Problem: Electric motor:

A PM motor does not have a field winding on the stator frame, instead relying on PMs to provide the magnetic field against which the rotor field interacts to produce torque. Compensating windings in series with the armature may be used on large motors to improve commutation under load. Because this field is fixed, it cannot be adjusted for speed control. PM fields (stators) are convenient in miniature motors to eliminate the power consumption of the field winding. Most larger DC motors are of the "dynamo" type, which have stator windings. Historically, PMs could not be made to retain high flux if they were disassembled; field windings were more practical to obtain the needed amount of flux. However, large PMs are costly, as well as dangerous and difficult to assemble; this favors wound fields for large machines.

What do field windings provide?
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A: flux

Problem: According to eastern homeland theory, prior to becoming known to the Roman world, Slavic-speaking tribes were part of the many multi-ethnic confederacies of Eurasia such as the Sarmatian, Hun and Gothic empires. The Slavs emerged from obscurity when the westward movement of Germans in the 5th and 6th centuries CE (thought to be in conjunction with the movement of peoples from Siberia and Eastern Europe: Huns, and later Avars and Bulgars) started the great migration of the Slavs, who settled the lands abandoned by Germanic tribes fleeing the Huns and their allies: westward into the country between the Oder and the Elbe-Saale line; southward into Bohemia, Moravia, much of present-day Austria, the Pannonian plain and the Balkans; and northward along the upper Dnieper river. Perhaps some Slavs migrated with the movement of the Vandals to Iberia and north Africa.
Who was fleeing from the Germans?
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Answer: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Houston is the seat of the internationally renowned Texas Medical Center, which contains the world's largest concentration of research and healthcare institutions. All 49 member institutions of the Texas Medical Center are non-profit organizations. They provide patient and preventive care, research, education, and local, national, and international community well-being. Employing more than 73,600 people, institutions at the medical center include 13 hospitals and two specialty institutions, two medical schools, four nursing schools, and schools of dentistry, public health, pharmacy, and virtually all health-related careers. It is where one of the firstand still the largestair emergency service, Life Flight, was created, and a very successful inter-institutional transplant program was developed. More heart surgeries are performed at the Texas Medical Center than anywhere else in the world.
How many hospitals are outside of the Medical Center group of organizations?
A: unanswerable

Context and question: Some of the second-generation renewables, such as wind power, have high potential and have already realised relatively low production costs. Global wind power installations increased by 35,800 MW in 2010, bringing total installed capacity up to 194,400 MW, a 22.5% increase on the 158,700 MW installed at the end of 2009. The increase for 2010 represents investments totalling 47.3 billion (US$65 billion) and for the first time more than half of all new wind power was added outside of the traditional markets of Europe and North America, mainly driven, by the continuing boom in China which accounted for nearly half of all of the installations at 16,500 MW. China now has 42,300 MW of wind power installed. Wind power accounts for approximately 19% of electricity generated in Denmark, 9% in Spain and Portugal, and 6% in Germany and the Republic of Ireland. In Australian state of South Australia wind power, championed by Premier Mike Rann (20022011), now comprises 26% of the state's electricity generation, edging out coal fired power. At the end of 2011 South Australia, with 7.2% of Australia's population, had 54%of the nation's installed wind power capacity. Wind power's share of worldwide electricity usage at the end of 2014 was 3.1%. These are some of the largest wind farms in the world:
In Spain, wind power doesn't account for what percentage of electricity generated?
Answer: unanswerable

Question: Maria Deraismes was initiated into Freemasonry in 1882, then resigned to allow her lodge to rejoin their Grand Lodge. Having failed to achieve acceptance from any masonic governing body, she and Georges Martin started a mixed masonic lodge that actually worked masonic ritual. Annie Besant spread the phenomenon to the English speaking world. Disagreements over ritual led to the formation of exclusively female bodies of Freemasons in England, which spread to other countries. Meanwhile, the French had re-invented Adoption as an all-female lodge in 1901, only to cast it aside again in 1935. The lodges, however, continued to meet, which gave rise, in 1959, to a body of women practising continental Freemasonry.
Is there an answer to this question: What year was an all-animal masonic lodge created?

Answer: unanswerable

Question: Industries slowly brought the city and its inhabitants back to a renewed vitality and jobs attracted new residents. As the city's commerce improved, residents worked to restore or create community institutions. In 1865, the Avery Normal Institute was established by the American Missionary Association as the first free secondary school for Charleston's African American population. General William T. Sherman lent his support to the conversion of the United States Arsenal into the Porter Military Academy, an educational facility for former soldiers and boys left orphaned or destitute by the war. Porter Military Academy later joined with Gaud School and is now a university-preparatory school, Porter-Gaud School.
Is there an answer to this question: Who never attended the Avery Normal Institute?

Answer:
unanswerable