Technical data

Nominal value

Value of a variable (e.g. voltage, current, resistance ...) for which a motor, fan, pump, its parts or characteristics are measured and by which they are named.

Power input P₁

P₁  Power input in W 
U    Voltage in V 
I     Current in A

Power output P₂

The power output P₂ is always specified for motors.

P₂  Power output in W 
M   Torque in Nm 
n    Speed in min^-1

Efficiency h

The efficiency is the relationship between mechanical power output P₂ and electrical power input P₁.

Example:
At a nominal voltage of 24 V and a nominal current of 35 A, a theoretical wattage rating for the power input P₁:

P1 = UN · IN;   P1 = 24 V · 35 A;   P1 = 840 W.

From this power input P₁ and the power output P_2n determined from the characteristic-curve pattern (see Fig. on page 5), we are able to calculate the efficiency h:

Torque M_N

The torque of a motor is calculated using the following equation:

Nominal speed nN

The nominal speed is the speed output by a motor supplied with nominal voltage and driven with nominal power.

Direction of rotation

Specifications regarding direction of rotation apply when looking onto the shaft end of the motor. In the case of motors with two shaft ends, the shaft end opposite the commutator determines the direction of rotation.

Short-circuit values

The current I_K is the current taken by the motor in the case of short circuit, i.e. in the locked-armature condition. The maximum torque M_K is effective in the case of short circuit.