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500ma contact rating for a pressure switch will
never work on a solenoid operated hydraulic pump.
As Bill just indicated, 4 amps to the solenoid that
runs the pump is typical.
The only way that 500ma pressure switch can work is
to use a relay in between the switch and the solenoid.
. . . . or just use a relay on the original (new)
pressure switch and it's contacts will last a lot longer without the radio noise
problem.
Wolfgang
----- Original Message -----
Sent: Tuesday, February 08, 2011 2:58
PM
Subject: LNC2 Hydraulic Landing Gear
Pressure Switch Wear Issues
Great idea, but my relay coils (vintage 1990 360) require
4 amps, tested today, perhaps 5 amps with engine running. We would need
a power transistor to supply the required current.
Anybody know
of a similar PS with a 5A or greater rating?
Regards,
Bill Hannahan
--- On Mon,
2/7/11, Bruce <BGray@glasair.org>
wrote:
From:
Bruce <BGray@glasair.org>
Subject: [LML] Re: LNC2 Hydraulic
Landing Gear Pressure Switch Wear Issues
To:
lml@lancaironline.net
Date: Monday, February 7, 2011, 8:18
PM
I would think
that ½ amp at 14v should be enough.
-----Original
Message-----
From:
Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of
Sky2high@aol.com
Sent: Monday, February 07, 2011
2:53 PM
To:
lml@lancaironline.net
Subject: [LML] Re: LNC2 Hydraulic
Landing Gear Pressure Switch Wear Issues
Their specs
look great. Is the 500 mA current limitation adequate for
operating clunky 12 VDC intermittent relays (the pump power
switch relays)?
In a message
dated 2/7/2011 11:32:18 A.M. Central Standard Time, BGray@glasair.org
writes:
Several of
our guys (including me) have junked our mechanical pressure switches
and moved to solid state adjustable switches.
http://www.automationdirect.com/adc/Search/Search?searchquery=PSD25-OP-5800H&cmd=Search&fctype=adc.falcon.search.SearchFormCtrl&TxnNumber=-1
-----Original
Message-----
From:
Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Don
Gordon
Sent:
Monday, February 07, 2011 7:45 AM
To:
lml@lancaironline.net
Subject: [LML] LNC2 Hydraulic
Landing Gear Pressure Switch Wear Issues
I have
recently replaced both my high pressure and low pressure switches in
the hydraulic system for the landing gear. These switches
began to have trouble providing a positive and discrete on/off event
when the hydraulic pressure reached the prescribed limits. I
began to hear strange crackling and static noises in my headset just
prior to the hydraulic pump running (though it would just run for a
fraction of a second to re-pressurize). These strange sounds
in my headset began to occur longer and longer prior to the pump
tripping on. I also began to notice some other odd electrical
issues with the aircraft. Finally, I began to suspect these
switches were faulty are replaced both of them. The problem
went away and so did my electrical issues I
experienced.
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