Model Boat Mayhem - Forum

Please login or register.

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

Author Topic: brushless outrunner faster in reverse?  (Read 427 times)

shadysadie

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 76
brushless outrunner faster in reverse?
« on: October 24, 2018, 08:02:29 PM »

Hi folks. I'm gradually converting my sports boat "fleet" to brushless power and have so far been successful thanks to the invaluable assistance of this forum. I still have a lot to learn though as I found out today whilst bench-running a Turnigy L5055C 700KV which I have just installed in a boat. I'm using a Hobbyking 100A car ESC and 4S lipo, Hobbyking programme card to set things up and the motor runs very smoothly and quietly - success thought I. Wrong! The motor runs much faster in reverse than it does in forward so I swapped over the two outer leads from ESC to motor thinking that this would surely cure the problem. It didn't! Obviously, there must be a simple solution to this problem but I just can't understand it so, kind people, please put me out of my misery.


Regards, David.
Logged

tsenecal

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 310
  • Location: Arvada, Colorado, USA
Re: brushless outrunner faster in reverse?
« Reply #1 on: October 24, 2018, 08:26:32 PM »

you were half right....


It is obvious (to me) that what you are doing is running the ESC in reverse.  Tons of car and boat ESCs have this kind of setup:  forward is 100%, reverse is either 50% or 25%...  you need to reverse the direction of your throttle input on your radio, AND swap 2 of the 3 leads between the ESC and the motor.
Logged

malcolmfrary

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,405
  • Location: Blackpool, Lancs, UK
Re: brushless outrunner faster in reverse?
« Reply #2 on: October 25, 2018, 10:02:08 AM »

Nearly all manufacturers use the "standard" that a control pulse for neutral is 1.5mS long, forward up to 2mS, reverse down to 1mS.  Futaba like to be within limits, but a bit different.  In analog radio days, they used something like 1.25mS as neutral, and the forward/reverse logic was reversed.  This has very successfully created confusion for over a quarter of a century, and will no doubt continue to do so.  If any odd item in the chain is either actually Futaba, or conforming to Futaba's way of doing things, a work-round is needed.
As tsenecal says, you will need to set your transmitter channel so that the ESC gives full power to a forward stick mvement, then tweak the wires to the motor so that it spins in the right direction.
Logged
"Trying is the first step towards failure" - Homer (Simpson)

shadysadie

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 76
Re: brushless outrunner faster in reverse?
« Reply #3 on: October 25, 2018, 10:04:26 AM »

Many thanks tsenecal - another lesson learned and motor now running correctly.
Logged

shadysadie

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 76
Re: brushless outrunner faster in reverse?
« Reply #4 on: October 25, 2018, 10:08:51 AM »

And thanks malcolmfrary, all is now well and the learning curve is rising.
Logged

tsenecal

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 310
  • Location: Arvada, Colorado, USA
Re: brushless outrunner faster in reverse?
« Reply #5 on: October 25, 2018, 05:26:22 PM »

Many thanks tsenecal - another lesson learned and motor now running correctly.


happy to hear everything is working as expected.    :-))
Logged
Pages: [1]   Go Up