[PSUBS-MAILIST] Motor testing

[Alan via Personal_Submersibles]

Hank,
on a brushless motor there are the 3 phase wires compared to a brushed motors 2.
In addition I have opted for 3 hall sensors & a temperature sensor, which gives
you another 6 thin wires that take up less space than a single phase wire.
Hall sensors give me better low speed operation, but if they fail the motor still runs.
You have your 2 battery wires connected to the Vesc speed controller (inside the
hull). In my test setup there is a micro usb cable from the Vesc to the computer.
The temperature sensor is invaluable as I didn't have one in my last thruster
pool test & ran a thruster for 30hrs & cooked it.
The Vesc also has a temperature sensor & if either hit 80C the power is limited till 
the temperature drops.
In the attached photo you can see the cooling veins I was talking about. I will be
removing 2/3 of these as they are designed for air not oil cooling. I pulled this 
motor apart to re-solder a phase wire which had simply fallen off! The coil wire is 
soldered on to the phase wire & on this one they didn't do a good job.
Cheers Alan




> On 7/09/2018, at 11:19 PM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Alan,
> Pretty high tech operation you have going there.  I am curious how many wires it takes to run these?  
> Hank
> 
> On Friday, September 7, 2018, 4:57:18 AM MDT, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 
> Testing my new motors. I did an amp draw comparison between running them in air
> & in a low viscosity silicone oil. I ran them at varying speeds from 150 to 2,400 rpm,
> with no load. The speed controller is connected to the computer & I can monitor 
> the temperature of the motor & esc as well as Watts, Amps, rpm etc.
> In air I was only drawing around .2 Amps for the whole range.
> In oil strangely enough I was drawing less amps to begin with but this evened up at around 800 rpm. Bearings must have liked the oil. After this the Amp draw went up to 1 Amp at 2,400 rpm. There are veins at one end of the motor for cooling & these agitated the oil quite a bit as the rpm advanced. These are good for circulating the oil for much
> needed cooling but were a bit too aggressive. If it weren't for the veins there probably
> would be very little difference in Amp draw. I am going to grind off some of these veins
> & see how it goes. The oil had a massive advantage in cooling the motor but it looks
> like I can only run these motors continually at about 25 Amps off 48V. On higher Amp draws up to 40 Amps the temperature was climbing at nearly 1C every second untill it
> hit 80C, at which stage the systems over temperature protection cut back the Amps.
> Great to be able to dial in loads & speed on the laptop & get accurate motor performance data back. The screen shot is of the Vesc tool that is free! I know the Vesc
> motor controller runs brushed motors but I am not sure what diagnostics you could
> use on them.
> Cheers Alan
> 
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