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-   -   ESC with DC power supply instead of battery (https://www.wattflyer.com/forums/showthread.php?t=75283)

ramses 02-04-2015 08:54 PM

ESC with DC power supply instead of battery
 
Hi, I have 2 questions related with ESCs.

1.) I have 30A Emax ESC. I want to connect it to DC power supply instead of li-po battery. If I set the desired voltage and max current from DC power supply, is there any problem? Motor max current 15A and ESC max 30A. Please share important points with me.

2.) I will send PWM signal from controller instead of PPM(that is generated via RC controller). Do I have to any other setting to drive motor on ESC?

CHELLIE 02-04-2015 09:22 PM


Originally Posted by ramses (Post 968115)
Hi, I have 2 questions related with ESCs.

1.) I have 30A Emax ESC. I want to connect it to DC power supply instead of li-po battery. If I set the desired voltage and max current from DC power supply, is there any problem? Motor max current 15A and ESC max 30A. Please share important points with me.

2.) I will send PWM signal from controller instead of PPM(that is generated via RC controller). Do I have to any other setting to drive motor on ESC?


1. As long as you have sufficient voltage and Amp output from your DC power supply there should be no problems, I would think that if your DC power supply is able to deliver at least 20 amps, you should have no problem, the esc and motor dont care where the voltage is coming from, as long as there is enough dc voltage and amps, you should be fine.

2. If i read your second question right, it sounds like your talking about using a servo controller to operate the esc and motor, That should work fine . the esc is just looking for a signal to make it work. or you can use your transmitter and receiver to generate a esc / motor signal. the servo controller should only see about 5 to 6 volts input no more than that, or you may burn up your esc.

crxmanpat 02-04-2015 10:17 PM

Also be sure your DC power supply does not provide more voltage than your ESC can handle. Not sure if that ESC is only good to 12v, or 18v.

ramses 02-05-2015 06:56 PM


Originally Posted by CHELLIE (Post 968117)
1. As long as you have sufficient voltage and Amp output from your DC power supply there should be no problems, I would think that if your DC power supply is able to deliver at least 20 amps, you should have no problem, the esc and motor dont care where the voltage is coming from, as long as there is enough dc voltage and amps, you should be fine.

2. If i read your second question right, it sounds like your talking about using a servo controller to operate the esc and motor, That should work fine . the esc is just looking for a signal to make it work. or you can use your transmitter and receiver to generate a esc / motor signal. the servo controller should only see about 5 to 6 volts input no more than that, or you may burn up your esc.


Thanks for your feedback :)
2.) I will generate PWM on Beaglebone(of course it doesn't matter any microcontroller can be) instead of using RC transmitter. I wonder that: is there any restriction on ESCs against PWM signal that generated by microcontroller?

kyleservicetech 02-05-2015 08:33 PM


Originally Posted by ramses (Post 968165)
Thanks for your feedback :)
2.) I will generate PWM on Beaglebone(of course it doesn't matter any microcontroller can be) instead of using RC transmitter. I wonder that: is there any restriction on ESCs against PWM signal that generated by microcontroller?


Nope, done that myself several times with Microchip "PicChips".

You need to send a repeating pulse to your servo, with pulse width from 1.0 to 2.0 milliseconds. And, repeat the pulse every 20 milliseconds or so.

As far as using the PWM feature available on the PicChips, I found just used a variable pulsewidth by a simple 1 - 2 ms time delay for the "On" pulse, and a second 20 ms time delay for the "Off" pulse.

Most recent project was to use a PicChip timer to operate a servo, once per minute going to full clockwise, then return to counter clockwise. The software just output a 2 MS pulse, about 50 times, then output a 1 Ms pulse 3000 times. Simple, and it worked.

At least with the PicChips, using their PWM feature didn't have the resolution I could get with the simple time delay pulse generator program.

The arm on that servo pushed the shutter button on my Canon SX20IS camera.

CHELLIE 02-05-2015 08:34 PM


Originally Posted by ramses (Post 968165)
Thanks for your feedback :)
2.) I will generate PWM on Beaglebone(of course it doesn't matter any microcontroller can be) instead of using RC transmitter. I wonder that: is there any restriction on ESCs against PWM signal that generated by microcontroller?

I am not aware if there is any restrictions on ESC against PWS signals, maybe one of the electronic Gurus here can chime in. if you have any issues in generating a signal with your microcontroller, here is a servo tester dedicated for rc use.

http://www.ebay.com/itm/New-Turnigy-...3D171373022360


New
Servo Tester
760LV-HV
Dual Pulse Width
Selectable
In Stock, US Seller, Fast Shipment
The Turnigy 760HV servo tester was custom designed to be the most accurate and accommodating servo tester available. It's quality case design reflects the thought and design of this device.

Designed to handle Narrow (760us/560Hz) and Normal (1520us/66.6Hz) pulse servos plus being able to run with as little as 3v up to 12.6v. Making this a servo tester you can use with almost any servo!

The 760HV's versatility comes from the high-spec potentiometer and it's high-end NEC chip which can handle low(3v) and high(12.6v) voltages.

Spec.
Servo Type: (760us/560Hz) or (1520us/66.6Hz) HV or Standard
Input voltage: DC3~12.6V (1~3S Lipoly)
Plug:
Futaba & JR
Weight: 35g
Dimensions:
63x55x21mm
Attention:
Do not input a voltage that is higher than your servo can handle.

kyleservicetech 02-05-2015 08:39 PM

Servo Driver
 

Originally Posted by CHELLIE (Post 968177)
here is a servo tester dedicated for rc use.

Hi Chellie

That looks good, and should do the job.

But, my PicChip cost 99 cents, and can be programmed to do many things automatically.

With an evenings worth of programming anyhow :D :eek: :cool:

I made a couple of them for fellow club members that wanted to fly electric control line models. It was programmed to "first blip the motor" as a warning, then 10 seconds later, quickly ramp up to full power. Then run for exactly 4 minutes, then again blip motor power in flight, then cut power 15 seconds later. Wouldn't take much to include computer type jumper clips to allow digital changes in time for full power, increasing by one second increments to 6 minutes or so. No one has asked for it yet.

The entire circuit consisted of one PicChip, one resistor. That's it. (The resistor is needed for on circuit board reprogramming)

CHELLIE 02-05-2015 08:42 PM


Originally Posted by kyleservicetech (Post 968178)
Hi Chellie

That looks good, and should do the job.

But, my PicChip cost 99 cents, and can be programmed to do many things automatically.

With an evenings worth of programming anyhow :D :eek: :cool:


:D There are cheaper servo testers out there, but you get what you pay for IMHO :D I have had great luck with turnigy products, so i tend to try to stick with them, Take care and have fun, Chellie


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