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[Nige52]

What it means when an ESC is described as "Suitable for motors down to 20 turns" or "15 turns" or whatever? Such as the Mtroniks 15a Marine for example. I don't really know what this means, is a motor with more turns better than a motor with fewer? Why can't an esc handle more, or less turns?

Electronic dumbo
Nige 

[Shipmate60]

Nige.
This is from the Car and Fast Electric derscriptions.
The number of turns refers to the thickness of the wire wound around then armature.
The less turns the thicker the wire so the higher currents generated.
The armature is a fixed size so the less turns the thicker the wire.

Bob

[Prophet]

as far as im aware .. in rc cars 15 turns motors are more torque then outright speed so 20 turns is an equal mix of torque to speed where as 27 turns are full speed and little torque.. mind you this is rc cars were on about not boats .. so which ever motor u decide to use ,,. make sure the esc can support up to that motor due to the load the esc has to bare to power the motor so using a 15 esc with a 27 turn motor = fire!! easy solution.. use a 27 turn esc with all motors under 27 turns this way u always get the power and no burnt out escs :)

 feel free to correct me its been many years since i used rc cars parts (normally i buy full kits with electric boat motors now, less hastle).

[knoby]

sorry, think you got it the wrong Way round Prophet. 15 turn esc ok with 27 turn motor  27turn esc will catch fire with a 15 turn motor. The lower the turns on a motor the more current it draws !!!!  The lower the turn rating of an esc the more current it cam handle!!!

Cheers Glenn

[HS93 (RIP)]

sorry, think you got it the wrong Way round Prophet. 15 turn esc ok with 27 turn motor  27turn esc will catch fire with a 15 turn motor. The lower the turns on a motor the more current it draws !!!!  The lower the turn rating of an esc the more current it cam handle!!!

Cheers Glenn

Glen is correct, over the number of turns the less the more amps it draws, but unless you know the age of the motor it could be a 35, 27 or now 19 turn as they have changed the number of turns for stock or "spec" motor as now seem to call them , it has reduced in turns as battery technology improves to take advantage of the extra power available, 35 turn was about when nicads where 1200mah   27 came about when packs reached the 1600mah, and now 19  now they have 5000+ mah.
the 19 turn info came off the BRCA web site...but you have to remember the Americans ROAR in the past have run different winds. so it is confusing they are normally labeled the number of turns.

peter

[Nige52]

Thank you all for your replies
The reason I asked is because I often see for sale on ebay, Mtroniks speed controls, of which I use mainly Marine 25amp. The ones I was asking about are normally called 'Eco 27' or 'Eco 20' 'Suitable for motors down to 20, or 27 turns'
It is this phrase which was throwing me, most of my brushed motors are 550's or Graupner speed 600's or the occasional 700bb turbo. I was wondering if these 20 or 27 wind ESC's could be used with my motors.......

[Shipmate60]

Not really,
The motors you use are quite power hungry so will need  at least a 15 amp controller, but the 25 amp you use should be fine.
Don't forget to fuse for 20 amps though.

Bob

[Shipmate60]

Topic Tidied up.

Bob

[Nige52]

Not really,
The motors you use are quite power hungry so will need  at least a 15 amp controller, but the 25 amp you use should be fine.
Don't forget to fuse for 20 amps though.

Bob

Bob,
Why oh why didn't I take your advice?

I have been offered an Mtroniks Viper 15t.......which is suitable for motors down to 15 turns. I take it that this esc is more than enough to handle a Graupner speed 600?

Today at the pool..............

[malcolmfrary]

The big trouble with the "turns" rating is that it assumes use in a buggy - typically this meant 6 cells of NiCad feeding a 540 of some description.  Fuse at between 2/3 and 3/4 of the ESC max current rating, if this is less than the motor wants at startup, you need a bigger ESC. 
Most Many ESCs have some form of current limiting, but the fuse is needed in case a problem is created before the current sensor resulting in the entire energy content of the battery dumping, and converting into heat, inside the ESC.  So this fuse is really protection for the boat, to prevent it giving itself a Viking funeral out on the lake.

[Nige52]

My self destructing ESC was caused by the feather..............
Our lake is full of Canada Geese, my poor boat got a tough quill wrapped round the prop which wedged itself round the rudder assembly = instant smoke. I did think though that these esc's had a cut off of some sort in case of this sort of entanglement? That's what the blurb says anyway, ah well.

[Shipmate60]

From experience a good few years ago.

Bob