Today's Message Index:
----------------------
1. 01:00 PM - heater fan wiring (Ken Ryan)
2. 02:15 PM - Re: heater fan wiring (user9253)
3. 02:58 PM - Re: heater fan wiring (Charlie England)
4. 03:36 PM - Re: heater fan wiring (Ken Ryan)
5. 03:45 PM - Re: Re: heater fan wiring (Ken Ryan)
6. 05:07 PM - Re: heater fan wiring (user9253)
7. 05:11 PM - Re: Re: heater fan wiring (Eric Page)
8. 06:01 PM - Re: Re: heater fan wiring (Bernie Willis)
9. 06:02 PM - Re: heater fan wiring (Kent or Jackie Ashton)
10. 06:51 PM - Re: heater fan wiring (Craig L. Reding)
11. 07:27 PM - Re: headset matching to radio (Dana)
Message 1
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| Subject: | heater fan wiring |
I am building a cabin heater (Rotax) and the fan draws 4.3 amps. I have
read that on startup it can draw 12 amps. It is a permanent magnet type
fan. It looks like a large computer fan on steroids.
I have decided to use my "defrost" circuit, which was originally going to
power a couple of small, low draw computer fans. I wired it with 20 AWG
wire.
I would like to use the existing wiring for the fan, but I might need to
put in a 12 amp fuse, and am a little concerned that might be too much for
the 20 AWG wire.
The wire from the bus to the switch is about 18 inches and the wire from
the switch to the fan is about 24 inches.
I guess I have two questions:
1. What would be the largest fuse I could use and still be safe?
2. If I test it and it doesn't blow a 5 amp (or 7.5 amp) fuse, do you think
it would be likely to continue working indefinitely?
Thanks,
Ken
Message 2
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| Subject: | Re: heater fan wiring |
I would try a 7.5 amp fuse. I usually prefer fuses. But for a motor,
a circuit breaker will not nuisance trip as easily. Some day the motor
bearings will freeze up. If fused higher and the motor draws 12 amps continuously,
the wire will then get hot enough to boil water.
How hard is it to replace the wire? Sometimes it is easier to go ahead
and do it the hard way to start with. When faced with a decision like this,
I ask myself, what is best in the long run, not what is easiest right now.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=467764#467764
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| Subject: | Re: heater fan wiring |
On 3/28/2017 2:49 PM, Ken Ryan wrote:
> I am building a cabin heater (Rotax) and the fan draws 4.3 amps. I
> have read that on startup it can draw 12 amps. It is a permanent
> magnet type fan. It looks like a large computer fan on steroids.
>
> I have decided to use my "defrost" circuit, which was originally going
> to power a couple of small, low draw computer fans. I wired it with 20
> AWG wire.
>
> I would like to use the existing wiring for the fan, but I might need
> to put in a 12 amp fuse, and am a little concerned that might be too
> much for the 20 AWG wire.
>
> The wire from the bus to the switch is about 18 inches and the wire
> from the switch to the fan is about 24 inches.
>
> I guess I have two questions:
>
> 1. What would be the largest fuse I could use and still be safe?
>
> 2. If I test it and it doesn't blow a 5 amp (or 7.5 amp) fuse, do you
> think it would be likely to continue working indefinitely?
>
> Thanks,
>
> Ken
Somebody on another forum recently posted a link to Cooper Bussman ATC
format circuit breakers. The time-to-trip vs overload percentage looks a
lot like traditional circuit breakers, instead of the near-instant trip
of an ATC fuse. Might be worth a look. The longer time constant should
allow for momentary startup loads.
http://www.cooperindustries.com/content/dam/public/bussmann/Transportation/Resources/catalog_pages/BUS_Tns_227_ATC_CB.pdf
http://www.cooperindustries.com/content/dam/public/bussmann/Transportation/Resources/catalog_pages/circuit-protection/bus-cbt-ds-series-22x-circuit-breakers.pdf
That's a really sturdy looking fan box. :-) What's it weigh?
Charlie
Message 4
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| Subject: | Re: heater fan wiring |
Charlie, it weighs 3 pounds 14 ounces, but that does not include hoses or
fittings (or the additional fluid required). I estimate 5.5 pounds all
told, 6 pounds maximum. The stuff that I will be removing (heater box, scat
tubing, cables, etc. weighs about 3 pounds, so 2 or 3 pounds heavier the
airplane will be.
To me this is a no-brainer, as I look upon the typical method of scavenging
off the exhaust as a kind of Sword of Damocles, always poised to kill you.
Plus, I live in Alaska! Lots of cold weather flying, so a better heater is
really appreciated.
So anyway, I got my speed control this morning. I hooked it all up and
tried to blow the 5 amp fuse. I was not successful.
I am thinking that maybe the information that I read about 12 amp startup
draw is bogus. As I said, this is a permanent magnet type motor, very
similar to what I have seen on computers. Does this type of motor really
have large startup loads?
So now that I have tried and failed to blow the 5 amp fuse, unless this
list implores me to rewire for safety, I will stick with the 20 AWG.
I'm pretty sure Bob has said that there is no problem using a 7.5 amp fuse
with 20 AWG, right? If I did blow the 5 amp, I would still have the 7.5 amp
fuse option.
Ken
On Tue, Mar 28, 2017 at 1:57 PM, Charlie England <ceengland7@gmail.com>
wrote:
> ceengland7@gmail.com>
>
>
> On 3/28/2017 2:49 PM, Ken Ryan wrote:
>
>> I am building a cabin heater (Rotax) and the fan draws 4.3 amps. I have
>> read that on startup it can draw 12 amps. It is a permanent magnet type
>> fan. It looks like a large computer fan on steroids.
>>
>> I have decided to use my "defrost" circuit, which was originally going to
>> power a couple of small, low draw computer fans. I wired it with 20 AWG
>> wire.
>>
>> I would like to use the existing wiring for the fan, but I might need to
>> put in a 12 amp fuse, and am a little concerned that might be too much for
>> the 20 AWG wire.
>>
>> The wire from the bus to the switch is about 18 inches and the wire from
>> the switch to the fan is about 24 inches.
>>
>> I guess I have two questions:
>>
>> 1. What would be the largest fuse I could use and still be safe?
>>
>> 2. If I test it and it doesn't blow a 5 amp (or 7.5 amp) fuse, do you
>> think it would be likely to continue working indefinitely?
>>
>> Thanks,
>>
>> Ken
>>
> Somebody on another forum recently posted a link to Cooper Bussman ATC
> format circuit breakers. The time-to-trip vs overload percentage looks a
> lot like traditional circuit breakers, instead of the near-instant trip of
> an ATC fuse. Might be worth a look. The longer time constant should allow
> for momentary startup loads.
> http://www.cooperindustries.com/content/dam/public/bussmann/
> Transportation/Resources/catalog_pages/BUS_Tns_227_ATC_CB.pdf
>
> http://www.cooperindustries.com/content/dam/public/bussmann/
> Transportation/Resources/catalog_pages/circuit-
> protection/bus-cbt-ds-series-22x-circuit-breakers.pdf
>
> That's a really sturdy looking fan box. :-) What's it weigh?
>
> Charlie
>
>
Message 5
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| Subject: | Re: heater fan wiring |
That's a good point Joe. Update: I got it all hooked up (temporary) and it
works great with a 5 amp fuse, so I think I will be okay. If necessary I
will go to 7.5 amp, but I won't go higher than that. Do these type motors
really have large startup current requirements? Would it make any
difference that I am running it through a PWM speed control? Like I said, I
am not blowing a 5 amp fuse.
On Tue, Mar 28, 2017 at 1:12 PM, user9253 <fransew@gmail.com> wrote:
>
> I would try a 7.5 amp fuse. I usually prefer fuses. But for a motor,
> a circuit breaker will not nuisance trip as easily. Some day the motor
> bearings will freeze up. If fused higher and the motor draws 12 amps
> continuously,
> the wire will then get hot enough to boil water.
> How hard is it to replace the wire? Sometimes it is easier to go ahead
> and do it the hard way to start with. When faced with a decision like
> this,
> I ask myself, what is best in the long run, not what is easiest right now.
>
> --------
> Joe Gores
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=467764#467764
>
>
Message 6
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| Subject: | Re: heater fan wiring |
Ken, Some fan speed controllers put out a steady DC for several milliseconds to
start a motor, then change over to PWM. The motor might very well draw 12 amps
to start, but only for a fraction of a second, too short of a time to heat
up and blow a fuse. It looks like you have answered your own question by testing.
As long as it works, it is good enough.
Thanks for those links Charlie. I never knew ATC circuit breakers existed.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=467771#467771
Message 7
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| Subject: | Re: heater fan wiring |
Does your speed control have a power on/off switch separate from the speed knob,
or do you twist the speed knob from the "off" detent to the lowest speed setting,
and up from there?
If the former, then it's possible to start the fan in its highest draw setting
(PWM at 100%). If the latter, it will always turn on at the lowest PWM value,
so inrush should be well controlled (unless you slam the knob to max speed, I
suppose).
In either case, the speed control may have inrush limiting as part of its design.
The best way to check this issue for sure is a DC clamp meter or series-connected
ammeter with max-hold function.
Eric
> On Mar 28, 2017, at 3:39 PM, Ken Ryan <keninalaska@gmail.com> wrote:
> [SNIP] Do these type motors really have large startup current requirements?
Would it make any difference that I am running it through a PWM speed control?
Like I said, I am not blowing a 5 amp fuse.
Message 8
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| Subject: | Re: heater fan wiring |
This question is about USB charging ports and radio interference/noise.
Ive check out a couple charging ports that plug into the cigarette lighter and
they both produce noise when charging. Both purchased from pilot shops. Also
tried a couple direct wire USB charging ports from marine/auto applications with
the same result. Is there any way to filter or shield these devices to reduce
or eliminate the radio noise. The noise cant be eliminated with squelch adjustment.
Im using a hand held icom radio for the test, it doesnt see to make
any difference if the radio is 12 to 36 away from the charging port.
Thanks,
Bernie
> On Mar 28, 2017, at 4:01 PM, user9253 <fransew@gmail.com> wrote:
>
>
> Ken, Some fan speed controllers put out a steady DC for several milliseconds
to start a motor, then change over to PWM. The motor might very well draw 12
amps to start, but only for a fraction of a second, too short of a time to heat
up and blow a fuse. It looks like you have answered your own question by testing.
As long as it works, it is good enough.
> Thanks for those links Charlie. I never knew ATC circuit breakers existed.
>
> --------
> Joe Gores
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=467771#467771
>
>
>
>
>
>
>
>
>
Message 9
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| Subject: | Re: heater fan wiring |
I understand the desire for a good heater but running lean of peak minimizes
the carbon monoxide
> On Mar 28, 2017, at 6:32 PM, Ken Ryan <keninalaska@gmail.com> wrote:
>
> Charlie, it weighs 3 pounds 14 ounces, but that does not include hoses or f
ittings (or the additional fluid required). I estimate 5.5 pounds all told, 6
pounds maximum. The stuff that I will be removing (heater box, scat tubing,
cables, etc. weighs about 3 pounds, so 2 or 3 pounds heavier the airplane w
ill be.
>
> To me this is a no-brainer, as I look upon the typical method of scavengin
g off the exhaust as a kind of Sword of Damocles, always poised to kill you.
Plus, I live in Alaska! Lots of cold weather flying, so a better heater is r
eally appreciated.
>
> So anyway, I got my speed control this morning. I hooked it all up and tri
ed to blow the 5 amp fuse. I was not successful.
>
> I am thinking that maybe the information that I read about 12 amp startup d
raw is bogus. As I said, this is a permanent magnet type motor, very similar
to what I have seen on computers. Does this type of motor really have large
startup loads?
>
> So now that I have tried and failed to blow the 5 amp fuse, unless this li
st implores me to rewire for safety, I will stick with the 20 AWG.
>
> I'm pretty sure Bob has said that there is no problem using a 7.5 amp fuse
with 20 AWG, right? If I did blow the 5 amp, I would still have the 7.5 amp
fuse option.
>
> Ken
>
>> On Tue, Mar 28, 2017 at 1:57 PM, Charlie England <ceengland7@gmail.com> w
rote:
l.com>
>>
>>
>>> On 3/28/2017 2:49 PM, Ken Ryan wrote:
>>> I am building a cabin heater (Rotax) and the fan draws 4.3 amps. I have r
ead that on startup it can draw 12 amps. It is a permanent magnet type fan. I
t looks like a large computer fan on steroids.
>>>
>>> I have decided to use my "defrost" circuit, which was originally going t
o power a couple of small, low draw computer fans. I wired it with 20 AWG wi
re.
>>>
>>> I would like to use the existing wiring for the fan, but I might need to
put in a 12 amp fuse, and am a little concerned that might be too much for t
he 20 AWG wire.
>>>
>>> The wire from the bus to the switch is about 18 inches and the wire from
the switch to the fan is about 24 inches.
>>>
>>> I guess I have two questions:
>>>
>>> 1. What would be the largest fuse I could use and still be safe?
>>>
>>> 2. If I test it and it doesn't blow a 5 amp (or 7.5 amp) fuse, do you th
ink it would be likely to continue working indefinitely?
>>>
>>> Thanks,
>>>
>>> Ken
>> Somebody on another forum recently posted a link to Cooper Bussman ATC fo
rmat circuit breakers. The time-to-trip vs overload percentage looks a lot l
ike traditional circuit breakers, instead of the near-instant trip of an ATC
fuse. Might be worth a look. The longer time constant should allow for mome
ntary startup loads.
>> http://www.cooperindustries.com/content/dam/public/bussmann/Transportatio
n/Resources/catalog_pages/BUS_Tns_227_ATC_CB.pdf
>>
>> http://www.cooperindustries.com/content/dam/public/bussmann/Transportatio
n/Resources/catalog_pages/circuit-protection/bus-cbt-ds-series-22x-circuit-b
reakers.pdf
>>
>> That's a really sturdy looking fan box. :-) What's it weigh?
>>
>> Charlie
>> =========================
>> -
>> Electric-List" rel="noreferrer" target="_blank">http://www.matronics.
com/Navigator?AeroElectric-List
>> =========================
>> FORUMS -
>> eferrer" target="_blank">http://forums.matronics.com
>> =========================
>> WIKI -
>> errer" target="_blank">http://wiki.matronics.com
>> =========================
>> b Site -
>> -Matt Dralle, List Admin.
>> rel="noreferrer" target="_blank">http://www.matronics.com/contributio
n
>> =========================
>
Message 10
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| Subject: | Re: heater fan wiring |
> On Mar 28, 2017, at 8:58 PM, Kent or Jackie Ashton <kjashton@vnet.net>
wrote:
>
> I understand the desire for a good heater but running lean of peak
minimizes the carbon monoxide
>
> On Mar 28, 2017, at 6:32 PM, Ken Ryan <keninalaska@gmail.com
<mailto:keninalaska@gmail.com>> wrote:
>
>> Charlie, it weighs 3 pounds 14 ounces, but that does not include
hoses or fittings (or the additional fluid required). I estimate 5.5
pounds all told, 6 pounds maximum. The stuff that I will be removing
(heater box, scat tubing, cables, etc. weighs about 3 pounds, so 2 or 3
pounds heavier the airplane will be.
>>
>> To me this is a no-brainer, as I look upon the typical method of
scavenging off the exhaust as a kind of Sword of Damocles, always poised
to kill you. Plus, I live in Alaska! Lots of cold weather flying, so a
better heater is really appreciated.
>>
>> So anyway, I got my speed control this morning. I hooked it all up
and tried to blow the 5 amp fuse. I was not successful.
>>
>> I am thinking that maybe the information that I read about 12 amp
startup draw is bogus. As I said, this is a permanent magnet type motor,
very similar to what I have seen on computers. Does this type of motor
really have large startup loads?
>>
>> So now that I have tried and failed to blow the 5 amp fuse, unless
this list implores me to rewire for safety, I will stick with the 20
AWG.
>>
>> I'm pretty sure Bob has said that there is no problem using a 7.5 amp
fuse with 20 AWG, right? If I did blow the 5 amp, I would still have the
7.5 amp fuse option.
>>
>> Ken
>>
>> On Tue, Mar 28, 2017 at 1:57 PM, Charlie England
<ceengland7@gmail.com <mailto:ceengland7@gmail.com>> wrote:
<ceengland7@gmail.com <mailto:ceengland7@gmail.com>>
>>
>>
>> On 3/28/2017 2:49 PM, Ken Ryan wrote:
>> I am building a cabin heater (Rotax) and the fan draws 4.3 amps. I
have read that on startup it can draw 12 amps. It is a permanent magnet
type fan. It looks like a large computer fan on steroids.
>>
>> I have decided to use my "defrost" circuit, which was originally
going to power a couple of small, low draw computer fans. I wired it
with 20 AWG wire.
>>
>> I would like to use the existing wiring for the fan, but I might need
to put in a 12 amp fuse, and am a little concerned that might be too
much for the 20 AWG wire.
>>
>> The wire from the bus to the switch is about 18 inches and the wire
from the switch to the fan is about 24 inches.
>>
>> I guess I have two questions:
>>
>> 1. What would be the largest fuse I could use and still be safe?
>>
>> 2. If I test it and it doesn't blow a 5 amp (or 7.5 amp) fuse, do you
think it would be likely to continue working indefinitely?
>>
>> Thanks,
>>
>> Ken
>> Somebody on another forum recently posted a link to Cooper Bussman
ATC format circuit breakers. The time-to-trip vs overload percentage
looks a lot like traditional circuit breakers, instead of the
near-instant trip of an ATC fuse. Might be worth a look. The longer time
constant should allow for momentary startup loads.
>>
http://www.cooperindustries.com/content/dam/public/bussmann/Transportation
/Resources/catalog_pages/BUS_Tns_227_ATC_CB.pdf
<http://www.cooperindustries.com/content/dam/public/bussmann/Transportatio
n/Resources/catalog_pages/BUS_Tns_227_ATC_CB.pdf>
>>
>>
http://www.cooperindustries.com/content/dam/public/bussmann/Transportation
/Resources/catalog_pages/circuit-protection/bus-cbt-ds-series-22x-circuit-
breakers.pdf
<http://www.cooperindustries.com/content/dam/public/bussmann/Transportatio
n/Resources/catalog_pages/circuit-protection/bus-cbt-ds-series-22x-circuit
-breakers.pdf>
>>
>> That's a really sturdy looking fan box. :-) What's it weigh?
>>
>> Charlie
>> ========================
===========
>> -
>> Electric-List" rel="noreferrer"
target="_blank">http://www.matronics.com/Navig
<http://www.matronics.com/Navig>ator?AeroElectric-List
>> ========================
===========
>> FORUMS -
>> eferrer" target="_blank">http://forums.matronics.com
<http://forums.matronics.com/>
>> ========================
===========
>> WIKI -
>> errer" target="_blank">http://wiki.matronics.com
<http://wiki.matronics.com/>
>> ========================
===========
>> b Site -
>> -Matt Dralle, List Admin.
>> rel="noreferrer" target="_blank">http://www.matronics.com/contr
<http://www.matronics.com/contr>ibution
>> ========================
===========
>>
>>
>>
>>
Message 11
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| Subject: | Re: headset matching to radio |
I haven't picked up the plane yet, but I have a system I'm confident will work.
On one side, an impedance matching transformer to convert the 8 ohm earphones
for a receiver output expecting 300 ohms, and for the mike side, rather than
working out an amplifier I bought a new replacement noise cancelling mike element
from Aircraft Spruce. Wired to the appropriate connectors, I've verified
they work, at least with the radio in a friend's Bonanza. Interestingly, they
also work with the Icom handheld in my old plane... I guess the Icom is a lot
more tolerant than the older radios.
As for the "why", I use the earbuds because they fit under a leather flying helmet.
The mike is on a flexible boom that clips to my shoulder harness, much more
comfortable than than being clamped around my head or over my ears.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=467781#467781
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