, I figure since the Carmo is made for aircraft it's fully above ground electrically. The Ducati one obviously is for motorbikes which use the frame for negative ground.

[Underwood]

My Carmo install goes through master switch and fuse to battery.
I didnt pay attention to grounding the case as I assumed it was not actually electrically connected to any internal components but was merely a heatsink.
Maybe I should go back on that?
I suppose checking for continuity between the negative wire from the regu and the case would confirm whether or not grounding the case provides any purpose electrically for the carmo?