# Torque Calculators

## Select Your Type of Torque

TH = 63,024 x ((P x K)/ω)

Torque is required to stop
Motor rotating at
Service Factor
Calculate Torque!
Torque Required

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### Calculating Torque for a Clutch or a Brake Application When the Horsepower is Known

When information about holding torque or load torque is unavailable, the horsepower of the motor can be used with a general formula to get a ballpark figure for Torque requirements. The value of “K” service factor is either 1.5 or 3 depending on the application. 1.5 is used when the application is “light duty” (Low cycle rate, dwell before starting and stopping) 3.0 when the application is “Heavy Duty” (High Cycle rate, continuous starting and stopping). Here are the variable definitions:

P = motor output power, HP
ω = motor speed, rpm
k= service factor

Formulas are to be considered reference only. Please consult SEPAC Engineering prior to final product selection.

TD = 0.1047(Iω)/t

Inertia
Speed
Time
Calculate Static Torque!
Torque Required

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### Calculate Starting/Stopping Torque

To calculate the Torque required to start or stop an inertial load, the result is multiplied by a safety/service factor of 1.25. Consider the following variables:

I – Rotational load inertia, lb-in-sec2
ω – Differential slip speed, rpm
t – Time to speed, sec

Note: 0.1047 is a factor that converts rad/sec to rpm

Formulas are to be considered reference only. Please consult SEPAC Engineering prior to final product selection.

TH = (T/GR) x K

Output Torque
Gear Ratio
Service Factor
Calculate Holding Torque!
Torque Required

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### Calculating Torque vs. Speed

For use cases that have a motor, drive, and a gearbox, it’s important that the brake be located at the high-speed end—most commonly the motor end. Mounting the brake on the motor end allows a smaller brake to be used, but it’s still important to properly calculate the torque required to hold the load. The value of “K” service factor is either 1.5 or 3 depending on the application. 1.5 is used when the application is “light duty” (Low cycle rate, dwell before starting and stopping) 3.0 when the application is “Heavy Duty” (High Cycle rate, continuous starting and stopping).
Determining this torque requires working backwards from the load using the following variables:

TH – Required holding torque
GR – Gear ratio
K – Service factor

Formulas are to be considered reference only. Please consult SEPAC Engineering prior to final product selection.

Inertia

lb-in-S²
kg-cm²
kg-m²
lb-in-S²

Weight/Mass

Kilograms
Pounds
Grams
Ounces

Torque

Nm
lb-in

Dimensions

mm
inch