motor wattage

[REDWOOD]

I might convert my hand extractor to an electric one and need to know if the set up I'm thinking about will work.
I have been given an electric golf trolly axle with gear box with a maximum output shaft speed of 150 rmp and a 150w 12v motor. I plan to mount it with a 3.5:1 gear on the end so giving a top speed of 525rpm

I just need to know if this motor is powerful enough to drive 12 frames at that speed
I will be running it through a speed controller.

 

[Fusion_power]

1. Tangential extractors need to run about 300 rpm max. Radials can run up to about 500. Use a variable speed motor to select the best speed. Most AC motors are not variable speed. Most DC motors are variable, but may have torque mismatch with the load.

2. 746 watts equals 1 horsepower. The motor you have is about 1/5 horsepower. It would spin a 2 frame extractor but probably not a 4 frame and will be seriously under-powered for most 9 frame or larger radial extractors. I use a 1/2 hp AC motor to pull a 4 frame tangential extractor with pulley reduction to get max speed to about 300 rpm.

3. There is a caveat re the motor power. Is it a series wound motor like most hand drill motors? If so, then it develops much more torque at low speeds and therefore may still work for an extractor. The problem with this is that sustained heavy loads that force the motor to run at slow speeds may burn out the motor windings.

 

[oliver90owner]

Most 9 frame radials have an 80W variable speed motor and top speed would be around 300rpm at the driven shaft.

look at your present gearing. Likely 3 1/2:1 and then see how fast you normally turn the handle. Remember that a motorised extractor can be run for longer than it takes your arm to tire! Over-gearing it would be counter productive.

 

[REDWOOD]

Thanks for the replies

 

[Gilberdyke John]

We used squirrel cage motors with variable frequency inverters to drive monopumps but at the lower end of the speed range motor temperature became problematic. The shaft mounted cooling fan performance fell off (iirc by the cube of the speed) and the motor overheated. Larger units which ran slow for extended periods had separate cooling provided.