Adjustable volts and amps jig - How to??

[ecologito]

ello everybody, I am into building my own CD motors for planes. Now I need to take this to the next step.

Since it is hard to keep batteries fully charged and to run more accurate tests on my motors I'd like to make my own DC adjustable power supply.

I was looking at stuff I might need:

Volt panel meter:
**broken link removed**

**broken link removed**

Amp panel meter:
**broken link removed**



I am not sure but I am guessing I could use a computer power supply like this:
**broken link removed**

The power supply description says it has an output of +12V 24A ( perfect ) to test CD motors.


What I have no idea is how to connect them together or how to regulate volts ( from 7 to 12 ) and amps ( 1 to 24 ) going out of this jig. I have no electronics knowledge and there is only one thing more dangerous than an unknowledgable person, an unknowledgable person with initiative

If somebody could direct me on stuff I need and a diagram or if this is possible.

 

[Roff]

What is a "CD motor" - or are you dyslexic?

 

[ecologito]

What is a "CD motor" - or are you dyslexic?

Almost got me but on, I am not. My english might not be perfect haa haa

I am talking about motors that I take out of CD rom Units for Rc planes, I rewind the motor, replace the magnet ring with strong magnets and here is the result...

Motors that can pull 23 amps at 11 volts ( that is if you set it up with a big prop)

 

[Roff]

On and on! :lol:
Cool motor! I had done a Google search, but if they were found, I missed them. Is there a web site about CD plane motors?
Unfortunately, I don't have a simple answer to your question, but maybe one of the other guys does.

 

[ecologito]

On and on! :lol:
Cool motor! I had done a Google search, but if they were found, I missed them. Is there a web site about CD plane motors?
Unfortunately, I don't have a simple answer to your question, but maybe one of the other guys does.

There are some website with this stuff:

www.little screamers.com
www.gobrushless.com

here are 2 videos of my motors:

**broken link removed**

**broken link removed**

 

[Roff]

So do you power these off lithium-ion batteries, or ???
How much flying time do you get from a charge?

 

[audioguru]

The Little Screamers are extremely lightweight, powerful and maneuverable.
This summer I glued together and painted a styrofoam plane I won. The latex house paint I used was way too heavy but held the plane together each time it crashed. I used a cheap geared motor that just barely had enough power and the plane flew something like a brick made from cereal. The PWM motor speed control circuit I designed worked very well.
I used a heavy 8.4V Ni-MH battery with too much capacity for it to fly nearly all day!

 

[ecologito]

So do you power these off lithium-ion batteries, or ???
How much flying time do you get from a charge?

I power mine with Lithium - polymer batteries. You can get out of a 30 grams motor 17 oz. of thrust or more. usually 3 cell Li-polys are great ( 11.4 volts) and some planes using 1,500 mah batteries can fly up to 12 minutes depending on the motor. The batteries have to be high discharge ( 20C) if you have a hot wind motor that can pull more than 20 amps. Here is a video with data included to give you a good idea of what this little motors are capable of:

**broken link removed**


Now back to topic, can somebody help me?

 

[audioguru]

Those put-files take way too long to load.

 

[john1]

i did wait a while,
and tried twice,
i got the impression it wasn't going to load and gave up.

John

 

[audioguru]

I tried the Put-Files site at almost 3:00 in the morning and it took 10 minutes to load the 4+ minutes video (800 res) on my broadband connection.

At 10.6V the fantastic little motor drew 23.5A (249W!), ran a propeller at 18,950 RPM and had a thrust of a whopping 1lb-12oz. They measured its temp which wasn't too hot.

 

[ecologito]

Yup, that little motor can handle and deliver lots of power,

What about my plan of having a volt adjustable power supply that can handle up to 25 amps?

 

[Roff]

For US $80, I would **broken link removed**. A 300 watt supply, especially an adjustable one, is not a simple task, even for an experienced designer.
I don't think this one has adjustable current limiting, but do you really need it?

 

[eblc1388]

Yes, at $80 its much cheaper than building one.

Detailed Description
Perfect for Home, Shop and Hobbyist
Built-in Cooling Fan
Input: 115V AC, 60Hz, 500 Watts
Output: 6~15V DC(Adjustable)
22 AMP Constant/25 AMP Surge
Powers 6~15V DC Devices such as Cellular Phones, CB Radios, Scanners, HAM Radios, Autosound Systems, etc.
Screw Terminal Connectors
Crowbar Over Voltage Protection
Electronic Overload Protection w/ Auto Reset
Short Circuit & Thermal Protection
Fuse Protected
LED Condition Indicators
3 Prong Grounded AC Plug
Heavy Duty Cabinet & Heatsink with Anti€“Skid Rubber Feet

A crowbar protection on a variable output power supply. This is interesting. Hope it won't operate when one increases the output voltage.

 

[motion]

A crowbar protection on a variable output power supply. This is interesting. Hope it won't operate when one increases the output voltage.

It is probably designed to operate above the maximum voltage say 18V. Some of the series pass transistors become short circuited when they fail and these crowbars are designed to blow the fuse when this happens.