1898

Item 1898

DESIGN ~ Electrotor-SloMo ~ Control - Electric - Power - Outrunner Project

Also see;

MAKE ~ Electrotor-SloMo ~ Control - Electric - Electronic - F&P Development

BUY ~ Control - Power Train ~ Electric - Kelly Controls

Notes:

PC says that MOSFETs are much more efficient than IGBTs. He mentioned some like 99% to 85%. He said that EGBTs are required for higher voltages. Look further into this.

Considerations:

Run all the coils in parallel and use a pair of MOSFETs for each coil.
Locate the Power Transistors at the motors and possibly inside the hollow inner post. The controller, which probable does not produce much heat, can be separate. This will result in the shortest length of power wiring.
Run the copper phase wires openly into the hollow core were unclad busses would be located. The area would be protested for intrusion and thereby provide additional cooling of the copper. The Wye copper wiring and its bus(es) would be located outside the stationary post (Base) .

Redundancy Considerations:

Have 2 controllers and each controller drive half of the coils in each motor. This will assure that both motors are receiving partial power if one circuit should fail.
This may also contribute to better electrical synchronization

A/ [Build 1] Stock F & P w/ Control by Kelly with Hall Effect Sensor:

Wires from Kepco power source to Kelly controller are 12 gauge, which are good for 41 maximum amps for chassis wiring.

Have the main power switch and the fuses from the batteries remote from the control board, Just as they ar on the Kepco power supply.

I have isolate the power wiring on the control board from the operator.

Key Switch:

When operation; wait a minimum of 12 seconds after turning the power switch before turning on the key switch.
From the meaning of the symbol the Key Switch is On-Off Single Pole, Single Throw = SPST
Alltrax shows 18 AWG wire from the key switch and it looks like the voltage is 48V.

A/ [Build 2] Modified F & P?

Notes:

SELECTING THE POWERSWITCHING ELEMENT

The first stage in selecting the correct power-switching element for your motor drive application is understanding the motor being driven. Understanding the ratings of the motor is an important step in the process as it is often the corner points of operation that will determine the choice of the power switching element. A sample of motor ratings for the motor types listed earlier is shown in Table 1. When dealing with motors, it is often useful to remember that 1 Horse Power (HP) is equal to 746 Watts. From the ratings in Table 1, the voltage, current and power ratings vary significantly with the different types of motors. Motor ratings can also vary significantly within the same motor type. A key point to note in Table 1 is the value of the start-up current (sometimes given as stall current or locked-rotor current). The startup current value can be up to three times the value of the steady-state operating current. As mentioned previously, it is these corner points of operation that will determine the necessary ratings of the drive element. Because of the various voltage and current ratings for the various motor types, the selected drive device ratings will have to vary as well, depending on the application and design goals.

Power Circuit:

This page shows the 'Power Circuit' for the F&P motor development.

http://www.unicopter.com/1741.html

The thinking is to used MOSFETs (or alternative) that are sized so that 12 of them will power a 6-phase 10-Kw motor. However only 6 of them will be used in the beginning, for driving and developing the 3-phase F&P motor.

To begin with the 'PWM' control input shown on the drawing will actually be from a handed-turned commutator via a couple of logic chips.

Consider using the 4 existing Albright relays for this build. Series wiring on their control and 2 * 72 parallels on their power wiring.

Parts:

Heatsink: for general information see; OTHER: Electrical - Control

Purchase 3 power transistors which are sized so that (3 x 2 [6-phase] x 2 rotors =) 12 of the size that can each handle 1/12th of the total power required by the ELECTROTOR-SloMo craft.

Mount 3 power transistors on one heatsink and eventually mount the 4 heat sinks on the aluminum back leg of the tripod.

Alternatively make one long aluminum heatsink as a structural portion of the strength of the back leg and the supporting for the seat and batteries.

MOSFET: for general information see; OTHER: Electrical - Control - Power Transistors

6-phase instead of 3-phase will mean that the power transistors are switching less frequently and this means that they will be cooler.

Looking into using IGBT.

IGBT: for general information see; OTHER: Electrical - Control - Power Transistors

Do not want Brake.

Want Inverter?

Want 6-pak?

Requirement appears to be, for one of the two 3-phases; 8Kw/ 2 = 4Kw, which at 150V will be 30A or at 300V will be 15A.

The following is 1200 V but it is a start at learning. Then select appropriate IGBT.

Phone main Electronic to purchase, or get price.

Associated Pages:

Last Revised: August 2, 2011