Pancake electric motor pre rotator

[Gyro jeff]

I am a electric motor guy but not engineer how much HP to spin 23ft skywheel rotor blades . think permeant magnet brushless would also generate power and electric assist

 

[GeneralPatton]

Well, To spin my RAF2000 30 ft blades to 150 rpm, in an experiment, it required about 2.5kw of power to the flex cable via starter motor @ 24vdc for 30 seconds.
I used a Pulse width motor control, 200 amp capacity. 1000 rpm under load.
maybe this helps,
Phillip

 

[okaneco1]

Where did you find the equipment needed? I have a shorted out soft start for 28' blades. I would like a more modern controller.
Kevin

 

[GeneralPatton]

Try. Kelly motor control on internet search

 

[Gyro jeff]

Well, To spin my RAF2000 30 ft blades to 150 rpm, in an experiment, it required about 2.5kw of power to the flex cable via starter motor @ 24vdc for 30 seconds.
I used a Pulse width motor control, 200 amp capacity. 1000 rpm under load.
maybe this helps,
Phillip

use starter motor?

 

[Gyro jeff]

Where did you find the equipment needed? I have a shorted out soft start for 28' blades. I would like a more modern controller.
Kevin

not working yet

 

[GeneralPatton]

Yes I used a starter motor from Subie EJ22, coupled to prerotation cable input, as a test only, used 24 vdc , the starter will handle that, produced 150 rpm , used soft start motor control, 24vdc@200 aMPs for about 30seconds.The controller was a proportional pulse width type, many available, no resistors used, a pancake type will use a brushless type specific for the type and current.
24 v x 100 amps= 2400 watts / 768 = 3.125 horsepower, that’s the power needed to spin a 30 ft rotor. To handle current inrush, the controller must be rated 75% above needed current.

 

[okaneco1]

I am looking for a person to rebuild this soft start. It was shorted out last spring. I have the part numbers for the componets
Kevin

 

[Sv.grainne]

Do you have a schematic?

 

[Aerofoam]

We use brushless Dc motors and speed controllers for many UAV's
There are small geared and outrunner motors that have over 100A capacity at 60v.

The solid state speed controllers are programmable and can handle soft starts.
You can probably find something on Hobby King, it takes some leg work to figure out the
right combination, but it's out there....
I will look into this in the near future, I think the whole assembly with battery could weigh less than 12lbs....

 

[Jean Claude]

The aerodynamic power required with our usual trim settings is around : P = 0.005. ρ . chord . Ω^3. Radius^4 (Metric units) .
0.005 is for Cd/4

Add 20% to obtain Ω in about 30 s

Then we should take acount the efficiency of the electric motor (only 0.5 if car starter motor).

To calculate the current, divide P by the voltage U, but bear in mind that U is about 0.7 U nominal battery , due to its internal resistance. This increases the result

 

[Jazzenjohn]

You might find some helpful info from this old thread.

Prerotator power required vs RRPM

I've been playing around with a new prerotator. I have test gear on it that shows how much power is required for different RRPM's. The data confirms the rough estimates most people use. Mine is a double chain reduction so it should be about 90% efficient. Here's what I get: 750 watts ~ 1 HP ~...

www.rotaryforum.com

 

[okaneco1]

Do you have a schematic?

I don't. All the part numbers were etched off each part, the designer didn't want any duplications made, and also almost impossible to repair. I had a guy attempt to sort out the parts and I think he came pretty close.

 

[okaneco1]

I am looking for a person to rebuild this soft start. It was shorted out last spring. I have the part numbers for the componets
KevinView attachment 1159561

 

[okaneco1]

Do you have a schematic?

yes see below, in another post

 

[okaneco1]

yes see below, in another post

 

[okaneco1]

I an glad to announce that the soft start module is fixed and I can pre rotate up to 110 RPM

 

[MikeBoyette]

I an glad to announce that the soft start module is fixed and I can pre rotate up to 110 RPM

That's awesome Kevin. Did you find someone to do it or did you figure it our yourself?

 

[okaneco1]

That's awesome Kevin. Did you find someone to do it or did you figure it our yourself?

One of our Chapter 34 member's father, loves to tinker with small electronics and figured out the logic and sequence of the components, not only do I have my soft start fixed but I have a backup module

 

[Resasi]

Congratulations on your persistence...and success.