[Amps] Dielectric grease for roller inductors?

[Jim Thomson]

##  Got an  email from  Roger,  K8RI..  re  dielectric  grease.
It  appears  that  W8JI  didnt  quite  get  his  story  correct.

Silicone grease does not not decompose into Silicon Carbide, It 
decomposes into Silicon Dioxide + Hydrogen and/or Chlorine. There is no 
Carbon in the grease.

##     JI  did  not  use conducto  lube  either.   Conducto  lube  is  75%  pure  silver..and  25%  castor  oil.
Used  in  industry +  power  companies  on  sliding  silver  plated surfaces.  Transfer  switches  typ  use  several
silver  plated  fingers  in  parallel..per  phase. Also  used  on  spdt silver plated  knife  switches,  cut  outs, 
and  fuse  holders.   Each  particle  of  silver  in  conducto  lube  is  only  3-4  microns.  

##  I  agree  with  W8ZR  re  the  use  of  dielectric grease  on  coax  connectors.  It  works  good  on
both the  threads  and also the  center  pin,  but  only  a very  tiny  bit  is  applied,  real  thin  layer.
I  have  not  tried  conducto  lube  on  coax  pins...yet.  I  believe  it  would  work....  but  only  if  used 
sparingly.   I  would  only  use  dielectric  grease  on threads  of  coax  connectors.  I  use  7-16  Dins..
and  they  can  be  torqued  to   5  x   the   tq  used  on   SO-239  and  type  N   connectors. 

##  I  would  not  use noalox,  penetrox  on  anything  but  aluminum  to  aluminum  surfaces,  like  yagi
eles.  Both  products  are  just  ground  up zinc..in  grease. 

##  copper  kote  is  ground  up  copper  powder..in  grease....  used  only  on  cu  to  cu  surfaces,  like
bolted buss  bars. 

##  dielectric  grease is a total dead  loss  if  used  on  NC  contacts  of  open  frame  mech  relays,  JI
mentioned  that  on  qrz /  qth.com.   He  is  correct.   Typ  not  enough  spring  pressure.
I  would  not use  dielectric  grease  on  contactors..esp  if  u  are  slamming a big  load  on. 

##  I  did  notice  that  on  several  of  my brand new  Deltrol..and  also  P+B  DPST..and  also  DPDT  30A
relays,  the  contact  resistance was  really  high....  and  ditto  with  poles  1+3  of  my 65A   3  pole  contactors.

## I  tried  using a deltrol  /  P+B  30A  DPDT  relay  for a bypass  circuit in a hb  ant  tuner.  coax  to  coax  type.
It  would  int  go  open  on  RX....  with  tuner  switched  to  bypass.    My  fix  was to  apply  some  cool  amp
silver plating  compound to the contacts,  problems  solved,  no  more  int  RX. 

##  The  only  other  fix  was to  use a pair  of  rf  chokes, and apply  DC bias  to  NC  contacts.  Another
option  is to  use  ceramic  vac  relays.   For  hb  remote  switch  boxes,  I  use  gigavac  G2  relays..zero
issues  so  far.  

##  I  will  report  back,  when  I  have  finished   testing.

Jim   VE7RF






From: Kim Elmore 
Sent: Thursday, January 2, 2020 6:29 PM
To: Tom Hellem 
Cc: MU 4CX250B ; Jim Thomson ; amps at contesting.com 
Subject: Re: [Amps] Dielectric grease for roller inductors?

See https://www.w8ji.com/dielectric_grease_vs_conductive_grease.htm for the full treatise. Bottom line is the“conductive” grease refers to its thermal, not electrical, characteristics.  

Kim N5OO