Turntable Motor Calculator

Enter Turntable Data

Load Mass

Turntable Mass

Effective Radius

Turntable Speed

rpm

Acceleration Time

Friction Torque

N·m

Gear Ratio

Drive Efficiency

Safety Factor

Service Factor

Extra Process Torque

N·m

Formula Used

The calculator treats the turntable and load as a solid rotating disk. It estimates inertia, angular speed, acceleration torque, output torque, motor shaft torque, and power.

Moment of inertia: I = 0.5 × total mass × radius²
Angular speed: ω = 2π × rpm ÷ 60
Angular acceleration: α = ω ÷ acceleration time
Acceleration torque: T = I × α
Output torque: Ttotal = acceleration torque + friction torque + extra torque
Motor shaft torque: Tmotor = Ttotal ÷ gear ratio ÷ efficiency
Power: P = torque × angular speed
Recommended rating: estimate × safety factor × service factor

Example Data Table

Use Case	Load Mass	Radius	Speed	Acceleration	Friction Torque	Gear Ratio
Display table	60 kg	0.50 m	4 rpm	5 s	4 N·m	15:1
Workshop platform	150 kg	0.80 m	6 rpm	4 s	10 N·m	25:1
Industrial indexer	350 kg	1.20 m	3 rpm	8 s	25 N·m	40:1

How to Use This Calculator

Enter the combined workpiece load placed on the turntable.
Enter the turntable platform mass separately.
Add the effective rotating radius from center to edge.
Set the target table speed in revolutions per minute.
Add acceleration time for startup from rest.
Enter measured or estimated friction torque.
Add gear ratio and drive efficiency.
Choose safety and service factors for practical design margin.
Press calculate and review the result above the form.
Download the result as CSV or PDF when needed.

Turntable Motor Sizing Guide

A turntable looks simple, yet its motor choice needs care. The platform must start, hold speed, and stop without strain. A weak motor may stall during acceleration. An oversized motor may waste money and space. This calculator gives a structured estimate from mass, radius, speed, friction, gearing, efficiency, and safety factor.

Why Torque Matters

Torque is the twisting force that turns the table. It must overcome rotational inertia during startup. It must also cover bearing drag, belt losses, seals, brushes, and product contact. Heavy loads need more torque. Large radii also increase inertia quickly. Doubling radius can create a much larger starting demand.

Speed and Power

Speed is entered as revolutions per minute. The tool converts it into angular speed. Power then comes from torque multiplied by angular speed. This is useful when comparing small geared motors, servo drives, stepper systems, and direct drive units. Power alone is not enough. A motor can have enough watts yet too little starting torque.

Gear Ratio and Efficiency

Gearing changes the relationship between motor speed and table speed. A higher ratio reduces required motor shaft torque after the gearbox multiplication is considered. It also raises motor shaft speed. Efficiency adjusts the estimate for losses in gears, belts, chains, couplings, and bearings. Low efficiency means the motor must work harder.

Safety Margin

Real machines rarely match ideal formulas. Loads may be off center. Surfaces may rub. Bearings may age. Operators may add extra weight. A safety factor helps protect the design. Use a higher factor for industrial tables, frequent starts, uncertain friction, or fragile processes.

Practical Use

Start with measured values where possible. Weigh the table and load. Measure the useful radius from the center. Estimate friction torque by testing the table with a spring scale. Choose the target speed and acceleration time from the process. Then review recommended torque, power, motor speed, and gearbox output.

Interpreting Results

Treat the answer as a planning estimate. Select a motor with equal or higher rated torque. Check peak torque for startup. Confirm gearbox limits, duty cycle, heat rise, and mounting strength. For precision tables, also check backlash, vibration, speed control, and braking needs before final purchase. Document assumptions for later design review.

FAQs

1. What does this turntable motor calculator estimate?

It estimates inertia, angular speed, acceleration torque, running torque, motor shaft torque, motor speed, power, and recommended ratings after safety and service factors.

2. Why is the radius important?

Radius strongly affects rotational inertia. A larger radius places more mass farther from the center, so the motor needs more starting torque.

3. What is friction torque?

Friction torque is the turning resistance from bearings, seals, belts, guides, rollers, and surface contact. Measured values give better results.

4. How should I choose acceleration time?

Use the time required to reach target speed from rest. Shorter acceleration needs more torque. Longer acceleration reduces starting demand.

5. What does gear ratio mean here?

Gear ratio is motor speed divided by turntable speed. A higher ratio increases motor speed and multiplies torque at the table output.

6. Why include drive efficiency?

Efficiency accounts for losses in gears, belts, chains, couplings, and bearings. Lower efficiency increases the required motor torque and power.

7. Is power enough for motor selection?

No. Check torque, speed, duty cycle, gearbox rating, mounting style, braking needs, and thermal limits before selecting the final motor.

8. Should I use a safety factor?

Yes. A safety factor allows for unknown friction, off-center loads, wear, shock, process changes, and imperfect data during early design.