Frank L. Kohlerman Jr., an electrical engineer for Baltimore Gas & Electric Co. for 41 years and a military reservist until age 60, died May 3 at his home on Woodlawn Road in Roland Park from complications from arthritis. He was 77.

Mr. Kohlerman directed BG&E;'s Intersystem Power Utilization Bureau, which coordinated the buying and selling of power among BG&E; and other power systems in the Northeast.

Born in Baltimore, he graduated from Forest Park High School in 1931 and received a degree in engineering in 1935 from the Johns Hopkins University.

Mr. Kohlerman served in the U.S. Air Force during World War II. A communications expert, he taught officer candidate school in the Signal Corps at Fort Monmouth, N.J., from 1941 to 1942.

He graduated from the Command and General Staff School in Fort Leavenworth, Kan., in 1943. Mr. Kohlerman entered the Air Force and was stationed at Fort Monmouth until 1946. He retired from the Air Force with the rank of lieutenant colonel.

Mr. Kohlerman is survived by his wife, Beth Kohlerman; a son, Charles Edward Kohlerman of Baltimore; a daughter, Elizabeth K. Winship of Baltimore; and two granddaughters.