converting 1/2" drill motor to sprocket system

[JimB006]

I have a 1/2" 450RPM 4.5amp drill motor that I use to raise and lower my antenna tower. The drill motor drive a 50:1 gear winch. I want to make a sprocket system using a 115volt frame motor. Any suggestions on motor size and sprocket size would be appreciated. The torque required, which I don't know, is about the max for this 1/2" drill motor.

Thanks,
Jim

 

[3DDave]

You need to look at the power required - Force times velocity multiplied by decent conversions depending on going to Watts or Horsepower. Check units carefully and compare them with the rated power on the drill motor if the label is still in place. This would give the same performance as you currently have. More power would operate it faster, less power would require it to go slower.

Or you could affix an adapter to the gear winch and measure the torque the gear winch requires; presumably you are going to still use the gear winch. Any reason you prefer a sprocket and chain?

Once you know the torque the winch requires and power (speed of operation) you can pick a motor and matching gear ratio. They are tied together so it's a chicken and egg problem. The higher the speed for a given power, the greater the gear reduction will be required, but also the reaction forces on the motor will be lower.

You might noodle over some choices at

https://www.grainger.com/category/general-purpose-ac-motors/motors/ecatalog/N-ls1

Umm - what are you planning on doing to reverse the operation? Some motors are reversible but it requires a separate control on single phase.

 

[JimB006]

The drill motor is rated at 450rpm, 4.5amps. I thought a chain and spocket will eliminate any slippage. To measure the torque I will have to lower the tower and measure the torque with a torque wrench on the gear winch. But I will have to wait until the spring for the weather to change. I plan on using a reverse switch for the single phase motor. I have a couple 1/2 hp and one 3/4 hp. Not sure of the 3/4 hp is reverseable.

Thanks for your time. I'll update if I can find more info that you ask for.

Jim

 

[dvd]

Based on Power = Amps x volts = 4.5 amps x 120 volts = 540 Watts ~ 0.72 HP

At 450 RPM the output torque of the drillmotor is T = HP x 63025 / 450 RPM = 101.4 lb-in

Based on an assumed 1750 RPM motor, it looks like a US Tsubaki RS25 (0.25 inch pitch) 20 tooth driver and 80 tooth driven sprocket would provide a little better than 1.5 service factor and provide a 4:1 reduction to match the drillmotor output speed. Caution to know the overhung load rating of the motor you select. You might overload the bearings with a chain drive, especially if over-tensioned.