1st of it's kind. Battery powered chicken plucker...what!

zerberfert

Member
Joined
Apr 14, 2020
Messages
58
Hello again,

We bought a bunch of chickens about 2 weeks ago, 70 Cornish crosses (meat chickens) and 14 egg layers.


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Call me a prepper, or a doomsdayer, but meat prices were getting high and I guess we're bored.

The meat chickens are suppose to get to 6 pounds in 6 weeks. They are growing fast.

We are going to kill 5-10 meat chickens a week and I wasn't looking forward to plucking that many chickens at once. So of course, time to look on Youtube.

I found people making chicken pluckers (de-feather). So I said why not.

I already had a DC motor and I just made a 24v batter for my Kweld spot welder, so time to get to work.


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I got a few questions though.

Here is the variable speed controller I am using:


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It is using 2.5 amps from the battery:

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However the DC motor is using 9 amps:

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The controller is varying the voltage from 0-24 volts however those pictures are taking at the same speed.

Is the speed controller doing something to boost the amps?



Zerb
 
Your speed controller is probably converting the full signal DC voltage into Pulse Width Modulated signal (PWM). But changing the length of time that full voltage is applied to the motor, it can change its speed. So, let's say that it does 50% duty cycle. The pulse is ON for 50%, and OFF for 50%. Now, this is usually over the course of a second. This switching could happen about 1000 times a second. So, the switching would be ON for 5ms, OFF for 5ms, ON for 5, OFF for 5, etc, etc. Or it could be 70% duty, and that'd be ON for 7ms, OFF for 3ms, etc. (i think i got the right ms for the time; but ya get the idea, I hope)
So no, it doesn't change the "amps", just the time that voltage is applied.
 
The PWM controller will be working like Korisahn said.
But combined with the winding inductance of a typical DC motor this ends up working like a buck downconverter.
So you can have more amps out than amps in with a stepdown of volts.
It's:
Power in = Power out, less some losses (eg 20% ish losses)
Power in = 24V x 2.5A = approx 60W
Power out depends on voltage but for say average (PWM effect) 8V out, that's approx 7.5A (losses ingnored)
The meter on the motor side there is probably getting spooked by the voltage spikes there & reading a bit high.
If you put a high speed diode across the motor terminals (reversed so as not to short it) that will calm down the spikes - don't use a cap, that'll stress the PWM controller & reduce the buck effect.
 
Generally, the controller sets just the output voltage. Can be a "PWM" method (as described above) that sends pulses of 100%/0% that averages out to the set level. Or it can be a "buck converter" type that outputs a stable lower voltage.
In any case, it's generally the motor that "decides" how much current to take given a voltage.

That "decision" mostly depends on the load on the motor.
A free spinning motor might draw only 0.5A, but draw 1A with heavy machinery attached to it, and 3A with a fat chicken rubbing against it.
Accordingly, a 60W rated motor will use much less power than 60W when spinning freely, and much more than 60W when under heavy load.

As Redpacket mentioned above, physics dictates that
InVoltage * InCurrent = OutVoltage * OutCurrent , so in this case...
24V * 2.5A = OutVoltage * 9A , allowing us to deduce
OutVoltage = 6.67V , or thereabouts due to losses in the circuitry

Recommend putting some sort of cover on the belt & pulley - they are notorious accident magnets.
Not sure which end the chicken goes in, but also probably a good idea to cover as much of the plucker as possible to avoid stuff getting flung around...?
 
Thanks for all the info. Didn't know all that. Learn something new everyday. That's why I like this forum, everyone willing to educate me. lol
 
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