Motor has high starting torque and high running speeds. Control system consists of Hall effect generator/resolver and associated electronic amplifiers and switches. Motor operation is described

Auclair, G. F.

Hertzendorf, B. H.

Manteuffel, E. W.

English

NASA Technical Reports Server

12 MV/V
—9V
280 A/V 1. 
H°209
Ft- Lb/Amp 
For Each Section 
-	 1 Hall	 60 MV Vhl	
+9V
+33V	 +5V 
+5V	 +3 3V r 
Motolifier I Generator	 I •
- - - - - - Amp	 No. 1 
r 
ml N1.
SummingI I	 Pulse Per 
Amplifier h Morjulatorl Bridge
I	 I Il 
December 1971	 Brief 71-10530 
S NASA TECH BRIEF 
Marshall Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a aubscription basis from the National Technical Information 
Service, Springfield; Virginia 22151. Requests for individual copies or questions relating to the. Tech Brief program may 
be directed to the Technology .
 Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Brushless DC Motor with Dual Windings 
A novel, split-winding dc motor has both high start-
ing torque and high running speeds. The motor's dual 
windings may be connected in series to produce high 
torque at low speeds (520 rpm with 6.70 ft-lbs torque), 
or in parallel to give low torque at high speeds (1040 
rpm with 3.35 ft-lbs torque).
leads the rotor field by 90°. The motor torque, which 
tends to align the two fields, remains the same regard-
less of rotor position. Thus, the control system re-
places the commutator in a conventional dc motor. 
The figure shows a block diagram of the motor and 
control system. The dc-dc converter, connected to a 
—9V 
+ 9V 
Vini
1.0 V/V 
+9V
dc-dc 
Converter 
+5V1	 FT 
Integrator
Select 
Resistor 
Triangularf 2.0 Volt 
Wave	 Peak to Peak
1.34 Ft-Lb/Volt (Series) 
0.67 Ft-Lb/Volt (Parallel) 
I	 - 
L ---- \j LiJ 
Hall	 Triangular	 Current 
No. 2	 0	 Shunt 
Generator	 Wave	 Feedback	 Main 
Motor 
- Vh2
	 Amplifier No. 2  
--J 
Resolver 
Rotor 
The motor control system consists of a Hall-effect 
generator/resolver and associated electronic ampli-
fiers and switches. The system controls the power sup-
plied to the motor's stator windings, causing the stator 
to produce a magnetic field that varies with the posi-
tion of the resolver rotor. The resolver rotor is 
mechanically coupled to the main permanent-magnet 
rotor, and is aligned so that the stator field constantly
+33 Vdc external power supply, generates the low 
voltage supplies required for operating integrated cir-
cuits. It also produces a 5 kHz square wave, which is 
integrated to provide a triangular waveform for the 
pulse width modulator. 
The motor amplifiers increase the Hall voltages, 
V h I and Vh2, to drive the two motor windings with 
currents 
'ml and lm2. The motor currents are pro-
-	 I ClrStIIlSlCSI osc dcal 
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	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	
will be free from privately owned-rights. 
https://ntrs.nasa.gov/search.jsp?R=19710000521 2020-03-17T02:27:02+00:00Z
portional to the sine and cosine of the motor shaft 
angle. Each motor amplifier consists of a power bridge 
circuit, a pulse width modulator, a summing amplifier 
and shunts. The pulse width modulator converts dc to 
10 kHz pulse trains which are fed to two drivers. The 
drivers, high voltage gates, operate the transistor 
switches of the power bridge. Shunts in the bridge cir-
cuit develop a feedback voltage which is proportional 
to motor current. 
Note: 
The following documentation may be obtained 
from
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.95) 
Reference: 
NASA CR-102675 (N70-28243), Final Report, 
Brushless DC Motor and Controller
Patent status: 
No patent action is contemplated by NASA. 
Source: E. W. Manteuffel, G. F. Auclair, and
B. H. Hertzendorf of
General Electric Co.
under contract to
Marshall Space Flight Center
(MFS-21290)
. 
. 
Brief 71-10530	 Category 02


Brushless DC motor with dual windings

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