[AT] Why Ground a Generator

[Mary S Peak]

 As a female here I wouldn't want to sound dumb but when I use the
generator in my motorhome do I have to go out and put in a ground.
Mary.
PS
Boy I got back from visiting my sister in Coeur d'Alene and found that
some of you are real nasty to an old lady, some even accued me of not
being who I am. Well for that part they are correct I am not using my
real name so as to protect me from cyber attacks.

  ----- Original Message -----
  From: "Dudley Rupert"
  To: "Antique tractor email discussion group"
  Subject: [AT] Why Ground a Generator
  Date: Sat, 15 Dec 2007 00:57:08 -0800


  Maybe we can get a good argument going on generator grounding (but
  treat
  this as a wind chill free zone) -

  Dudley
  Snohomish, Washington

  I would think that grounding the frame of a generator that has a drop
  cord
  or two plugged into it, as well as grounding one side of its' output,
  would
  ensure that IF a short ever developed between either of the output
  terminals
  and the frame of the generator then a potential difference
  would/could not
  be created between the generator frame and the
  ground/concrete/grass/etc
  that it's sitting on. In other words, the innocent bystander would
  not get
  shocked if he touched the generator and the chances of arcing between
  the
  generator and the ground would be lessened. Note: I wonder, however,
  how
  often the generator is ever grounded in this case.

  BTW - This is the same grounding design as in the old steel power
  tools that
  had the 3-prong plug. The third prong, the grounding prong, connected
  the
  steel case of the power tool back through the ground wire to the
  ground bar
  in the service panel. The neutral wire (white wire) was also
  connected to
  the ground bar. The ground bar, of course, is connected to a ground
  rod and
  probably the copper/steel water pipes as well. I think good grounding
  of a
  generator with drop cords would/should. emulate the typical/good
  service
  panel ground design.
  When it comes to a generator that is connected to the service panel I
  don't
  know. I would think, however, that if the generator neutral is
  connected to
  the frame of the generator (I have no idea on this ... would like to
  hear
  from someone who does) then I think one could argue that the service
  panel
  ground would ensure that the frame of the generator is kept at ground
  potential and thus there would be no need to have a separate
  generator
  ground. However, I don't know what having one could hurt. If the
  generator
  neutral were not connected to the frame of the generator then it
  would seem
  that providing a ground for the generator would give the safety
  benefits
  described above.
  WOILF (Way Out In Left Field) - Another case could be made for good
  grounding of the power source but I am not sure how really applicable
  it is
  to the generator in the home environment (I don't think any at all).
  But -
  not that any old iron lover should care - in the avionics world it is
  big.
  A typical avionics unit, say a Flight Control Computer (Autopilot),
  communicates (both inputting and outputting data) with literally
  dozens of
  other units. Protocols (i.e., ARINC specs) have been established to
  govern
  the precise transmission and reception of this data. For example, say
  the
  Flaps Control Unit uses a logic discrete to output to other units if
  the
  flaps are properly configured for takeoff. So, let's say the Flaps
  Control
  Unit does determine that the state of this discrete is True. In this
  case
  the protocol says it should output a DC voltage of 3.5 or less. The
  protocol also says that any unit inputting this discrete should
  consider it
  True if it sees a DC voltage of 4.2 or less; otherwise consider it
  False.
  This communication requires not only good grounding of each unit
  involved
  but good grounding to a common source; that is, to the frame of the
  airplane. Otherwise the design used in many units permits the ground
  to
  "float" to an undetermined state. Say, for example, the sending unit
  is not
  grounded, or not grounded well, to the frame of the airplane but that
  the
  receiving units are. Then it is a real possibility that the sending
  unit
  could be outputting, for example, say 2 volts with respect to its'
  ground
  (to indicate a True) but, if its' ground is at say +5 volts with
  respect to
  the frame of the airplane, then the receiving units will see this as
  a +7
  volt input and interrupt it as False. OK, way off the subject of
  generator
  grounding -


  _______________________________________________
  AT mailing list
  http://www.antique-tractor.com/mailman/listinfo/at

-- 
10 Great Gift Ideas- Take a Look!
http://mail.shopping.com/?linkin_id=8033174