I need to design a project around this motor

Wind mill / generator?????

Be sure to have the field powered up when the armature is powered up to avoid over speed. Shunt wound DC motors use the field for speed control and counterintuitively will experience run away speed when the field is not powered. ERS

With a 27 volt 3.5 amp load for the field it would do poorly except in gale winds, a PM field would be more efficient.

Since you suspect it is an aircraft starter motor . . .build an airplane.

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Well it states on its info plate that its an aircraft motor, just trying to figure out what it would be for. IIRC Shunt wound motors where (are?) pretty extensivly used in automotive for starters, so I'm just guessing.

I'm mainly concerned/interested about the time rating. My only guess is that it produces some crazy torque, that could be tempered with current limiting, thus extending the usable time range.

perhaps a motor guru could step in and fill in my very limited knowledge.

Most DC drives have a field current sense circuit and if you get a field loss the circuit will shut down the drive. At zero field current the formulas indicate that the rpm will go to infinity... it won't though, the armature explodes in a big bang long before it reaches anything near infinity...

John

It was probably an electric prop pitch/feathering motor used on , I think, B-36 aircraft. They were probably servo controlled to maintain constant RPM. I had a similar system but much smaller on my E35 Beech Bonanza.

John

Indy Car?

I'm not an expert on electric motors generally, but I've spent a few years dealing with DC motors used in aircraft.

Aircraft starter motors are normally series wound. Yours may be a landing gear motor or flap motor. The limited duty cycle is probably because it has no provision for airflow for cooling. Gear and flap motors operate for very short periods, and do not normally have fans. Since weight is always a concern, they don't have much mass to absorb heat, either.

Shunt wound motors are easy to reverse. Series wound motors are a bit more difficult to reverse. Series wound motors have lots of torque at low rotational speeds when compared to shunt wound motors, but the rotational speed of shunt wound motors is much easier to control. Continuous-duty motors are nearly always shunt-wound or hybrid, and have some provision for cooling. Sometimes cooling air is ducted to the motor from the slipstream, or the motor has a fan, or both. Yours may need a little alteration before it will survive continuous use.

Hmm ... perhaps a prop pitch motor? Used (back in the days of large piston engine propeller planes to change the angle of the prop blades to match the thrust needed to the most efficient RPM for the motors. (They were in the spun aluminum housing on the front of the props in those planes.)

Or -- it could be for adjusting flaps via ballscrew actuators.

Or for raising or lowering the landing gear.

All of those functions would need fairly short run times, and then just let the motor sit there until the whatever needed to be adjusted again.

The flaps would be adjusted for low speed flying close to the ground (just prior to landing or takeoff).

The wheels would only be adjusted just after takeoff or just prior to landing.

Also -- perhaps to retract boarding ramps?

Perhaps to open tail doors for cargo drops?

Lots of things which it *could* be used for. It is just a question of finding the task which matches the HP and torque available from that motor.

I'm not a motor guru, but I can see quite a few things on aircraft which would need a short-run-time motor.

Enjoy, DoN.

I'd guess at about 20lbs, so heavy for its size, but not terribly big (compared to say a 1/2 horse AC motor)

I popped the back off it and it has something that kinda looks like a fan, but without full blades. I'm up for suggestions on how to modify it to get more run time.

I think having to poor lots of work into this will teach me to not buy before thinking. But having a 1 hp motor laying around won't be bad either.

I meant a guru to teach me how to use this thing without burning it out. I'm guessing current limiting will increase the run time proportionately.

I've rethought the high torque thought as the amps seem to be pretty relational to the voltage compared to a more modern 180V 1HP (5.3ish amps at 3 times the voltage)

Your controller varies the field to govern your output, thats what makes this unit attractive for the purpose.

Elevator motors used to position a rack of bombs on a WW-II bomber?

I was thinking more about the ones which set the flaps and trim tabs. They spend most of the flight in one position, and are activated either when just taking off or landing, or when adjusting the trim for neutral flight when the weight changes -- such as a bunch of paratroops exiting the plane. I *think* that the weight of the bomb load tends to be more central, so the balance is not shifted much by dumping them.

Enjoy, DoN.

The last "electrical" airplanes I worked on were B-50's. The flap motors, which drove the flaps up and down through a gearbox and drive shafts through the wings, were just normal 24 VDC motors. For example, the emergency flap motor, which could be disconnected from the flap system and used to power the landing gear in an emergency was exactly the same construction as the landing gear and normal flap motors.

By the way, there were no "elevation motors used to position a rack of bombs on a WW-II bomber". Bruce in Bangkok (brucepaigeatgmaildotcom)

A surplus place was selling motors using that description about 25 years ago. Everything else they advertised was what they said, so I had no reason to doubt it.