Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: Earthing the negative poles  (Read 651 times)

Southern Sailor

  • Southern Sailor
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 140
  • Location: Cape Town, South Africa
Earthing the negative poles
« on: December 05, 2013, 02:19:17 PM »

Good day all.  In a recent article in MBM the suggestion was made (in place of installing a capacitor from each terminal to the motor casing) to connect all battery negative terminals to a suitable earth - a stern tube was suggested.  I am using an old - at least 10 years - car fan motor with independent Electonize ESC on each. Each motor has its own 12V 7AHr gel cell.  In terms of the article the negative terminals can be connected to the same stern tube.  Any problems with this?  {:-{  Happy sailing.  Brian
Logged

nemesis

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 467
  • Location: North Shields. Northumberland
Re: Earthing the negative poles
« Reply #1 on: December 05, 2013, 02:29:02 PM »

Hi, take a wire from the motor case to the prop shaft outer. In big boat practice you often find a large earthing plate fitted on the bottom of the hull, I believe they were on wooden built boats. Nemesis
Logged

malcolmfrary

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,551
  • Location: Blackpool, Lancs, UK
Re: Earthing the negative poles
« Reply #2 on: December 05, 2013, 06:49:41 PM »

The suggestion was made as an optional extra measure if the capacitors alone do not work, along with the use of ferrite rings and twisting the (insulated) motor leads together.  Generally I have found that if the capacitor treatment doesn't work then the motor needs some close attention.  If new brushes and/or cleaning and/or skimming the com are either ineffective or not possible, the answer is to "mend it with a new one".  Some motors are simply proof against any method of suppression.
Logged
"With the right tool, you can break anything" - Garfield

Southern Sailor

  • Southern Sailor
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 140
  • Location: Cape Town, South Africa
Re: Earthing the negative poles
« Reply #3 on: December 05, 2013, 07:29:26 PM »

Hi Guys. Thank you for your responses.  MMM say to not use any suppression.  The motors are not high revving and I will try them with no suppression.  It is just that before I put the deck on, I want to do all the necessary - easier before the deck goes on. The next move is to re-assemble the insides and do the sea trials; That should be a good indicator of any problems in this regard. I have left a gap in the paint of the port stern tube which will be a suitable earthing plate.  Then the deck.    Happy sailing. Brian
Logged
Pages: [1]   Go Up