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Author Topic: Reversing brushless esc  (Read 3267 times)

6705russell

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Reversing brushless esc
« on: March 21, 2012, 11:01:13 AM »

I have just bought two Turnigy speed controllers which are ideally suited for brushless motors coupled with gear boxes, the ramp-up can be set to a very low ratio which is ideal for large scale boats, only snag is they dont do a reversible model, what i intend to do is connect through a double pole/double throw relay and reverse polarity between two of the motor wires  at the flick of a switch, has anyone used this method before?

Thanks

Russ
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roycv

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Re: Reversing brushless esc
« Reply #1 on: March 21, 2012, 11:05:00 AM »

Hi, all you need to do is to switch any 2 leads (of the three) over of the brushless motor to reverse it.
regards Roy
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6705russell

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Re: Reversing brushless esc
« Reply #2 on: March 21, 2012, 11:12:03 AM »

Hi Roy

Yes I Know that, but it needs doing remotely when the boat is out on the water..

Thanks

Russ
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essex2visuvesi

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Re: Reversing brushless esc
« Reply #3 on: March 21, 2012, 11:25:31 AM »

no reason why it shouldn't work as long as you can find a switch to handle the current draw
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dodgy geezer

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Re: Reversing brushless esc
« Reply #4 on: March 21, 2012, 11:30:19 AM »

I have just bought two Turnigy speed controllers which are ideally suited for brushless motors coupled with gear boxes, the ramp-up can be set to a very low ratio which is ideal for large scale boats, only snag is they dont do a reversible model, what i intend to do is connect through a double pole/double throw relay and reverse polarity between two of the motor wires  at the flick of a switch, has anyone used this method before?



That will do it. Possible snags:

1 - you will be able to get full speed in reverse as well as full speed in forward. Depending on your model, this might not be something you want...

2 - a simple design of this kind might allow you to throw the motor directly from full-forward into full-reverse. Even if this were just to happen accidentally, it's probably not the sort of thing you want to have happen, and it might be worth designing some delay or locking mechanism in...

3 - I wonder what might happen to an esc if two wires were changed while there was power going down them. Perhaps ACTIONman can help us with this one...
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andrewh

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Re: Reversing brushless esc
« Reply #5 on: March 21, 2012, 12:48:08 PM »

Hi, russ

Yes, this is how I get reverse on lilght brushless boats using flight ESCs

I wrote about it in the Brushless basics spiel, and did photos.  In fact the circuitry is identical to what you use to reverse a brushed motor

I did speak with FLJ about the concept, as I was then (am still) sure that one of his clever widgets would make this easier but finished with 2 microswitches and a mini-servo

all that DG says is true, and all that FLJ says about microswitches - but go for it

andrew
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6705russell

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Re: Reversing brushless esc
« Reply #6 on: March 21, 2012, 01:32:59 PM »

Thanks chaps

I have just nipped round to Maplins and picked up a relay, I will see how it goes later...

Russ
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Mad_Mike

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Re: Reversing brushless esc
« Reply #7 on: March 21, 2012, 03:17:36 PM »

which turnigy brushless esc did you buy?

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roycv

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Re: Reversing brushless esc
« Reply #8 on: March 30, 2012, 11:30:16 PM »

Hi, I did have a plan to use a forward only brushless esc by having a toggled electronic switch on what would have been reverse.  Using this to call a dpdt relay to reverse the motor.  Ok for slow models but I was not so sure with a planing launch and ended up with a Turnigy F/R esc.  This took some setting up but my one loses its' sense of working after a while and I have to connect it to a 6 ch set that gets it going again.

I could not get it to work with Hitec on 40 Mhtz.
Gone back to brushed motors now.

I was enthusiastic about brushless but this has waned, but have enough of the other kind to see me out.
regards Roy
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john44

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Re: Reversing brushless esc
« Reply #9 on: March 31, 2012, 05:40:09 PM »

Hi Russ, Peter Kelly used a change over relay and I am not sure if he still does on his very fast brushless Sea Queen.
his email and phone number are in the PMBC members list, I am sure he will be able to help you.

john
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6705russell

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Re: Reversing brushless esc
« Reply #10 on: March 31, 2012, 05:48:41 PM »

I have sorted now John myself, I used two  double pole/double throw relays to change polarity on two of the motor cables....

Cheers

Russ
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red181

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Re: Reversing brushless esc
« Reply #11 on: April 13, 2012, 12:39:08 AM »

turnigy do produce reversing esc's for brushless use, I have a number of them, would it not be easier to just use them instead of trying to rewire a forward only esc?
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CF-FZG

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Re: Reversing brushless esc
« Reply #12 on: April 13, 2012, 07:47:38 AM »

turnigy do produce reversing esc's for brushless use, I have a number of them, would it not be easier to just use them instead of trying to rewire a forward only esc?

Please read the opening post again, if one of them suits that application please tell us which one :-))

Thanks,
Mark
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dodgy geezer

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Re: Reversing brushless esc
« Reply #13 on: April 13, 2012, 10:09:47 AM »

This thread in the Batteries section has some relevant messages on reversing brushless motors by changeover switching:

http://www.modelboatmayhem.co.uk/forum/index.php?topic=36390.0


Here is a proposed switch:



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red181

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Re: Reversing brushless esc
« Reply #14 on: April 24, 2012, 11:24:39 PM »

sorry for late response, dont come on here much these days, I have turnigy marine 60amp brushless esc's, the set up is as bit fiddly first time, listening to the beeps in sequence to set it, but once done they hold the settings.

you have to programme if you want forward/reverse, or just forward, the default is forward only, and you have to set up what batts you use, and the cut off voltage, I use lipo, which is a max of 6 cells on the 60amp unit. The instructions show a range from 25a to 180a, all  seems to have a built in bec.

I will be shortly running two in a twin brushless setup, but up to now have only run one at a time. They are watercooled, are reputed to be waterproof, but I doubt that very much!

Timing can be set, I dont rreally understand that so ,left at teh default, in my 24" Aerokits fireboat I get a very smooth slow start up, so no problem with nice slow scale speeds, its a double click action to achieve reverse, (First click is like a brake, )which again is fully proportional
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