Re: "Coil suppression can reduce relay life"


Bruce Hughes
 


I suggest you Look in the B & C catalog for the S811-1 and S701-1

This is NOT a recommendation; just telling you how my
Longeze is powered.

I also have  B & C starter, alternator, linear controller,
20 position fuse holder, fuses (that indicate when
blown so easy to find), and a grounding block.

I had a lot of electrical system trouble before I started
buying from B & C.

Remember this is NOT a recommendation.

Bruce Hughes



Bruce Hughes



----- Original Message -----
From: jack711cz eznoselift@... [canard-aviators]
To: Canard Aviators <canard-aviators@...>
Sent: Sat, 11 May 2019 15:55:08 -0400 (EDT)
Subject: Re: [c-a] "Coil suppression can reduce relay life"







Master solenoid failure is very common when using the traditional circuit that feeds the starter solenoid (200amp intermittent ratting) current through the master solenoid (30 amp continuous rattng). This subject has been discussed on the Cozy forum. 

Regards

Jack Wilhelmson

On Sat, May 11, 2019 at 1:01 PM Bill Allen billallensworld@... [canard-aviators] <canard-aviators@...> wrote:
 


Having had master contractors fail on me in certified aircraft, I am seriously contemplating replacing an electromechanical (traditional master solenoid) with a simple mechanical one, which, as a bonus, doesn’t consume power ( about 1.5a)

Flaming River do a range of these devices;
 and, for Education and Recreation, could provide a simpler solution in an experimental aircraft.

Bill Allen

On Sat, 11 May 2019 at 18:40, Mike Satchell mike.satch@... [canard-aviators] <canard-aviators@...> wrote:
 


Jack,


The starter solenoid is my highest concern regarding this topic.  
It's not uncommon for them to fail and sometimes, it is a
catastrophic event.   An increased breaking force (faster drop
out) should decrease the likelihood of welded contacts.


  

Regards,

Mike Satchell







On 5/11/2019 10:42 AM, jack711cz eznoselift@...
[canard-aviators] wrote:






 
MIke:

Your missing the point here. The point is relay
reliability, not drop out time.

Regards

Jack Wilhelmson

On Sat, May 11, 2019 at
10:39 AM Mike Satchell mike.satch@...
[canard-aviators] <canard-aviators@...>
wrote:
 


Same
resistive load, same type of relay, same
number of cycles.

Long versus short decay rates.








I posted the original note to point out
something I thought was unusual and noteworthy
since most of us are familiar with the
benefits of suppression diodes, but weren't
aware of the unintended consequences.


Regards,

Mike Satchell



On 5/11/2019 8:59 AM, jack711cz eznoselift@...
[canard-aviators] wrote:
 
This data shows that the
diode slows the coil drop out but there is
no data about the failure rate or the
number of actuations before failure of the
relay. This kind of data is usually in the
30,000 to 50,000 (same as UL testing of
switches).

BS is often supported by non relevant
data.

Regards

Jack Wilhelmson

On Sat,
May 11, 2019 at 9:19 AM Mike Satchell mike.satch@...
[canard-aviators] <canard-aviators@yahoogroups...com>
wrote:
 


Apparently
there is more fact than
opinion as it is a measurable
phenomena.

http://www.crydom..com/en/tech/newsletters/solid%20statements%20-%20coil%20suppression%20&%20dc%20output%20ssrs.pdf




This from Wikipedia
https://en.wikipedia.org/wiki/Flyback_diode


"When the inductive load is a
relay, the flyback diode can
noticeably delay the release
of the relay by keeping the
coil current flowing longer. "



On 5/11/2019 8:08 AM,
jack711cz eznoselift@...
[canard-aviators] wrote:
 
This "so
called technical"
articular is nothing more
than one engineers
opinion. No data on
testing to actually show
how much a diode across a
relay coil, to stop
negative voltage kick
back, shortens the relay
life. I have been using
relays with diode kickback
protection for forty
years. They become very
important when the relay
coil driver circuits are
solid state electronics. I
also have my own opinion
and many years of
experience and it does not
agree.

Regards

Jack Wilhelmson

On
Fri, May 10, 2019 at
8:21 AM skyeyecorp@...
[canard-aviators] <canard-aviators@yahoogroups..com>
wrote:
 
Very
interesting
little article
Mike. A
worthwhile
refinement to
established
procedure to
keep in mind
for the next
time I wire a
master/starter
contactor.
--Jose


On Thu, May
9, 2019, at
9:40 PM, Mike
Satchell mike.satch@...
[canard-aviators]
wrote:
 
Here
is an
interesting
application
note
suggesting the
use of zener
diodes in
series with
the
suppression
diodes
particularly
when solid
state switches
are used.

Maybe the lone
diodes across
the master and
starter relays
coils are
great for EMF
suppression
but less than
optimal for
breaking the
contacts open.

...









--







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