Reel to Reel

These motors were taken out of old Mainframe 1/2 inch reel to reel tape drives. Typical each reel of tape had 2400 ft of tape. A lot of slow motion starting and stopping was done. Because of the relatively low price and ease of availability I decided to test a few of these motors to determine their workability as a generator for hand crank or bicycle generator use.

My current tests used a 1/3 hp 1725 RPM 115 Volt AC motor to turn the PM DC motor as a generator. A short section of garden hose with hose clamps were used as a flex shaft to couple both AC Motor and generator together. An oscilloscope, laser pointer, and solar cell was used to measure the RPM. Digital voltmeters were used to measure amperage and current. The motor was taped to a board using clear 2" wide tape.

For rough order power capabilities of a PM DC motor, do a resistance test. If one uses an Ohmmeter across the leads, the brush resistance will make it higher than it really is. The best way is to clamp the shaft so that it doesn't rotate and measure the current with some amount of voltage applied say 12-Volts DC. Using ohms law the resistance then is voltage divided by current. I now have 4 different types of these tape drive motors.

Offered by Mike.