drkrem
off to a rocking start
Member since November 2021
Posts: 4
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Post by drkrem on Dec 17, 2021 10:36:37 GMT -5
Recently acquired a 100w DC electric scooter motor for 5$ (model ZYT68100-24V), if I understand correctly it is roughly 1/8hp. Will this be enough to power a 8" flat lap?
Already have a treadmill motor I was planning on using but it is significantly overpowered which I am fine with, just would like to save it for a more appropriate application if possible.
I have a bunch of 1/4 hp 1725rpm AC motors but I need variable speeeeed.
Any advice is appreciated, thank you.
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NDK
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Member since January 2009
Posts: 9,440
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Post by NDK on Dec 17, 2021 11:31:19 GMT -5
1/8 hp may not be enough power, I'll let the experts chime in on that.
I thought I was going to want a variable speed when I built my flat lap as well. Had a reg ac motor (I believe 1/3hp) laying around so I used that & never switched it. In fact I built another similar piece of equipment for polishing with. Have a 2 speed motor on that and have never switched that either LoL
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jamesp
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Member since October 2012
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Post by jamesp on Dec 17, 2021 12:43:24 GMT -5
I built a flap lap using a 1/4 1725. It has plenty of power with the pulley ratio turning lap about 800 rpm. Keep in mind the center section has much slower linear speed. I too never found a need for varying speed after that. DC motors can generate a lot of power but it depends on the amount of voltage(speed) and current(torque) you feed it. some photos if helpful www.flickr.com/photos/67205364@N06/sets/72157696891131845
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Post by Rockoonz on Dec 17, 2021 12:48:28 GMT -5
Start up torque and lower speed torque is what you're looking for. In a scooter I would think there is torque. Problem is your power supply, the charger won't supply anywhere near the current you need to run it, so you will have to use a battery near the same voltage or a good DC power supply. If you can run bigger wires to the motor you may see some improvement. Directly mounting your lap base on the motor is a mistake that a lot of people make, a belt drive with pulleys to reduce the motors top speed to your highest desired speed will multiply the torque, provide better speed control, keep excessive weight off the motor bearings, and make it possible to isolate the motor from the water better. 2 speed fan motors like the ones for swamp coolers are definitely a good choice too, with a belt drive. The fastest you will want to run a lap is about 1000 RPM, over that and centifugal force spins the water off the disc and it wears quickly. Most facetors run about 900 RPM max speed.
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drkrem
off to a rocking start
Member since November 2021
Posts: 4
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Post by drkrem on Dec 17, 2021 12:59:49 GMT -5
To be honest I only want variable speed because both me and my girlfriend use the machine and we have different speed preferences. Switching pulleys is getting old lol
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drkrem
off to a rocking start
Member since November 2021
Posts: 4
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Post by drkrem on Dec 17, 2021 13:05:25 GMT -5
Start up torque and lower speed torque is what you're looking for. In a scooter I would think there is torque. Problem is your power supply, the charger won't supply anywhere near the current you need to run it, so you will have to use a battery near the same voltage or a good DC power supply. If you can run bigger wires to the motor you may see some improvement. Directly mounting your lap base on the motor is a mistake that a lot of people make, a belt drive with pulleys to reduce the motors top speed to your highest desired speed will multiply the torque, provide better speed control, keep excessive weight off the motor bearings, and make it possible to isolate the motor from the water better. 2 speed fan motors like the ones for swamp coolers are definitely a good choice too, with a belt drive. The fastest you will want to run a lap is about 1000 RPM, over that and centifugal force spins the water off the disc and it wears quickly. Most facetors run about 900 RPM max speed. Thanks for the input, that seems like more trouble than its worth, especially with water involed. I will rig up my OP treadmill motor until I can find a better alternative.
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drkrem
off to a rocking start
Member since November 2021
Posts: 4
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Post by drkrem on Dec 17, 2021 13:10:54 GMT -5
I built a flap lap using a 1/4 1725. It has plenty of power with the pulley ratio turning lap about 800 rpm. Keep in mind the center section has much slower linear speed. I too never found a need for varying speed after that. DC motors can generate a lot of power but it depends on the amount of voltage(speed) and current(torque) you feed it. some photos if helpful www.flickr.com/photos/67205364@N06/sets/72157696891131845I agree with you, and that is what Ive always used but multiple people use the machine and I'm tired of switching pulleys. Also think its just a cool feature to have.
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jamesp
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Member since October 2012
Posts: 36,562
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Post by jamesp on Dec 17, 2021 13:19:11 GMT -5
I built a flap lap using a 1/4 1725. It has plenty of power with the pulley ratio turning lap about 800 rpm. Keep in mind the center section has much slower linear speed. I too never found a need for varying speed after that. DC motors can generate a lot of power but it depends on the amount of voltage(speed) and current(torque) you feed it. some photos if helpful www.flickr.com/photos/67205364@N06/sets/72157696891131845I agree with you, and that is what Ive always used but multiple people use the machine and I'm tired of switching pulleys. Also think its just a cool feature to have. Higher speed would be a choice in my situation but heat on brazed diamonds may happen causing premature diamond loss and water sling may become excessive. For the best finishing abrasive steps slow with low vibration is important to avoid rough grind spots.
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Post by Rockoonz on Dec 17, 2021 17:09:55 GMT -5
drkrem I don't know what you have in the way of budget or fabricating tools, but another option is a stepper motor for a sewing machine. I got one with controller from Amazon for my old faceting machine. "Consew" is the brand. The final steps and a build thread should happen pretty soon, it is definitely a great upgrade, possibly more complex than you're looking for right now, but enough torque to resist all attempts to stop it from too slow to use up to way too fast is pretty neat.
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