Electric motor runs but lacks power.

Mark Harvey · 12-26-2010, 05:12 PM

The motor is from a portable cement mixer, second hand, so may not be the original motor, The motor is a Wagner Leland, type SP AKT6, Model F7 939NH. 1725 RPM, 115v, 5.0 Amp, Rating continous. It ran when I first got it but could not handle the load once I filled the Drum. The pulley ratio looks fine, I think the motor needs some new life. Questions, Should this size motor handle the job? If it should, what need to be done to regain the power? Should it be rebuilt or replaced?
If it is the wrong size, what is recommended?
Thanks

AllanJ · 12-26-2010, 06:51 PM

You may want to do some tests.

Measure the voltage at the motor (as opposed to at the receptacle (outlet). The power cord could be defective causing a severe voltage drop. You may also (carefully) feel every inch of the power cord for unusual warmth which is abnormal and the hot spot is where a defect is in the cord (or plug).

I am guessing that a small cement mixer drum should rotate about 20 rpm or 3 seconds per revolution. If it goes much faster when empty then the pulley ratio might be unfavorable for the motor.

5 amps at 120 volts is a little over 3/4 horsepower.

brric · 12-26-2010, 07:10 PM

Quote:

Originally Posted by AllanJ

You may want to do some tests.

Measure the voltage at the motor (as opposed to at the receptacle (outlet). The power cord could be defective causing a severe voltage drop. You may also (carefully) feel every inch of the power cord for unusual warmth which is abnormal and the hot spot is where a defect is in the cord (or plug).

I am guessing that a small cement mixer drum should rotate about 20 rpm or 3 seconds per revolution. If it goes much faster when empty then the pulley ratio might be unfavorable for the motor.

5 amps at 120 volts is a little over 3/4 horsepower.

Sorry, it's closer to 1/4 or 1/3 horsepower.

frenchelectrican · 12-26-2010, 11:27 PM

That is wrong motor for this useage and you will need at least minuim of 1/2 HP or larger most common is 3/4 HP and watch the pulley ratio as someone mention before.

The motor you have there is either 1/4 or 1/3 HP the most and it will stall very easy with the load you throw in there.

Merci.
Marc

Mark Harvey · 12-27-2010, 12:26 PM

Thanks to all. It sounds as if I should just get a new motor ... 3/4 horse. The pully ratio can control the speed but a stall is a stall and doesn't make for a good tool. Thanks again. Any sugested brands or does it reall matter?

12-26-2010, 05:12 PM	#1
Mark Harvey Solutions (handyman) Join Date: Apr 2009 Location: Central Alberta Canada Posts: 299	Electric motor runs but lacks power. The motor is from a portable cement mixer, second hand, so may not be the original motor, The motor is a Wagner Leland, type SP AKT6, Model F7 939NH. 1725 RPM, 115v, 5.0 Amp, Rating continous. It ran when I first got it but could not handle the load once I filled the Drum. The pulley ratio looks fine, I think the motor needs some new life. Questions, Should this size motor handle the job? If it should, what need to be done to regain the power? Should it be rebuilt or replaced? If it is the wrong size, what is recommended? Thanks

12-26-2010, 06:51 PM	#2
AllanJ Member Join Date: Nov 2007 Location: Nashua, NH, USA Posts: 6,775	Electric motor runs but lacks power. You may want to do some tests. Measure the voltage at the motor (as opposed to at the receptacle (outlet). The power cord could be defective causing a severe voltage drop. You may also (carefully) feel every inch of the power cord for unusual warmth which is abnormal and the hot spot is where a defect is in the cord (or plug). I am guessing that a small cement mixer drum should rotate about 20 rpm or 3 seconds per revolution. If it goes much faster when empty then the pulley ratio might be unfavorable for the motor. 5 amps at 120 volts is a little over 3/4 horsepower. __________________ The average homeowner who lost his house in the Oklahoma tornadoes should move for good and not rebuild. Too much complexity watchdogging the contractor. Too much a chance to be defrauded.

12-26-2010, 11:27 PM	#4
frenchelectrican " Euro " electrician Join Date: Apr 2006 Location: WI & France { in France for now } Posts: 5,104	Electric motor runs but lacks power. That is wrong motor for this useage and you will need at least minuim of 1/2 HP or larger most common is 3/4 HP and watch the pulley ratio as someone mention before. The motor you have there is either 1/4 or 1/3 HP the most and it will stall very easy with the load you throw in there. Merci. Marc __________________ The answer will be based on NEC ( National Electrical code ) or CEC ( Cananda Electrical code ) or ECF ( Electrique Code France )

12-27-2010, 12:26 PM	#5
Mark Harvey Solutions (handyman) Join Date: Apr 2009 Location: Central Alberta Canada Posts: 299	Electric motor runs but lacks power. Thanks to all. It sounds as if I should just get a new motor ... 3/4 horse. The pully ratio can control the speed but a stall is a stall and doesn't make for a good tool. Thanks again. Any sugested brands or does it reall matter?

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Electric motor runs but lacks power.