1905

Item 1905

DESIGN: Electrotor-SloMo ~ Motor - Radial Flux - Overview - Outrunner Project

Overview:

Potential Improvements in the development of an Electrotor-SloMo motor that is initially based on the BUY ~ Motor ~ Fullsize - Radial Flux - Stock F & P.

Objective:

13.4 hp [10,000 kW] for each motor. 700 RPM, 100 lbf-ft [135.6N·m]

All testing and development on the F&P MUST be done for the 700-800 RPM operating range. Any high speeds are irrelevant.

Comparison between F&P (with stock laminates) and Megaflux MF0310025: December 8, 2011

	F & P (stock)	Megaflux MF0310025
Diameter of Airgap:	Approx. 9.75"	Approx. 9.75"
Number of Magnets [not pole pairs]:	48	48
Thickness of stator laminates:	1.0236"	1.02"
Weight [stock] (lb)	13.0	15.92
Voltage: (V)	48	48 / 150 /300
Current: [I] (amps)		30 / 18 / 11
Peak Current: [I_P] (amps)		202 / 118 / 74
Peak Torque: (lb-ft) ⁽²⁾		194 / 194 / 194
No Load Speed: [S_NL] [n0] (rpm)	74	338 / 617 / 779
Corner of Continuous Duty Area: (rpm - lb-ft)		325-28 / 600-28 / 755-28
Corner of Continuous Duty Area: (hp) RPM x T / 5252 = HP		1.73 / 3.20 / 4.03
Terminal Resistance: [R_M] +/-12%	30.9	0.095 / 0.263 / 0.691

(1) xxx

(2) Peak Torque is the amount of torque that the motor can produce without danger of demagnetizing the rotor. This torque is only available for short durations.

The Megaflux MF0310025 the Megaflux MF0410025 appear to only differ in pole count and diameter. The smaller has 48 poles and the larger has 64 poles; for an increase of 64 - 48 / 48 = 33%. The diameters of the airgaps are approximately are 9.5" and 12.25"; for an increase of 12.25 - 9.5 / 9.5 = 29%.

The Megaflux MF0310025 has a speed 600 rpm, torque 35 ft-lbs, from table in 2005 printout = 600 x 35 / 5252 = 4.0 hp

The Megaflux MF0410025 has a speed 600 rpm, torque 50 ft-lbs, from table in 2005 printout = 600 x 50 / 5252 = 5.7 hp

This is a 43% increase. Surprisingly the Speed does not change.

Note that the stall torques are 36 ft-lbs for the MF0310025 and 95 ft-lb for the MF0410025. ????

The Megaflux MF0410015 has a speed xxx rpm, torque xx ft-lbs, from xxxx = xxx x xx / 5252 = xx hp

For more information on stock F & P see; BUY ~ Motor ~ Fullsize - Radial Flux - Stock Fisher & Paykel

For more information on Megaflux see; BUY: Motor - Fullsize - Radial Flux - Inrunner - MegaFlux - MF0210, MF0310 and MF0410

It would appear that taking the F&P to 48 tooth from 36 tooth, or perhaps increasing the thickness by 50% will increase the HP by 33% and keep within the 'Continuous Duty Area, however this may not lift 300lb.

It does suggest that a reworked F & P will serve as an UAV for development of the Torque-pitch, Blade and Controller, while the motor is being upgraded.

For additional information see; All to be combined on one page at some time?

Initial Motor:

See; BUY ~ Motor ~ Fullsize - Radial Flux - Stock Fisher & Paykel

Database ~ Motor: Form - Specifications:

See: Electrotor-SloMo ~ Motor - Radial Flux - Specifications

Database ~ Motor: Form - Performance Spreadsheets:

Currently, hard copy in Binder: Motor - Specifications

Simplistic Consideration re. Volts x Amps to Linear Speed x Torque:

Consider two motors with identical characteristics except that A has 3 teeth (coils) (stator poles) and B has 6 stator teeth.

Therefore B will have twice the diameter of A

The linear speed at the circumference of both will be the same.

Now duplicate the A motor, mount this second A motor coaxially with the original A motor and connect their stators and their rotors.

Now both the A motor and the B motor will have the identical number of teeth and weight of copper etc.

A will have twice the rotational speed of A, but B will have twice the torque of A.

In other words; A and B are receiving the same wattage and they are putting out the same HP.

The difference is that B has a 2:1 electronic gearing.

Musings on Rotational Speed ~ June 26, 2010:

The mechanical linear speed of the Synchronous AC motor is determined by the 60 cycle incoming electrical power times the electronic gearing.

The mechanical linear speed of the Brushed DC motor is determined by this speed times the electrical gearing and this speed is determined by the torque and the opposing resistances and load.

The mechanical linear speed of the Brushless DC motor is determined by this speed times the electrical gearing and this speed is determined by the torque and the opposing resistances and load.

For a given load, any ability to decrease the resistances (by reducing losses ~ [~ PMMT section 4.2.7]) should result in a greater speed.

Armature winding losses.
Armature core losses.
Rotational losses.
Stray load losses.

Temporarily copied over from 1910
Projecting results from 50V Power Supply and 72V Batteries at No-Load:

Voltage	V Differential	RPM Differential	RPM - Star ⁽¹⁾	RPM - Delta ⁽²⁾
50 ⁽³⁾	72/50 = 1.44	120/62 = 1.93	62 RPM ⁽³⁾	107 RPM
72 (735) ⁽³⁾			120 RPM ⁽³⁾ ⁽⁴⁾	207 RPM
144 (150)		⁽⁵⁾	322 RPM	557 RPM
288 (300)		⁽⁵⁾	862 RPM ⁽⁶⁾	1,491 RPM ⁽⁶⁾

The Effect from Increasing Depth (thickness):

Weight:

Fisher & Paykel:

See: BUY ~ Motor ~ Fullsize - Radial Flux - Stock Fisher & Paykel ~ Weight, The stock weight of rotor and stator is approximately 4.518Kg [10.0 lbs].

To increase the depth of this motor by 50% will result in a new weight of slightly less than 1.5 x 4.518 = 6.78 Kg [15.0 lbs]. This is an increase of 5lbs per motor plus, a miscellaneous increase of +/- 1lb. This means an increase of the crafts weight by approximately 12 lbs.

Megaflux:

The following is a comparison of the Megaflux motors; MF0310025C and MF0310050C

The weight comparison | 15.92 lb. | 30.46 lb. | ratio is 1:1

The speed comparison |775 RRPM | 610 RRPM |ratio is 1.27:1

The torque comparison | 29 lb-ft | 60 lb-ft | ratio is 1:1

The power comparison | 4.12 hp | 6.96 hp | ratio is 1:1.68

Conclusion: Increasing the depth is not an ideal way to increase the power. However, increasing the diameter is probably not any better.

For the same weight the MF0410025C looks better than the MF0310050C.

This implies that increasing the diameter of the motor might be better than increasing it's thickness. Perhaps by implementing parallel wiring.

Coil (pole) Count re: RPM and Torque ~ December 30, 2010:

The F & P is /was produced with 42 coils and 36 coils.

The 42-coil version is the older one.

The 42-coil has a 14:1 electrical to mechanical ratio.

The 36-coil has a 12:1 electrical to mechanical ratio.

Does this mean that the 42-coil will run at approximately 0.858 the speed of the 36 coil, and with proportionally more torque?

The following is an attempt to answer the above question.

Megaflux Motor: - Model:	MF0150	MF0210	MF0310
Poles:	24	32	48
Torque- Cont. stall: (lb-ft)	2.5 - 20.3	6.4 -61.7	15.1 -148.9
Speed - No load: (RPM)	860 - 2663	689 - 1884	235 - 1274
Diameter - Air Gap: ⁽¹⁾ ⁺/_-(in)	4.4	6.7	9.9
______________________________________________________________________________
Relative Torque to Speed: ⁽²⁾	11.4 / 1761.5 = 0.0065	34.05 / 1286.5 = 0.0265	82.0 / 754.5 = 0.1087
Relative Torque to Poles: ⁽³⁾	11.4 / 24 = 0.475	34.05 / 32 = 1.064	82.0 / 48 = 1.708

The diameter of the F&P air gap is ⁺/_-9.6"

Midrange torque /mid speed.

Midrange torque.

Consideration re Producing a Slower Turning F&P with Higher Torque:

Coils:		Coils:	Airgap Dia:	Weight:
36	/ 3-phase / Duplicity =	6	10"	10.0 lbs
42	/ 3-phase / Duplicity =	7	11.67"	11.67 lbs
48 ^{(1) (2)}	/ 3-phase / Duplicity =	8	13.33"	13.33 lbs
54⁽¹⁾	/ 3-phase / Duplicity =	9	15"	15 lbs

The extra 6.66 or 10 lbs might be well worthwhile if it results in a more efficient motor, running slower and cooler with a larger disk area and/or greater angle of attack.

The 48 coils provide the opportunity to use 4-phase, except that the arrangement of the magnets will have to be changed. See; DESIGN: Electrotor-SloMo - Motor - Axial Flux - Overview - 4-phase for SloMoCo (and Bilateral?) ~ Idea for 4-phase:

Cooling:

See; Access Database - Motor - Thermal

See OTHER: Electrical - Motor - Cooling. Section Cooling of Rotor on Outrunner:, Without Halbach Array:

Efficiency:

August 19, 2010

Tests done with the prop on;

Wire 24 AWG:

Efficiency: Record 16 [Wiring 4P*3S] [80V] is 73%, and Record 18 [Wiring 4P*3S] [69V] is 77 %

Wire 14 AWG:

Efficiency: Record 21 [Wiring 1P*12S] [70V] is 41%, and Record 23 [Wiring 6P*2S] [70V] is 41 %

This difference in efficency is signifficant when considering the necessary battery weight for a given time of flight.

It is even more significant if the lower effecicency results in higher heat and the higher heat reduces the efficiency even further.

Perhaps the the large difference in the efficiencies is that the power of PMs have not been increased, at all let alone proportionately.

Controller Information:

General:

For improvements to motor see 'Radial Flux Motors' 3-ring binder, and specifically the five chapter 'Brushless 101' collection of papers.
See 'Control Motor' 3-ring binder.

Power Section:

The Power Section of the Controller will probably be 2 of this; Electrotor-SloMo - Control - ESC - Three-phase - Power Stage - Overview

Electronic Section: The Low voltage control section

Associated Pages:

BUY ~ Motor ~ Fullsize - Radial Flux - Stock Fisher & Paykel

MAKE ~ Electrotor-SloMo ~ Control Electric - Power Circuit - Outrunner Project

OTHER: Electrical - Motor - Dynamometer I:

Last Revised: December 22, 2011