Mailing List lml@lancaironline.net Message #2494
From: John Cooper <snopercod@citcom.net>
Subject: Bosch Hydraulic Relays
Date: Wed, 02 Jun 1999 20:11:42 -0400
To: <lancair.list@olsusa.com>
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<<He also said they were solid state and therefore, didn't need diodes across
them for arc suppression. Is that true?>>

No. With all due respects to Don who is one hellova pilot and my friend,
these relays do NOT contain any semiconductor devices. They DO have
"pre-contacts" which limit arcing when switching inductive loads in order
to extend contact life.

I am glad that Don and Neico have finally "discovered" these relays since I
first sent them samples over seven years ago...grumble...grumble...

...writing this from the "kitchen table" of my travel trailer in the
foothills of the Great Smokey Mountains of NC...

<JC>


[As mentioned previously here, don't forget that these relays are
a bit different mechanically than the starter relays which are provided
with the kits.  The Ford relays include a 'signal' contact which is used
to send voltage to the transit light... these relays do not have that
contact.  The solution is a simple one, however, and provides both
the isolation between the two relay coils and contact arc suppression at
the same time.  Using a full-wave bridge rectifier is the answer...  run a wire from the + side of each relay coil to each of the AC terminals on
the rectifier.  Connect the + side of the transit light to the + side of
the rectifier and the - side of the rectifier to ground.  I'm using Mouser part # 625-GBPC35005 (35A, 50V) as it attaches with a #8 screw
through its center and uses 4- .250x.032 Faston terminals for its
electrical connections.       <Marv>     ]



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