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[ray123]

hi all looking for some help /advice   for a speed control for a very large motor!! = motor is from a mobility scooter    its 6inch dia markings on the motor are 24volt  390watts  2400rpm   the motor is  for a large model tug  58inch loa & weighing about 85lbs     driving a 5.5inch prop   thank you 

[HMS Invisible]

Advice: Tell the readers what voltage you are considering.

[Tug Fanatic]

Ray

One thing to be aware of is that a motor this size might well have a very high start up current.

I built a tug with a Sinclair C5 motor and had that problem. At the time (1990's) I couldn't find a model type rc esc that would handle it but things might be very different now. I considered both a mobility scooter controller and an electric outboard controller driven by a servo and pulleys but didn't pursue either.

Does your motor run in both directions of rotation?

PS This is going to test your baggage allowance on your West Coast US trips!

[HMS Invisible]

...
One thing to be aware of is that a motor this size might well have a very high start up current.

I built a tug with a Sinclair C5 motor and had that problem. At the time (1990's) I couldn't find a model type rc esc that would handle it but things might be very different now. I considered both a mobility scooter controller and an electric outboard controller driven by a servo and pulleys but didn't pursue either.
...

Indeed so. And a lot of energy stored in a magnetic field. The way to kill an esc with a high current motor is a fast run then slam into reverse.

Yes, the C5 motor would noticeably run better with modern processor based controllers from year 2000 onwards.
The use of higher power motors was the reason for the 4kHz motor frequency & the slow throttle ramp options in the FR40.
 8kHz would have been better but it would have required a faster processor and bulky, low-ESR capacitor as found in brushless escs. There's a hint. (Quicrun)

But at what voltage?

[Martin (Admin)]

 
Something like this?

 You might have to do a mechanical servo to knob thing...


https://uk.robotshop.com/collections/motor-controllers
 
https://packing-machinery.shop/products/ds-100-motor-speed-regulator?variant=20922165723194&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gad_source=1&gclid=Cj0KCQiAwbitBhDIARIsABfFYIJfwgioGBXpDiAtJ7227cd6FBshTOrcd0k-XB23VJ3NImaRJC3LK3gaAkrFEALw_wcB
 
https://www.amazon.co.uk/Akozon-Brushed-Controller-Reversible-DC10V-55V/dp/B07XXQHFGG/ref=asc_df_B07XXQHFGG/?tag=googshopuk-21&linkCode=df0&hvadid=658680989487&hvpos=&hvnetw=g&hvrand=13178257542992994404&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9046216&hvtargid=pla-1658589982276&psc=1&mcid=a176a40dc32a37a8879d8f25e415e124

[HMS Invisible]

24 volts is not a problem for many rc  escs nominally rated at 12 volts.

I can explain the why not , the effective safety measures and a precautionary test to reassure.
 The chore would be pointless if ray123 will use 12 volt.

[Tug Fanatic]

I await the voltage with interest. 12v is 1200rpm unloaded.

[Allnightin]

I used a home made resistor switching circuit to control the two large 24V DC motors I had driving a 1/32nd scale Type 42nd destroyer (4.5m long) when breaking the Guinness 24 hour record back in 2002.  Each motor (ex shower boost pump) had been rewound to pull about 6 Amps when turning the props at about 1500 rpm and connected direct to the battery.  The switcher network was designed to progressively reduce the in circuit resistance as a servo arm extension swept over a set of microswitches allowing about (from memory)about 4 or 5 forward speeds and smaller number astern. I ended up adopting this sort of approach after several attempts to use conventional model ESCs because they kept failing after several hours of near continuous running at full power - reversing relay contacts welding together was one typical problem.  This design was actually quite cheap to build and proved very reliable in use. The main disadvantage was the size and weight which was the one thing that didn't matter in a hull that needed about 100 lbs of ballast anyway.  I have the resistance calculations somewhere if you are interested in this method.

[ray123]

thank you for all the input       the guy will be useing   24volt      when we did bench test the motor (on 24v) i must say it had a huge torque kick       btw  he only has the motor and no other electronic bits from the scooter 


if there's  anything that is ready built? to use that would be great!  thank you

[chas]

Mtronics viper marine 40 hv. Rated at 24 volts, 40 amps. You'll probably be pulling 15 to 17 amps, possibly less depending on the load the propeller puts on the motor.
 I would email them with details of the motor before buying, just to be sure about the multi pole compatibility and surge current.
Chas

[Martin (Admin)]

 
https://www.mtroniks.net/prod/Boat-Speed-Controls/Viper_Marine_40_HV.htm

[Martin (Admin)]

 
Ebay:

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2332490.m570.l1313&_nkw=rc+speed+controller+esc+24v&_sacat=0

Amazon:

https://www.amazon.co.uk/24V-DC-Electric-Motor-Speed-Controller/s?k=24V+DC+Electric+Motor+Speed+Controller
 
 

[unbuiltnautilus]

https://www.mtroniks.net/prod/Locomotive-Speed-Controls/DCi-120-24.htm


I think this type of motor will rapidly blow up most marine speed controls currently available. Mtroniks do a range of speed controls for big gauge sit on model railway locos. These also use ridiculously big motors.. The only problem with this plan, they are manual operation via a dial.


I would look at a really big brushless motor in the 300Kv range, then run on 12v instead, let the C5 motor go!

[ray123]

again thank you for the input mayhemer's    ill have to report back to the friend  with  the info 

[HMS Invisible]

I suggest you ask him, or anyone with surplus escs, what they have to hand.

[NickelBelter]

Dimension Engineering makes most of their speed controllers able to operate from 6-30v, this is the highest amperage model they offer
https://www.dimensionengineering.com/products/syren50
You'll have to order a male servo lead as they don't come with one attached, but they do have screw terminals so no soldering required.

[Treble]

Would suggest you give 4QD a ring on 01487 450520 to discuss the suitability of their DNO unit , as well as their other offerings .

[HMS Invisible]

This £21.90 Inc Post & VAT, 12 to 24v ESC arrived a moment ago from a UK Ebay vendor, ordered last Tuesday. I'll see how things go in the coming days.

I would be interested to know how the other suggestions compare on delivery, cost, and performance. It is generally useful to know whether mentioned candidates are recommended, have been used in real world conditions by the posters, and if they know the performance specification or the suggestions are just a hit from an Internet search.

My guess is, at a stretch, the ubiquitous £4 Chinese 1" square ESC that has the minimum 15% (which is terrible!) throttle can be adapted for 24v use. However I think a voltage nearer 12v will be used in the end here. I wonder if Tug Fanatic is thinking that.


Back to the £21.90 ESC: See to the left of blue cables.
Surface mount transistors dissipate most of their heat into the printed circuit. Unless there are upward facing component tabs, this heatsink is largely cosmetic, and the ESC isn't unique in that respect. You'll see this if you dissolve the epoxy of your burned out esc in a sealed polypropylene tub filled with dichloromethane. It takes a fortnight to turn to jelly.

[HMS Invisible]

As I thought!
I'm neither praising nor criticising the ESC I just ordered.
I have not even bench tested it but I confirmed my own long held belief before I state the minimal difference(s) in a higher voltage esc.

Question: What is the technical or component difference between a 6-12v esc and a 12-24v esc other than price, if any price difference?


Answer: In this example the difference is limited to the internal bec being the switching type. The 24 ( 6 parallel H-bridge) FETs are typical 30volt ones. Though Maplesemi brand or mainland Chinese knockoffs as EEVBLOG youtube channel will imply.

Question: What are the differences with linear bec and why do they matter?
Answer: You can search the Internet for chapter and verse.
Here is my summary:-
Switching bec steps down the dc voltage like a transformer does with ac and at an efficiency of around 85%. Linear bec chops off everything above 5 volts so if the esc runs off a 13.8 volt battery the efficiency is 36%.
If there is a heavy servo load of near one amp a 5v linear bec dissipates near 8 watts. That's as much as an air cooled esc can get rid of in total, including the heat from drive transistors. This is also why, going back three decades, I'd give away power resistors with speed controls to those who were going to use high voltage inputs. The resistor diverts some of the waste heat away from the esc heatsink.
Linear bec beats switching bec when the voltage is near 5 volt. The efficiency is fine but it maintains a stable 5 volt at Vin=6 where a switching bec needs Vin=7 or higher. The technical term you see on regulator component data sheets is 'dropout' voltage.

Question: What are the other differences from a 6-12v esc?
Answer: In this case there is none.

Question: What is the implications?
Answer: If you are not using the bec then you may as well use a 12v ESC, keep battery wires short and perhaps add a low esr capacitor on the 20 or 24 volt line to limit voltage transients. You still need to know what you are doing.

If anyone else has got more information then please share it on the forum. I would have thought quoted 24 volt rated escs is pushing it with 30v FETs because the breakdown voltage in a bridge at elevated temperature falls below 29 volt. Two 12v Pb batteries could reach above 27 volt.

[destroyer42]

Ray,
Have a look at ampflow
 https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjA08bMtIiEAxV8WkEAHYS6B_MQFnoECBUQAQ&url=http%3A%2F%2Fwww.battlekits.com%2F&usg=AOvVaw1MFv_7Auy2RdBtJ0eH1TEl&opi=89978449
Robot Battle kits have large amp esc & motors


Colin

[ray123]

hi everyone  thank you for all the input /help for a speed control for the motor  i have found one  at  4QD   they are in the uk  'Cambridge'  very helpful people 

[HMS Invisible]

Please tell us what you have ordered, how much it cost and if all goes well.
Of the other suggestions, the £22 Chinese Ebay one impressed the new owner and five more are on order.

[Damien Mac]

Sabertooth ESC's are good for large motor'sNot cheap but very good at what they do

[Damien Mac]

Larger of the dimension engineering ESC duals , think this size is for larger models..ie robotics and TanksThis shows the screw terminal connections mentioned earlier by Nicklelbelter

[HMS Invisible]

As I thought!
I'm neither ...Two 12v Pb batteries could reach above 27 volt.

An Aliexpress vendor has provided a lot more info on the heatshrink covered versions of the aforementioned esc and in a way you will understand. Their 10.5v minimum voltage tallies with my test and that suits 4s Lipo or Li-Ion.
 You get no data in the Ebay parcels and sweet FA in the Ebay sales auction apart from the function of the three position switch in mistranslated English. It should read (1) no brake, (2) drag or car brake, (3) forward only. The heatshrink covered Aliexpress versions omit this switch.
I can't shake the thought someone connected reads modelboatmayhem posts on their products. That's no joke, by the way.


 The version attached to the box and heatsink by silicone and supposed to be DIY resin potted is still cheaper via Ebay
£16.81, XT60 plug, Inc taxes and post Estimated by Fri, 27 Dec - Mon, 6 Jan

From https://www.aliexpress.com/item/1005006317820464.html

Dimensions: 7.2*3.5cm
ESC working voltage 10.5V-26V
Controller input pulse width is 0.8MS-2.2MS 1.5MS is the midpoint

Wire: 14AWG
The power plug of the ESC is: XT60/T
The motor end plug is 4mm bullet head single plug (one for one) or double plug (one for two)

Built-in ESC,
A total of 24 high-power MOS on the front and back
H-bridge, each road has 6 high-power MOS on the lower arm
The forward and reverse power is the same, it is not a design to delete the reverse output power
The actual continuous current peak value for both forward and reverse rotations is 100A
ESC rated power 1000W
640A is only the label of the brushed ESC, not the actual current value, and has no practical meaning.

Recommended motor matching,
In order to avoid excessive current when the rotor is locked, it is recommended to reserve sufficient power margin
12V: 3* 540 or 3* 550 or 2* 775 or 2* 795 or 1* 895 or 1 *997
24V: 2* 775 or 2* 795 or 1 *895 or 1 *997

ESC work
Switch UBEC 5V 3A can drive two 25KG servos
It is not a 7805 linear regulator, so two ESCs cannot be used to power the receiver at the same time

LED indicator:
Steady bright-normal work
Intermittent flashing--throttle is not in the safe midpoint position at power-on
Continuous and fast flashing-loss of throttle signal

1. After power-on, the LED indicator flashes slowly for 3 times for self-test, after the self-test, it is always on to indicate normal operation
2. If the throttle is not in the neutral position at the time of power-on, the LED will flash intermittently. At this time,
    you need to adjust the throttle position to the neutral position, and the LED can work only after the LED is always on, otherwise the ESC cannot work in the flashing state.
3. If the throttle signal is lost, the LED flashes quickly and the motor will stop rotating

Precautions
If one receiver uses two ESCs at the same time, you need to cut off the red positive wire in the middle of the BEC signal line of one ESC,
and one ESC can supply power to the receiver. If two ESCs supply power to the receiver at the same time, it will be burned.

There is only a forward and reverse ship mode, no brake mode for cars.