Montgomery County police officials recently announced changes in six top positions, including the naming of Maj. Frederick W. Chaney, formerly in charge of the management services bureau, as chief of field services, third in command on the force. Chaney will be in charge of about 70 percent of the police force. Others who were promoted:Maj. Robert B. Renfrew, district commander of the Germantown station, assigned to head the management services bureau. Capt. Joseph R. Hancock, internal affairs director, assigned as Silver Spring district commander. Capt. Owen Bromley, Silver Spring district commander, assigned district commander of the Germantown station. Capt. James A. Taylor, chief for the special investigative division, to head internal affairs. Lt. Ronald A. Ricucci, head of narcotics, now will head the special investigative division.

Chaney, who now oversees most day-to-day operations, replaces Maj. O.W. Sweat, who retired Nov. 29 to become chief of protection and security at the National Institutes of Health in Bethesda.

Chaney, 48, who has been in police work for nearly 27 years, said that in his new position he wants to stress courtesy in dealing with the public and providing "the best service we can with the resources we have."

He said that top police officials will meet shortly to set priorities for the new year, discuss problem areas and patrol needs.

"In the past, there was a lot of emphasis" placed on drunk driving cases, Chaney said. "That will continue, but there will also be emphasis on burglaries and robberies, and strategies to reduce them."

Police officers will also be reassigned, Chaney said.

One result of that redeployment, he said, will be to increase the size of the force in the Germantown District, where there has been a steady increase in population and a concurrent increase in calls for service and criminal activity.