So if I have an average rpm of 100 rpm and the rates torque is .45 kgcm, does that mean this has a power output of 4000 Watts?

I know this answer is coming to you 3 years too late - and you probably figured this all out. Just in case - here is how you can calculate the power from the torque and RPM. A couple of quick notes: Torque is force times length - kg is not a force but a mass. If the "torque" is given in kg*cm - then this is not a proper torque number. It should be in Newton*cm. Newton is the unit for force and kg for mass. The force a mass experiences here on earth is the mass multiplied by the earth's acceleration of the mass in the earth's gravity. This acceleration is 9.81 m/s/s (meters per seconds squared). This unit is the same as N/kg (not that readily visible - but for now we'll just accept that as correct). Now we can calculate the proper torque by multiplying the two numbers: 4.5kg*cm * 9.81 N/kg = 44.2 N*cm. Power is work done per time - work, energy and torque are identical units of measure - force times length - the continuously delivered torque is the same as the work done by the motor. However, for the power to be correct we have to express work in N*m (SI units) - not N*cm. So we have translate N*cm into N*m. 100 cm = 1 m or 1cm = 0.01 m. We can just simply replace the cm with 0.01m and well get the torque (work) in N*m - 4.42N* 0.01m = 0.442 N*m. Next: power is Nm/s in SI units - that means we have to express 100 rpm in rps (revolutions per second = rev/sec). 1 min = 60 seconds. 100 rpm = 100 revs per 60 secs = 100/60 rps = 1.7 rps. Now we can calculate the power in N*m/s: 0.442N*m * 1.7 rps = 0.74N * m / s = 0.74W of mechanical power - which is even less power. Of course that's only correct if the 4.5kgcm number is correct for the motor. Some of the suggestions were to use the electrical power of the motor to estimate the mechanical output power. That too is a legit approach - however, that power setting given must be under the same conditions for which the mechanical output was given. E.g. the motor must run at 100 rpm and deliver the torque given - only then the current draw by the motor and the voltage accross the motor can be used to calculate the approximate mechanical power. For example - if the motor draws 1A at 12V when stalled out (motor is slowed down to a stop), then this is not the same condition as running the motor at 100 rpm. Sometimes the specifications given for those products can be a bit questionable.

Can this fit into a 1/4” metal rod? With a shaft collar or something?

If you are widening a coupler and you can, use a drill press or milling machine. Be sure the setup is as rigid as possible. Use a "reamer" 1/4" in diameter if you can get one. They are special purpose tooling but get used all the time for this exact job. They cost a few dollars. Use very low speed or even turn the chuck by hand. Do not use a hand dill at full speed with a twist bit. I would rather use 400 grit sand paper or fine abrasive padding than any sort of standard drill and bit.

How many rotations does this motor make a minute

As stated on the label.... 100 revolutions per minute (rpm)

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Reviews

G**R

Good little motor

Good quality geared motor that works a treat for my 3D filament spool rewinder when used in conjunction with a speed controller PCB, and 12V power supply. The item is well assembled, therefore it will hopefully keep going for a long time.

29.10.2025

A**R

Great construction quality.

Smooth operation and sturdy construction has made this a firm favourite for my robotics work. Love the quality. One less thing to worry about. Good value for money.

1.03.2025

O**N

Good motor

Very useful and functional motor. Arrived on time and are very versatile. They do however require a very large space in a project as it is a fairly large motor about 750mm

8.12.2024

D**A

Good build quality motor works a treat

Good build quality geared motor works a treat for my 3D filament spool rewinder when used in conjuncyion with a speed controller. Item seems to be well assembled and for such a fast motor the sound is fine.

30.12.2023

T**K

does what it says

Another project

14.01.2026

P**G

Compact and well made

Used for a vintage car heater.

15.07.2024

R**P

Electric motor

Needed this for a small project, works well

7.01.2024

M**S

Nice motor, good size.

Unfortunately it stalls on low speed, hence to fast for my application

2.06.2023

R**.

Perfetto per fare aprire e chiudere una porta da esterno con un telecomando e messo fine corsa in apertura e chiusura, lo consiglio vivamente .

27.05.2025

A**A

The motor arrived quickly in good condition . It is very quite and works well . The only issue I had was I was not able to lower the speed with a motor speed controller. Over all it is worth the money

16.10.2022

C**.

Bon moteur bonne finition fait pour des utilisations de comptage guidage. Je l'utilise en bobineuse pour micro et sa fonctionne très bien.

28.05.2025

B**P

works as expected

18.01.2026

T**M

Works perfectly! Much more powerful than I expected.

13.11.2025

ASIN	B072R5G5GR
Batteries Required?	No
Batteries included?	No
Best Sellers Rank	10,236 in Business, Industry & Science ( See Top 100 in Business, Industry & Science ) 2 in Gearboxes, Gearheads & Speed Reducers
Colour	550 RPM
Customer Reviews	4.5 4.5 out of 5 stars (1,523)
Date First Available	15 Jun. 2017
Horsepower	550 Watts
Item Package Quantity	1
Item Weight	200 g
Item model number	Greartisan
Manufacturer	Greartisan
Material	Metal
Part Number	Greartisan
Product Dimensions	3.7 x 3.7 x 3.7 cm; 200 g
Size	12 Volt
Speed	550 RPM
Voltage	12 Volts

Greartisan DC 12V 550RPM Gear Motor High Torque Electric Micro Speed Reduction Geared Motor Centric Output Shaft 37mm Diameter Gearbox

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