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Author Topic: Graupner 700 speed controller  (Read 579 times)

Rixs

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Graupner 700 speed controller
« on: November 01, 2019, 10:55:22 AM »

I bout a second hand boat, a  riviera 80, it came with a graupner 700 speed motor, but nothing else, I bought a cheap speed controller off eBay, looked like it was big enough but I smoked it when I plugged it in. I was using a 3s lipo the esc was for lipo up to 3s. Plugged it in the esc made all the right sounds, then the prop spun extreemly fast and smoke from the esc.


What can I do? What speed controller should I use?
Do I need suppression on the motor?


HELP!
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chas

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Re: Graupner 700 speed controller
« Reply #1 on: November 01, 2019, 12:07:23 PM »

It's not just the voltage you have to look at, it's the current ( amps). The Chinese ESC s are infamous for their optimistic specifications, and you've just seen the result of that when yours burnt out.
  To get a suitable ESC, you need to know the maximum current the motor is likely to draw and there are different versions of the Graupner 700 that draw different amounts ( and different maximum voltages)  Have another look at the motor and tell us which version you have. I'm betting you'll need an Mtroniks Viper 50 amp ESC or similar.
  These are good but expensive so an alternative is to consider a swap of the motor to a brushless type with its own ESC. It won't save you money but you would get better performance, probably with a better run time.
Chas

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Rixs

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Re: Graupner 700 speed controller
« Reply #2 on: November 01, 2019, 02:33:08 PM »


Graupner 700 race no. 6318 9.6 v


cheers
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chas

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Re: Graupner 700 speed controller
« Reply #3 on: November 01, 2019, 03:03:12 PM »

Speed 700 RACE 9.6v 7.2-9.6v 19 000  3.3A 17.5A  90A
Those figures are lifted straight from Graupners site. As you can see, the maximum voltage is 9.6, your 11.1 is going to ruin the motor whatever ESC you use..
  My choice would be the Viper 50 amp ESC with a 30 amp fuse between the motor and the ESC, because the stall current of 90 amps is quite high.
  Make sure you don't use too large a prop, this a quite a revy motor.
  I still think brushless would be a better solution, especially as you have a 3 s lipo you can't use with this motor.
Other solutions are available.


Chas
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Rixs

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Re: Graupner 700 speed controller
« Reply #4 on: November 01, 2019, 03:48:42 PM »


A full change to a brushless motor is probably the easiest way, but not the cheapest, I recon I need somewhere around 100 sterling to get both, that's why I went for the brushed esc. the only brushless motor I have spare at the moment is a 15- 25v motor which I used on 5kg plane on 6Ss which will be too much for a little boat!


what size brushless do you think will do it, not for flying across the lake and breaking water speed records just a decent scale speed with a bit extra  :-))


I have some 2 s ~I can use these will be better?
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chas

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Re: Graupner 700 speed controller
« Reply #5 on: November 01, 2019, 05:19:47 PM »

This is a can of worms, we all have different ideas about the best motor, and how fast we want the model to go. As a starting point, I have a 40 inch asrl, I wanted it to run nicely above scale speed. My view is that a scale model going like a fast electric racer looks all wrong. Others will disagree with that. I've installed a Hobbyking 2826 10 1400 kv motor, cost about a tenner. With it I use a hobbyking 45 amp car esc  which costs about 20 quid. Running on 9.6 volts I usualy throttle back just a little to get the fast scale planing speed I want. I imagine that if these were installed in your 33 inch model on 3s lipo you would have pretty quick but not racing performance. It's not expensive stuff and works well.


Chas

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T888

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Re: Graupner 700 speed controller
« Reply #6 on: November 01, 2019, 05:25:50 PM »

Gents,
Iím running in my 1/12 scale RIB , with a 28mm KMB water jet unit, motor a speed 700 , 50 amp speed controller, 11.1 Lipo with a 30 amp fuse. Only had one fuse blow due to sucking in a stone , which jammed the impeller.
Iíve been running this set up for 11 months with no issues .




The ESC came from Howells Modes, Battery from Components Shop.
50A Marine Boat ESC Electric Speed Controller Waterproof
£27.99
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Regards Dave
In Build ..... USS Roosevelt (DDG-80) KM Graf Spee ,KM Sharnhost
HS Elli? In Refit HMS Cornwall T22.

RST

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Re: Graupner 700 speed controller
« Reply #7 on: November 01, 2019, 06:44:21 PM »

Just to say also from what you posted (no esc details) unless it wasn't rated for start-up current it shouldn't have blown from your description!? Make sure you report details of what you have and make sure you get a refund.


Also, there's allot of variants of Graupners motors so if you choose to stick with it, check the details and post up.
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chas

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Re: Graupner 700 speed controller
« Reply #8 on: November 01, 2019, 06:56:35 PM »

I have made some assumptions in replying, but I did mention that this motor is available in different versions, that includes a 12 volt one. I'm guessing that is why T888 is fine on 11.1 volts.


Rixs has already posted the motor details.


 Although not stated, I bet everyone reading this thread is betting on the  common 320 amp chinese esc so often discussed on here. Not much chance of a refund, but you never know.

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RST

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Re: Graupner 700 speed controller
« Reply #9 on: November 01, 2019, 07:07:26 PM »

pffffff.  Sorry chas (and Rixs), missed that post about the motor number on my phone before.  I'd still try and get my money back though.

I like Mtronics personally -but no experience with the bigger ESC's.  No sympathy with cheap chinese / ebay / imported stuff but I know folk are happy to use them or accept the odds -buy 3 and throw at least 1 away.

Rich
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T888

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Re: Graupner 700 speed controller
« Reply #10 on: November 01, 2019, 07:30:03 PM »

Like RST, Im a Mtronics fan, Iíve use them all the time, my RIB is the exception.


But as I said in my last this cheaper ESC seems ok , yes the speed 700 Iíve used is the 12v version.
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Regards Dave
In Build ..... USS Roosevelt (DDG-80) KM Graf Spee ,KM Sharnhost
HS Elli? In Refit HMS Cornwall T22.

Rixs

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Re: Graupner 700 speed controller
« Reply #11 on: November 02, 2019, 02:00:20 PM »


I found one on amazon, 791655682214 - no reviews, but is a 320a waterproof esc I suspect another Chinese esc by the time I have finished buying cheap esc I could have bought a decent one first time. I normally buy good quality stuff but my wife is close to doing a pearl harbour on my boat collection. I think I am up to 19 now 16 of them yachts....


I am expecting that this will last a few seconds like the last one, if it does then I am going brushless. aquastar 3974 with a 120 amp esc - at least I know this combo works.
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chas

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Re: Graupner 700 speed controller
« Reply #12 on: November 02, 2019, 04:06:13 PM »

Those things aren't what they appear. Some people use them successfully for low amp installations, but with your motor it's just a short duration smoke generator. Nearly instant failure.
Chas
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chas

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Re: Graupner 700 speed controller
« Reply #13 on: November 02, 2019, 04:18:33 PM »

I forgot to say that you might like to look on YouTube at model racing boats with that motor and lipo  choice. Superb full on racing performance, in an appropriate hull. In your model it would be..Ö....very interesting. I look forward to a video of the results. Keep us posted.
Chas



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Rixs

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Re: Graupner 700 speed controller
« Reply #14 on: November 02, 2019, 06:29:11 PM »

Yes probably too big a motor, but itís all in now with the 700 motor and a 2 s seemed to work no smoke from the esc.so will also take a 3s with me tomorrow.


One problem though the throttle self centres supposedly  to give fwd and rev, but I donít always get reverse, probably another duff esc.


If the weather is ok tomorrow I will try and get some footage....
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JimG

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Re: Graupner 700 speed controller
« Reply #15 on: November 02, 2019, 07:42:15 PM »

A reason for not always finding reverse is the esc having a brake function (intended for buggies.) You might need to go to reverse then neutral and reverse again before reverse kicks in. The first time the stick is lowered it acts to stop the motor.
Jim
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Rixs

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Re: Graupner 700 speed controller
« Reply #16 on: November 04, 2019, 11:14:00 AM »

So, it did work on 3s no smoke everything still working afterwards, however, the speed performance want not good, it was definitely lazy cruising, more canal narrow boat speed than a motor launch! Looks like I will need to go brushless.


Since the performance was very poor I didnít bother with the video.


I have 3 motors to choose from taken out of dead aeroplanes
BL 4030/10 - 18- 29 volts but it will run on 11.1
BL 2220/7 - 11.1 volts
Bl 2215/25  11.1 volts


Which one?


Or none of the above and get a new motor.?

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