Facet 'Cube' pump. Sudden noise on radio
Moderators: John Dean, Moderator
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cardiffrob
- Posts: 370
- Joined: Wed Jan 16, 2008 3:56 pm
Rob,
Take a look at Maplin:
Part "AT00A", 1 microfarad, 100V, axial electrolytic.
http://www.maplin.co.uk/Search.aspx?MenuNo=12473
42 pence each!
TN
Take a look at Maplin:
Part "AT00A", 1 microfarad, 100V, axial electrolytic.
http://www.maplin.co.uk/Search.aspx?MenuNo=12473
42 pence each!
TN
Disclaimer first: I'm not an electronics or vehicle wiring expert.
I have been bu99ering about with bikes, cars, planes, and basic electronic circuits for a few years, though.
Capacitors: voltage just needs to be more than any voltage likely to be applied.
Personally I wouldn't use an electrolytic cap for suppression purposes unless the noise was really bad - and then I'd probably investigate the cause rather than 'stick a plaster on it' with a suppressor. I'd probably look at using a polypropylene one. I'd imagine they are likely to be happier with the heat and vibration of an aircraft. I think they are not bothered about which way you wire them up either - electrolytics explode if you wire them up back to front (but a 1 microfarad one would be more funny than dangerous)
I stand to be corrected on any of this.
As regards the regulator Honda ones do have a chequered reputation, hence a number of after-market suppliers do them in a 'plug compatible' form.
One point before you consign this one to the scrapheap though: you have bolted the regulator to a suitable heatsink and/or made sure it has some cooling, haven't you?
With the mention of Leburg I'm guessing you are using the Honda alternator on the back/gearbox end of the VW engine. These are permanent magnet alternators that generate a voltage just by spinning with no control of the output from the alternator itself. The excess voltage (i.e. anything over 14 volts or so) is dumped by the regulator in the form of heat. This heat has to be got rid of - in the Honda regulator's case through the metal plate on the back of it and then into the bike frame.
If the regulator isn't securely mounted onto something solid and metallic to act as a heatsink, then it may well be overheating being unable to dump the excess voltage.
I'd also put a smear of silicone grease or thermal transmission compound between the regulator and it's mounting to aid heat transfer.
Incidentally, I think I'm right in saying that that the more load you put on this type of alternator installation the cooler the regulator runs. Thus, if your aircraft is a VFR daytime one with just the ignition, a radio and nowt else in the way of load your regulator will be getting hotter than if you had lights and strobes etc. Again, I stand to be corrected on this one point.
In our VP-1's Leburg installation I mounted the regulator on the 1/4" aluminium plate on the engine that had originally held the SR4 mags. This seemed to do the job admirably and had the advantage of being very close to the alternator coil's output so the three AC lines between the two were very short.
I have gone on a bit, but I hope this helps.
I have been bu99ering about with bikes, cars, planes, and basic electronic circuits for a few years, though.
Capacitors: voltage just needs to be more than any voltage likely to be applied.
Personally I wouldn't use an electrolytic cap for suppression purposes unless the noise was really bad - and then I'd probably investigate the cause rather than 'stick a plaster on it' with a suppressor. I'd probably look at using a polypropylene one. I'd imagine they are likely to be happier with the heat and vibration of an aircraft. I think they are not bothered about which way you wire them up either - electrolytics explode if you wire them up back to front (but a 1 microfarad one would be more funny than dangerous)
I stand to be corrected on any of this.
As regards the regulator Honda ones do have a chequered reputation, hence a number of after-market suppliers do them in a 'plug compatible' form.
One point before you consign this one to the scrapheap though: you have bolted the regulator to a suitable heatsink and/or made sure it has some cooling, haven't you?
With the mention of Leburg I'm guessing you are using the Honda alternator on the back/gearbox end of the VW engine. These are permanent magnet alternators that generate a voltage just by spinning with no control of the output from the alternator itself. The excess voltage (i.e. anything over 14 volts or so) is dumped by the regulator in the form of heat. This heat has to be got rid of - in the Honda regulator's case through the metal plate on the back of it and then into the bike frame.
If the regulator isn't securely mounted onto something solid and metallic to act as a heatsink, then it may well be overheating being unable to dump the excess voltage.
I'd also put a smear of silicone grease or thermal transmission compound between the regulator and it's mounting to aid heat transfer.
Incidentally, I think I'm right in saying that that the more load you put on this type of alternator installation the cooler the regulator runs. Thus, if your aircraft is a VFR daytime one with just the ignition, a radio and nowt else in the way of load your regulator will be getting hotter than if you had lights and strobes etc. Again, I stand to be corrected on this one point.
In our VP-1's Leburg installation I mounted the regulator on the 1/4" aluminium plate on the engine that had originally held the SR4 mags. This seemed to do the job admirably and had the advantage of being very close to the alternator coil's output so the three AC lines between the two were very short.
I have gone on a bit, but I hope this helps.
Rob Swain
If the good Lord had intended man to fly, He would have given him more money.
If the good Lord had intended man to fly, He would have given him more money.
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cardiffrob
- Posts: 370
- Joined: Wed Jan 16, 2008 3:56 pm
Top tips!
Thanks for those.
I haven't got a good pic of my installatin on this computer, but what I've done is to put a blast cooler from the pressure part of the cowl and Scat-hosed it to the regulator to feed air in and then cowled the regulator to help out. Maybe I need a bigger heatsink on the back of it? Thanks, I'll have another crack at it with some more ally hanging off it.
Thanks for those.
I haven't got a good pic of my installatin on this computer, but what I've done is to put a blast cooler from the pressure part of the cowl and Scat-hosed it to the regulator to feed air in and then cowled the regulator to help out. Maybe I need a bigger heatsink on the back of it? Thanks, I'll have another crack at it with some more ally hanging off it.
Rob Thomas
034851
034851