Today's Message Index:
----------------------
1. 04:29 AM - Re: Over-voltage Circuit Trips (Fred Stucklen)
2. 07:54 AM - Re: solid wire in PGID terminals (Robert L. Nuckolls, III)
3. 07:56 AM - Re: Over-voltage Circuit Trips (Robert L. Nuckolls, III)
4. 09:22 AM - =?utf-8?B?QWx0ZXJuYXRvciBraWNraW5nIG9mZiBsaW5lLg==? (=?utf-8?B?YW1leWVyQG1pbC1hbWF4LmNvbQ==?=)
5. 10:17 AM - Re: Alternator kicking off line. (Robert L. Nuckolls, III)
6. 10:28 AM - grounding (bob noffs)
7. 02:35 PM - Hints for recycling furnace blowers . . . (Robert L. Nuckolls, III)
Message 1
INDEX | Back to Main INDEX |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Over-voltage Circuit Trips |
Jack,
Check for a loose connection in the field circuit, especially in the
alternator connector (if you have one). Any
Interruption in the field circuit current (after the regulator) will cause
an overvoltage condition when the
connection is reestablished. This is especially true for a slow responding
regulator... Engine heat will
sometimes cause the alternator connector contacts to become loose.
Also check for an intermittent regulator ground ..
If the regulator is internal to the alternator, check for an intermittent
engine ground back to the battery.
Fred Stucklen
RV-7A N924RV 750 Hrs (Flying
RV-6A N926RV 875 Hrs (Sold)
RV-6A N925RV 2008 Hrs (Sold)
Time:
12:16:39 PM PST US
From:
Jack Haviland <jgh2@charter.net>
Subject:
Re: Over-voltage Circuit Trips
On Jul 12, 2012, at 5:40 PM, Robert L. Nuckolls, III wrote:
>> Since my RV first flew about a year ago the over-voltage circuit
has
frequently tripped shortly after take off. Resetting the 5 amp
pull-able
circuit breaker once or twice generally prevents a re-occurence for
the
remainder of the flight but I need to determine the root cause and
correct it.
>
> Jack, I'm not ignoring you. Will have a response
> and some suggestions in the morning . . .
Thanks Bob. A short flight this morning demonstrated that replacing
the
suspect circuit breaker did not correct the situation. The main bus
was
at 12.6 volts prior to start and read a solid 14.2 volts during the
flight. The EIS (on the endurance bus) was displaying around 13.6
volts
but the breaker tripped twice during each of two climbs to the
pattern.
All connections and terminals in the field circuit appear to be
secure.
The aircraft instrumentation does not include a recording capability.
Suggestions will be greatly appreciated!
Jack
Message 2
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: solid wire in PGID terminals |
At 07:58 PM 7/13/2012, you wrote:
>
>Turns out I'm misinformed again. The pgid terminal specs in the
>Digikey specify SOLID OR STRANDED wire.
>
>The only possible defense of my error I can find is that some larger
>crimp on lugs (starting at #8 wire) specify that they are for
>stranded wire, although they don't specifically prohibit solid wire.
>
>Thanks again for helping me get things right.
Looking though the AMP literature, they DO make
a distinction between terminal types for solid
vs. stranded wire.
http://www.te.com/catalog/GeneralInfo/sbli04a.gif
We can see that AMP offers a 'specialized' product
tailored to single-strand wire. Adding a degree
of 'roughness' to the inside surface of the wire
grip increases tensile strength of the joint (of
negligible concern in aircraft wiring) and an
increase in electrical contact area. This last
benefit is also a tiny percentage increase. Since
we don't even begin to load wires in airplanes
like they do in ground based vehicles, this too
would be a no-big-deal benefit. This is not intended
to detract from the engineering that goes into
AMP products . . . at the same time, I deduce that
it's not significant to the task of wiring a diode
to the outside of a contactor.
Bob . . .
Message 3
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Over-voltage Circuit Trips |
P.S. forgot to mention that each revolution of the calibration
pot on my modules moves the setpoint about 0.5 volts. So if
you're getting nuisance trips with a bus voltage that is running
in normal ranges, you can try one half turn of counter-clockwise
adjustment and see if the trips stop.
Bob . . .
Message 4
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | =?utf-8?B?QWx0ZXJuYXRvciBraWNraW5nIG9mZiBsaW5lLg==? |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=
Message 5
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Alternator kicking off line. |
At 11:20 AM 7/14/2012, you wrote:
>I am having an issue where when I key the Mic on my Garmin430 comm (
>my only comm radio), my alternator kicks off line. This doesn't
>happen on the ground shortly after starting, buy when airborne,
>etc... It now occurs almost 100% of the time. This happened for a
>while intermittently, but is now very frequent. I have a Cessna
>style split switch and need to turn off and back on the alternator
>side to restore charging to the system. Thoughts? Troubleshooting
>steps? ID10T errors?
>
>Happy Flyin'!
>Andy
This has the smell of an RF interference issue
between ov sense circuits and your comm transmitter.
What kind of airplane? What kind of regulator/ov
protection system? Where is your antenna located?
Have you checked the SWR on the antenna to be
sure of feed line integrity?
Bob . . .
Message 6
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
hi all, thanks to all who responded for all the info, ideas. sooooooooo
here is my plan
i will use a new 55 gal drum with a 12 volt pump and conductive hose to a
metal end. pump will be grounded to metal rod in ground.
i picked up from all the info that electrical connection to hose end and
airplane tank before fueling is the key to prevent sparks so i will either
connect pump to exhaust pipes or tank rim to hose end before filling.
i will pick up a new oil drum for $20 next weekand start to put this
together.
thanks again, bob noffs
Message 7
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Hints for recycling furnace blowers . . . |
For years, I've used salvaged the guts of furnaces
to fabricate utility blowers for carpet drying,
workspace comfort, paint drying, etc. Dr.
Dee occasionally uses an energetic blower outdoors
when gardening in hot, low-wind weather.
These blowers are compact (motor mounts inside
the blower wheel) and often include some variable
speed options. They can be had for very little
from HVAC companies that change out old furnace
and a/c units. I just picked one up at a garage
sale for $20 where the owner had already mounted
it to a base and fitted with a carrying handle
and line cord.
Most DIY conversions I've seen in the wild do
not account for the fact that these blowers
are designed to push LOTS of air through a maze
of ducts. I.e., they are intended to do more
WORK than just move xx cubic feet of air per
minute. There is back-pressure of the duct work
to consider.
Referring to an exemplar speed vs. torque and
current curve . . .
[]
We can see that there's a 'hump' in motor's torque
curve. We also see that rated operating characteristics
for the motor are on the right-side of that hump.
This means that for the motor to start up and
accelerate past the hump, the load on the
motor MUST be less than the 'break down'
torque else the thing won't make it up the
hump to it's operating point.
I knew that the blower I just bought was
exceedingly crippled in performance . . . it's
outlet port was wide open. Sure 'nuf. Got it
home, plugged it in . . . it did indeed move
some air. The snap-on ammeter read 4.5 amps.
But operated completely open loop, it gulped
in and tried to accelerate too much air.
I took a scrap of plywood and blocked off
about 1/3 of the outlet. The motor accelerated
up over the hump, rpm rose dramatically and it
really began to move some air!
I've added a permanent baffle adjusted so that
the motor draws about 3.5 amps. That's 'cause
I'm too lazy to take it apart and see if the
motor frame is marked with rated load current. If
I knew what the rated current was, I'd adjust
the baffle to achieve that current. In any case,
it now draws 1 amp less than when I bought it
and moves a great deal more air.
This is something to remember about induction motor
characteristics . . . they must be loaded well
down the right side of the 'hump'.
If any of you have ever used an induction motor
lawn mower, you may have experienced what one might
call 'motor stall' when pushing too rapidly into
tall weeds . . . the speed is loaded down to where
the motor tumbles down the front side of the hump.
You have to pull back and let it recover.
For you techno-nerds, max torque (or breakdown torque)
from an induction motor occurs at a 'slip frequency'
in the squirrel cage where inductive reactance is
equal to the DC resistance of the cage conductors.
It's 105 out there today . . . added air motion
in the shop will be welcome.
Bob . . .
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|