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Old 09-12-2013, 06:15 AM
  #33  
philspit
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Hello,

Generator for the 35% Cessna 185 Skywagon from Tmmy with Auto Pilot
For what a generator:
  • We want to generate a voltage between 4.5 and 60V with maximum 30A to charge LiPo and NiMh batteries.
  • The generator has to give also the power to all our systems like Autopilot, Ignition, Receiver and video system.

What have to do the generator:
Hi have to give us a voltage between 4.5 and 60V with maximum 30A

What we need:
  • Brushless motor
  • 3 Phase Diode Bridge Rectifier
  • Regulators input 4.5-60V to 4-24V

The input from the brushless motor:
We think that a motor whit a KV between the 160 and 250KV is the best for us project.
If we take a 160KV motor with a ratio of 1:3, it's mean that if the Mintor 220 on idle have a RPM of 1000 the motor gone have a RMP of 3000 that gone give us 18.75V.

3000RMP/160KV=18.75V

So, when the engine is on idle we have in off voltage too give on the regulators.

Specification of the brushless Motor from Great Planes GPMG4805:


  • Can Diameter: 3.14" (80mm)
  • Can Length: 3.35" (85mm)
  • Shaft Diameter: .39" (10mm)
  • Mounting Space Length: 3.83" (97.3mm)
  • RPM/V (kV Rating): 160
  • Input Voltage: 33.3-55.5V (9-15S LiPo)
  • Connector: 6mm bullet plugs
  • Max. Constant Current: 135A (at 12S)
  • Max. Continuous Power: 7500W
  • Max. Surge Current: 150A (at 12S)
  • Max. Surge Power: 8400W
  • Max. Constant Watts: 7500W
  • Weight: 52.2oz (1480g)

The regulators:
  1. Output of 12-14V for charging 4 PowerBox 4000mAh 2S LiPo batteries. We don't need balancer because the balancer is included in the PowerBox batteries. So, only a alimentation of 12-14V is necessary.
  2. Output of 12.4V to charging 2 batteries LiPo 3S 3000mAh 20C.
  3. Output of 4.8V for lights system and charging NiMh battery of 5300mAh
  4. Output of 4.2 to 26V for the autopilot supply.
  5. Output of 6V for the receiver, servos and ignition.
  6. Output of 9 to 16V for the video system.

The questions that we have:
  1. If the engine have a RPM of 5000, the Motor gone have a RPM of 15000 that gone generate 93.75V. Gone this support the Motor GPMG4805?
  2. Can we have 1 "3 Phase Diode Bridge Rectifier" for the complete system? We find one for 40A 1000V.
  3. Can we mount all the regulators in parallel after the 3 Phase Diode Bridge Rectifier?

All your comments or ideas are welcome
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