Will it harm an electric motor to run it at 3600 rpms without plugging it in?

[Michael64]

I have a design to run a 10000 watt generator with a gas engine holding the rpms at 3600 rpms.
With pulleys and a clutch (like a lawnmower deck) I can engage the generator.
Another clutch set-up will run from a 7.5 horse electric motor to the generator.
The electric motor is plugged in to a switched outlet.
The gas motor will run the generator powering the outlet for the electric motor.
Can I switch the electric motor on, engage the clutch, and then disengage the clutch from the gas motor.
The electric motor will be running with no load until I can engage the clutch, will that harm the electric motor?

 

[itsmoked]

Why are you running a generator with a motor? You realize a 10kW generator needs about 20HP? Is this over unity nonsense?


Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

Running a 1000 Watt generator from a 7.5 HP motor may be a little under-kill.
If you are going to start the motor with one power source (the switched outlet) and then disconnect it and rapidly connect to another source (the generator) you may have issues when you connect to the generator. If the phase angle of the generator output does not agree with the phase angle of the back EMF of the motor you may experience both current and torque transients.
If you are going to run the generator from the motor from the generator from the motor etc., the concept falls into a category known as "Over Unity". Over unity devices are not patentable.
Over unity devices are a serious violation of the law of conservation of energy.
Good luck.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Skogsgurra]

Whatever you are trying to do, idling at 3600 RPM is your least problem...

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[LionelHutz]

Your title and your question text ask two different questions and the answer to both is no.

The gas motor will run the generator powering the outlet for the electric motor.

Good luck with that arrangement.

 

[jraef]

You are not the first, nor will you be the last, person to ponder the concept of running a motor, to run a generator, to run the motor. The concept goes back to the earliest days of electric motors and generators, in fact really back before that to the earliest ideas about perpetual motion. The laws of physics will smack you up the side of your head with the "billy club of thermodynamics" and place you in the physics clinker, the fine will be whatever it cost you to run this experiment.

But by all means, feel free to try it. It's your money, your time, your head so it can be your lesson. Report your findings back here and we will explain to you what happened after you observe it. There may be some derision and ridicule involved, but hey, it's the Internet!


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[waross]

You said it better than I, Jeff.
A masterful blending of tough love and restraint.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[cranky108]

This sounds like a UPS type of case. A Motor-generator type of case has been used before, with the inclusion of a flywheel on the shaft. But between any two moving, or non-energized and moving systems you will need a clutch.

Turing a motor without having it energized is not a problem, as the fan is normally attached to the shaft. But spinning the fan and bearings is sort of wasteful losses. But when you energize the spinning motor, the system will change speed, and need to adjust, which is why you need a clutch to prevent over driving the engine, and sudden speed jumps while the motor adjusts for sudden phasing.