A 24 V motor is not automatically stronger than a 12 V motor. Select voltage to suit the available supply, then compare torque–speed curves, continuous current, duty cycle and thermal limits. The motor winding, size, magnets, controller and gearbox determine the usable output.
Electrical power and shaft power
For a steady DC input, electrical input power is approximately voltage × current. Shaft power is torque × angular speed. They differ because the motor and drive have losses. Do not turn an electrical wattage figure into a lifting capacity without knowing the mechanism, speed and efficiency.
A lifting calculation with explicit assumptions
For an ideal drum lifting a mass at constant speed, load torque is approximately mass × gravitational acceleration × drum radius. Illustrative example: 10 kg on a 0.02 m drum needs about 1.96 N·m at the drum before friction, acceleration or design allowances. Required lifting speed, gearbox losses, braking and component ratings must also be evaluated. This is not a lifting rating for any Power Motor product.
What changes with a higher bus voltage?
At the same electrical input power, a higher DC voltage implies lower input current. That can affect cable losses and power-stage sizing, but different motor windings may have different speed and torque constants. Applying a higher-than-rated voltage to an existing motor is not a valid way to compare purpose-designed 12 V, 24 V and 36 V versions.
Battery-powered operation
| Check | Why it matters |
| Charged and discharged voltage | The drive must tolerate the complete operating range |
| Startup and peak current | A battery or protection circuit may limit or disconnect the supply |
| Continuous duty | Motor, drive, wiring and battery all have thermal limits |
| Braking energy | The supply or drive needs a supported way to handle returned energy |
| Runtime | Estimate from the actual load cycle, then measure the complete system |
Selection data to provide
- Minimum, nominal and maximum supply voltage.
- Required load speed, continuous torque and short peak duration.
- Run/rest cycle and number of starts or reversals.
- Maximum dimensions, cooling conditions and gearbox arrangement.
- Expected behavior during a jam, supply loss and restart.
Gear motor sizing and torque calculation
Technical reference
maxon: interpreting motor data and speed–torque relationships