Model Boat Mayhem - Forum

Technical, Techniques, Hints, and Tips => BRUSHLESS Motors and Speed Controllers => Topic started by: tobyker on July 16, 2009, 10:27:12 PM

Title: cutting out motor
Post by: tobyker on July 16, 2009, 10:27:12 PM
I'm resurrecting the plywood pre-dreadnought battleship while I think about the jet boat (this is the boat made from odds and ends over the past 15 years or so). It is not so much "stand-off" as Impressionist. I see that simple outrunner/ESC flight packages come very cheap nowadays. I'm thinking of getting a couple for the battleship, and using one channel to work switches to reverse the motors by swapping two of the motor wires over. I'll use a y-lead from the Rx to the ESCs. In order to add manoeuverability, I'm wondering about interrupting the third wire on full rudder lock to cut out the motor on the inside of the turn. However, If I break the wire between an ESC (that is getting a full speed instruction from the Rx) and the motor, will this fry the ESC?
Title: Re: cutting out motor
Post by: stallspeed on July 16, 2009, 10:39:14 PM
Why not post what budget units you found?
Maybe somone will locate an equivalent reversing  brushless esc.
Title: Re: cutting out motor
Post by: tobyker on July 16, 2009, 11:37:16 PM
The motor/ESC are as below - 13.99, from BRC hobbies.
BRC CF2822 (125W) 1200Kv Brushless Motor & WASP 12A ESC Combo Deal brc233

Title: Re: cutting out motor
Post by: stallspeed on July 17, 2009, 12:17:30 AM
Quote
Type: Wasp 12A
* Weight: 7g
* Size: 22 x 18 x 5mm
* Constant Current: 12A
* Max Current: 15A (for ten seconds) <<<
* FET: 6
* BEC: Yes 2A
* PWM: 8 KHz
* Input: 2-3S Li-Po, or 6-10 Ni-xx
* Supplied with instructions

Quote
this an excellent BRUSHLESS ESC for INDOOR and PARKFLYER models

I think the power profile of a heli or plane esc would differ from a boat esc.Perhaps someone with both boat and parkflyer experience has something to say.

I'm sure technobots, giantcod.co.uk or r2hobbies.com have some reversible brushless escs by now.I mean ones that are centre-off.Don't confuse with aero escs which allow you to "servo reverse" the esc after the motor to esc cables are already soldered.


Title: Re: cutting out motor
Post by: red181 on July 19, 2009, 11:00:51 PM
I am still trying to get a defined answer on is centre stick off, and real reverse, but if you search fleabay for hobbywing seaking esc, these are water cooled, listed as specific brushless boat esc's, and state "forward, and forward/reverse. There are chices for the amps, I think 60amps is the smallest though, but you could always use it for another project at a later date.

If anyone has tried these, I would be interested in the feedback,

Thanks
Title: Re: cutting out motor
Post by: stallspeed on July 19, 2009, 11:56:01 PM
Is it even worth switching the motor wires now?
Turborix AE 30A Bi-directional Brushless Motor ESC Electronic Speed Controller at 24 ?  (http://www.r2hobbies.com/proddetail.php?prod=rcps81707_30)
quote from supplier: For R/C cars and Boat applications (with forward and reverse motion control function)

I think there is mention of the seaking on Mayhem

What about low speed control on brushless systems?
Anyone?
Title: Re: cutting out motor
Post by: tobyker on July 20, 2009, 01:27:42 AM
Yes looks good but still 24 per ESC. Still the technical question  - will the ESC fry if the motor is disconnected while the ESC is still pumping out its pulses?
This model is built from offcuts and rubbish and I don't want to put over 50 worth of kit in it.